Chapter 1 - Mapúa Institute of Technology

Chapter 1 - Mapúa Institute of Technology
OBSTACLE DETECTION FOR A
SPEECH-CONTROLLED
DC MOTOR OPERATED
WHEELCHAIR
WITH ELEVATION SYSTEM
By
Lloyd Edwinson S. Arellano
Darryll Jade E. Arias
Francis Mark Adriane G. Luna
Aljon C. Santillan
A Thesis Report Submitted to the School of Electrical Engineering,
Electronics Engineering, and Computer Engineering in Partial
Fulfillment of the Requirements for the Degree
Bachelor of Science in Computer Engineering
Mapúa Institute of Technology
March 2012
i
ii
TABLE OF CONTENTS
TITLE PAGE
i
APPROVAL SHEET
ii
TABLE OF CONTENTS
iii
LIST OF TABLES
iv
LIST OF FIGURES
v
ABSTRACT
vi
CHAPTER 1: INTRODUCTION
1
CHAPTER 2: REVIEW OF RELATED LITERATURES AND RELATED STUDIES
4
Speech Recognition
Infrared Proximity Sensor
Direct Current (DC) Motors
Battery Assisted Wheel Chair
Voice Controlled Automation System
A Survey and Experimental Evaluation of Proximity Sensors
for Space Robotics
Switchgear control apparatus and relays for alternating-current circuits
Obstacle Avoidance Fuzzy System for Mobile Robot with IR Sensors
4
5
6
7
7
9
9
10
CHAPTER 3 OBSTACLE DETECTION FOR A SPEECH-CONTROLLED DC MOTOR
OPERATED WHEELCHAIR WITH ELEVATION SYSTEM
12
Abstract
Introduction
Methodology
12
12
13
CHAPTER 4: CONCLUSION
31
CHAPTER 5: RECOMMENDATION
33
BIBLIOGRAPHY
34
APPENDICES
Appendix
Appendix
Appendix
Appendix
35
A. User’s Manual
B. Pictures of Prototype
C. Program Listing
D. Data Sheets
35
38
40
iii
LIST OF TABLES
Table 3.5 Test of effectiveness of the front and back proximity sensors
Table 3.6 Test of effectiveness of the bottom proximity sensors
Table 3.7 Measurement of distance in obstacle detection
Table 3.8 Measurement of the response time in performing the movement
command
Table 3.9.A Determination of the obstacles that can be detected by front and
back sensors
Table 3.9.B Determination of the obstacles that can be detected by bottom
sensors
iv
LIST OF FIGURES
Fig 3.1 Conceptual Framework of the study
Fig 3.2 Methodology Block
Fig 3.3.A Speech Recognition Module Flowchart
Fig 3.3.B Speech Recognition Algorithm
Fig 3.4.A Elevation System Flowchart
Fig 3.4.B Elevation System Algorithm
Fig 3.5.A Obstacle Detection Flowchart
Fig 3.5.B Obstacle Detection Algorithm
v
Abstract
Nowadays, most handicapped people who suffer mobility problem
primarily depend on using wheelchairs and most of these wheelchairs are already
automated. The designs are made in response to the condition of the target
user. Considering the users who already lost the ability to use their hands, the
researchers of this paper believe that implementing a speech control mechanism
and incorporating sensors to the wheelchair will give solution to this problem. It
is also believed that to improve its functionality, a lifting mechanism should be
considered to allow the user to move up by himself into elevated platforms. As a
result, an obstacle detection for a speech controlled dc-operated wheelchair with
elevation system is considered in this paper. The wheelchair will use voice
module that will process the user input speech command and a microcontroller
to control the movement of the wheelchair in response to the user input
command. Proximity sensors will also be used to create a system wherein
obstacle detection mechanism is present. Lastly, for the elevation system the
wheelchair will be incorporated by an electric car jack that will allow itself to lift
into the elevated platform.
Keywords: Voice module, Electric car jack, PIC microcontroller, DC
motors,Proximity Sensors
vi
Chapter 1
INTRODUCTION
Wheelchairs are one of the commonly used devices for assisting human
mobility. It was invented as a solution to the mobility problems of paralytic
people. Most of these people are those who suffer serious cases and totally lost
their mobility. An ordinary wheelchair is a big help to them but still needs
another person for assistance.
Nowadays, there are various types of wheelchairs that already exist. Some
of the innovations made the manually operated wheel chair into an automated
system. The most common type of automated wheelchair is the one controlled
through buttons and joysticks. Other designs implement some advance
technology such as wireless application and voice recognition to improve the
existing wheelchair designs. These wheelchairs are generally prescribed for those
people who experience difficulty in using manual wheelchair due to arm and
other disabling conditions. The condition of the user indicates the type of
electronic wheelchair to be used. For some cases, when the user lacks
coordination with his finger, hand controlled wheelchair would not be advisable.
Other means of controls must be implemented for the convenience of the
patient.
Although there are a lot of studies regarding the improvement of a
wheelchair, most of these are concentrating on the application of easier manual
control or voice recognition alone and do not give more concern on the safety of
1
the users. Most of them do not have the ability to elevate the wheelchair and
thus make it less reliable when the user goes to different places alone.
This study aims to design an obstacle detection mechanism for a speech
controlled wheelchair with elevation to improve safety of users.
The specific
objectives of this study are the following: a) To design an obstacle detection
mechanism using proximity sensors b) To specify possible obstacles that the
wheelchair can detect c) To determine the effectiveness of proximity sensors
when used for obstacle detection.
With the completion of this study, people who are having problems with
mobility will have fewer worries when it comes to their safety in using a
wheelchair. They will also have the benefit of using a speech recognition
wheelchair that would allow them to manipulate the direction where they would
like to go and can elevate themselves to a certain level without using physical
strength.
The obstacle detection mechanism comprises of proximity sensors that
can be activated to avoid accidents like falling down from a gutter and hitting a
wall. Speech recognition technology is applied to the wheelchair. There will be a
headset to be worn by the user to serve as his medium of control for the device.
There are also 2 emergency buttons; one for stop and another one for enabling
and disabling the obstacle detection system. The wheelchair will consist of 7
commands, namely, move forward, move backward, move left, move right, stop,
move up (to elevate), and move down. The headset will receive voice command
2
from the user to determine the movement of the wheelchair and even allow it to
be elevated upon command. For instance, the user says “move-forward”, the
voice command will trigger the forward movement of the device. Similarly, there
will be another voice command for the wheelchair to turn either to the right or
left direction and to elevate or not. The input command from the headset will be
transmitted to the microcontroller through wires. The microcontroller will be
responsible in processing the input from the user. DC motors will be applied on
the wheel chair as well as relay drivers. The DC motors will serve as the main
machine in moving the device. The power will then be supplied by batteries. On
the other hand, the relay drivers will be used to supply enough power to the
motors. The microcontroller itself is not capable of providing the needed power
of the motors. The use of wheelchair is limited due to the source of power which
is a battery. The wheelchair can only perform one movement operation at a time
and has a stable speed. People who are mute cannot use the wheelchair. The
wheelchair has a limit on how high it can elevate and is mostly used only for
sidewalk banks. The design cannot elevate on stairs due to simultaneous
elevation. The obstacle mechanism can only detect large obstacle like walls and
can also detect near falling off platform. When the obstacle detection system
detects an obstacle it will then make the wheelchair to immediately stop
automatically. To enable the elevation, the user must first disable the obstacle
mechanism.
3
CHAPTER 2
REVIEW OF RELATED LITERATURE
For the past decades, evolution of ways to improve technology that will
support people with mobility problems has been given a lot of attention. Because
of the latest trend of technology, people were able to communicate with
machines through programs. Speech is a natural mode of communication for
people and with the use of the latest technology, people have created speech
recognition programs.
Speech Recognition
Speech recognition, often called automatic speech recognition, is the
process by which a computer recognizes what a person says. Speech recognition
is the ability of a machine or program to identify words and phrases in spoken
language
and
convert
them
to
a
machine-readable
format.
However,
rudimentary speech recognition software has a limited vocabulary of words and
phrases and may only identify them if they are spoken very clearly. More
sophisticated software has the ability to accept natural speech. Speech
recognition applications include call routing, speech-to-text, voice dialling, and
voice search. Speech recognition software has two primary components. The first
piece, called the acoustic model, analyzes the sounds of the voice and converts
them to phonemes, the basic elements of speech. The second major component
of speech recognition software is the language model which analyzes the content
of the speech. It compares the combinations of phonemes to the words in its
4
digital dictionary (Miastkowski, 2000). The structure of a standard speech
recognition system is illustrated in the figure below:
Infrared Proximity Sensor
Infrared proximity switches work by sending out beams of invisible
infrared light. A photodetector on the proximity switch detects any reflections of
this light. These reflections allow infrared proximity switches to determine
whether there is an object nearby. Proximity switches with just a light source
and photodiode are susceptible to false readings due to background light. Thus,
more complex switches modulate the transmitted light at a specific frequency
and have receivers which only respond to that frequency. Proximity sensor
captures the reflected infrared signal. The proximity readout is linearly
proportional to the captured infrared-light signal intensity and inversely
proportional to the square of the distance (Luo & Schmitz, 2009).
5
Different types of proximity sensors can be used but Infrared Proximity
sensors would be the best choice because of their sensitivity.
Direct Current (DC) Motors
In any electric motor, operation is based on simple electromagnetism. A
current-carrying conductor generates a magnetic field; when this is placed in an
external magnetic field, it will experience a force proportional to the current in
the conductor, and to the strength of the external magnetic field. The internal
configuration of a DC motor is designed to harness the magnetic interaction
between a current-carrying conductor and an external magnetic field to generate
rotational motion.
At a simplistic level, using DC motors is pretty
straightforward; put power in, and get rotary motion out (Seale, 2003). DC
motors are used on the design as a source of power in elevation and movement
of the wheelchair.
6
Related Studies
Battery Assisted Wheel Chair
This research deals with series hybrid combination of manual and battery
powered wheelchair. The control scheme used is simpler than other hybrid
wheelchairs. It includes the sensor less control of the speed. Battery assisted
wheelchair (BAW) which is operated by a DC motor and has less number of
components in its hardware. Effort made by rider is reduced considerably. The
control scheme also includes the dead man’s switch feature. Speed loop is
provided for the smooth variation of the speed. The current limit is governed by
peak current mode control (Rahulanker & Ramanarayanan, 2006).
Voice Controlled Automation System
This paper discusses speech recognition and its application in control
mechanism. Speech recognition can be used to automate many tasks that
usually require hands-on human interaction, such as recognizing simple spoken
commands to perform something like turning on lights or shutting a door or
driving a motor. Despite these breakthroughs, however, current efforts are still
far away from a 1000/0 recognition of natural human speech. Therefore, the
project is considered but it involves processing of a speech signal in any form as
a challenging and rewarding one. In this paper, a block diagram was used to
show the sequence on how speech will be processed.
7
Pattern matching was also discussed and was stated that the comparison of two
speech signals is nothing but basically their pattern matching. The speech signal
can be represented as the set of numbers representing certain features of the
speech that is to be described. For further processing, it is useful to construct a
vector out of these numbers by assigning each measured value to one
component of the vector. It is also stated that an uttered voice can differ from a
stored template due to interference, noise, and other magnitude distortions
which corrupt the input signal and can make it sound different from the
reference signal. Also, unexpected pauses, unusually fast or slow speaking
styles, and other changes in speed can randomly shift the position of the input
relative to the template. The same person can utter the same word in slightly
different ways each time. The person can pause, speak faster, speak slower, or
emphasize
certain
syllables.
These
differences
are
called
intra-speaker
differences. The differences between the same words uttered by the different
speakers or different words uttered by same speaker or different speakers are
called inter-speaker differences. These differences are large as compared to intra
speaker differences (Haleem, 2008).
8
A Survey and Experimental Evaluation of Proximity Sensors for Space
Robotics
The paper provides an overview selection process for proximity sensors
for manipulator collision avoidance. Five categories of sensors have been
considered for this use in space operations: intensity of reflection, triangulation,
time of flight, capacitive, and inductive. From these categories, the most
promising commercial and mature laboratory prototype sensors have been
selected and tested. After reviewing the selection process and the experimental
results, conclusions are drawn about which sensors are best and why. The report
has detailed the selection of proximity sensors for manipulator collision
avoidance. In this paper proximity sensors were tested and their capabilities
were known. Optical intensity of reflection sensors are probably the most widely
available in the number of manufacturers, the number of models, and the ranges
of operation. Many of these sensors have adjustable ranges, which are set by
turning a potentiometer on the sensor housing. Therefore, the ranges listed for
some sensors may not be attainable by one sensor setting (Volpe & Ivlev, 1994).
Switchgear control apparatus and relays for alternating-current circuits
The paper stated that control relays are a standard practice for a correct
design and it is very important to lay-out such relays in the circuit. With this, the
system depends on the proper action of relays because this will take a large part
on the success of the operation of circuit. Implementing relays to control a circuit
9
requires that the circuit must be controlled by only one signal. Multiple relays can
be activated at the same time, thus a different operation must be done with
single activated relay; different combinations can have different operations. In
the article, relays are used to control the alternating currents of a switchgear
control apparatus. The relay here has a single moving element which moves
under the action of the currents. The team also stated that if the circuit is in
breakdown, the overload on the single overloaded phase must be much greater
than before for the relay to operate. This means that if the circuit has no relays
the overloading will occur simultaneously on each of the operation phases but if
relays are installed, this overloading will only occur in only one phase, thus make
the circuit safe for more damage that it will take from breakdown (Garrard,
2010).
Obstacle Avoidance Fuzzy System for Mobile Robot with IR Sensors
The paper deals with the navigation problem of mobile robots in an
unknown indoor environment with the use of infrared sensors. In this paper, the
robot has the ability to plan motion and to navigate autonomously avoiding any
type of obstacles. This is a reactive strategy and is completely based on sensory
information. This gives the idea that infrared sensors can be used as proximity
sensors for an obstacle detection mechanism. It has been stated in the article
that infrared detectors have built-in optical filters that allow very little light which
is the main idea of detecting an obstacle whether it is physically present or not.
10
By using infrared sensors, a program can be designed for obstacle detection and
thus allow the possibility of creating a machine that would be used for collision
avoidance. This article proves that a collision free navigation system is possible in
a machine that uses infrared sensors and is programmed in the most appropriate
way they should be.
11
Chapter 3
OBSTACLE DETECTION FOR A SPEECH-CONTROLLED
DC MOTOR OPERATED WHEELCHAIR WITH ELEVATION SYSTEM
Abstract
A speech-controlled dc motor operated wheel chair with proximity sensors
as an obstacle detection is proposed in this paper. The user can control the
wheel chair through speech command and is capable of moving forward, turning
either to the left or right direction and can climb up elevated surfaces.
Introduction
Most automated wheelchairs nowadays implement advance technology in
their designs. Some designs implement different medium of control like buttons,
joysticks and wireless technology to make wheelchair more convenient to use.
But in some cases, these existing designs are not enough to give solution for the
mobility of people who suffer extreme case of disability. Some of these people
have already lost the functionality of their arm. In such cases, where buttons,
joysticks and other arm-controlled medium are not anymore applicable, a speech
controlled wheelchair can be used. Additional safety features will also be needed
to ensure the safety of the user. The combination of a speech controlled
wheelchair and proximity sensor would allow the user to move independently
without worrying about his safety.
12
Methodology
The study is divided into 3 major parts. The first part is all about the
implementation of speech control to a dc operated wheelchair. The next part is
designing the elevation system for the wheel chair. And the last part, which is
the core of the study, is all about the development of obstacle detection
mechanism.
Figure 3.1 below shows the conceptual framework of the study. The figure
shows the process in designing the speech controlled dc operated wheelchair
with an obstacle detection mechanism.
Elevation motors
Wheelchair
DC motors
Microcontroller
Speech
Recognition
Module
Sensors
Fig 3.1 Conceptual Framework of the study
The design process starts by incorporating DC motors to the
manually operated wheel chair. This DC motors will be responsible for the
movement of the wheelchair. There will be 4 DC motors to be applied. Each
13
wheel at the back will have its own motor to operate and another 2 motors for
the elevation process. These motors will be controlled by the microcontroller. In
this study, the researchers will use a PIC16F877A microcontroller.
This
microcontroller will control the movement of the motors depending on the input
it receives. The input will come from the speech recognition module. Each
wheelchair movement has a corresponding speech command. The last process is
the integration of proximity sensors on the wheelchair. The proximity sensors will
serve as the medium in detecting obstacle in the wheelchair’s movement.
Figure 3.2 shows the methodology block of the study.
Review of Related Literature
Integration of Hardware and Software
components
Development of hardware components
Testing
Development of Speech Recognition
Algorithm
Results and Discussion
Development of the Wheelchair Elevation
System
Conclusion
Development of Obstacle Detection
System
Fig 3.2 Methodology Block
14
The first step the researchers must do is to do a review of related
literatures about the study. Through this, the researchers will be able to
determine the needed materials as well as the necessary steps in designing the
device. After the review of related literatures, the researcher will develop the
hardware components. This includes the integration of the basic hardware parts
such as the DC motors, electric car jack, relays, microcontroller, battery and
speech recognition module. Then the next step is to develop the speech
recognition module algorithm.
Figure 3.3 shows the speech recognition module flowchart and
algorithm. It describes the flow of program to be designed for the speech
recognition module.
15
Start
Input First Speech
Command
No
Yes
Valid Speech
Command
If Speech Command
== Stop
Perform Stop
Function
If Speech Command
== Move
Input Second
Speech Command
Yes
Valid Speech
Command
No
1
No
If Speech Command
== Forward
Perform Forward
Function
Obstacle
Detected
Yes
Obstacle
Detected
If Speech Command
== Backward
Obstacle
Detection
System
No
Perform Backward
Function
Yes
Obstacle
Detected
If Speech Command
== Right
No
Perform Right
Function
Yes
If Speech Command
== Left
Obstacle
Detected
No
Yes
2
16
Perform Left Function
3
3
2
Input Stop
Command
Elevation
System
Perform Stop
Function
1
End
Fig 3.3.A Speech Recognition Module Flowchart
Start
get First Speech Command
If Speech Command is Valid
Switch (First Speech Command)
Case “Stop”:
Perform Stop Function; Break;
Case: “Move”
Input Second Speech Command
If Speech Command is Valid
Switch (Second Speech Command)
Case “Forward”:
Call Obstacle Detection System;
If Obstacle is considerable
else
Perform Forward Function;
Break;
Case “Backward”:
Call Obstacle Detection System;
17
End
If Obstacle is considerable
else
Perform Backward Function;
Break;
Case “Left”:
Call Obstacle Detection System;
If Obstacle is considerable
else
Perform Left Function;
Break;
Case “Right”:
Call Obstacle Detection System;
If Obstacle is considerable
else
Perform Forward Function;
Break;
Default:
Call Elevation System Function;
Get Stop Input Command
Perform Stop Command
Fig 3.3.B Speech Recognition Algorithm
First, the speech recognition will accept a first degree command of move
or stop. When the command is Stop, it will perform the stop function that
instantly stops the current function of the wheelchair. While when the command
is Move, it will wait for a second degree command such as forward, backward,
left, right, up and down.
Forward, Backward, Left and Right commands will
trigger the obstacle detection system while Up and Down commands will affect
the elevation system. Other commands that are not included in the given sets of
command are voided.
After designing the algorithm for the speech recognition module,
the implementation of the elevation system is next. This includes integrating the
18
other 2 DC motors to the wheelchair. One motor will be responsible for lifting the
wheelchair while the other one is for the forward movement of the wheelchair
while being elevated.
Figure 3.4 below shows the algorithm for the elevation mechanism
of the wheelchair. First, there will be an input speech command from the user.
The input speech command will be verified if it is for elevating the wheelchair or
for moving it down”. If the command falls either for these commands, that
specific command will be executed. If it is invalid, the microcontroller will do
nothing.
Start
F
Perform
up?
F
Perform
Down?
T
T
Perform Down
Function
Perform Up
Function
End
Fig 3.4.A Elevation System Flowchart
19
Start
Return
If Operation is Up
Perform Up Function
Else
Perform Down Function
Fig 3.4.B Elevation System Algorithm
When the speech recognition module and elevation system
algorithm are finished, the next thing to design is the mechanism for obstacle
detection of the wheelchair. In this part, the speech controlled wheel chair will
be integrated with proximity sensors. There will be proximity sensors to be
attached at the front and back of the wheelchair. There will also be another set
of proximity sensors at the bottom of the wheelchair. This is for detecting
dangerous places such as stairs, cliffs and etc. The flowchart and algorithm for
the obstacle detection are described respectively below
1
Start
F
T
F
Sensor1
Clear Signal1
Set Signal1
F
Clear Signal4
Clear Signal5
T
T
Sensor6
Clear Signal6
Set Signal3
1
Set Signal5
F
Sensor3
Clear Signal3
T
Sensor5
Set Signal2
F
Set Signal4
F
T
Sensor2
Clear Signal2
T
Sensor4
Set Signal6
Fig 3.5.A Obstacle Detection Flowchart
End
20
Start
If Sensor1 Detects an Obstacle
Set Signal1
Else
Clear Signal1
If Sensor2 Detects an Obstacle
Set Signal2
Else
Clear Signal2
If Sensor3 Detects an Obstacle
Set Signal3
Else
Clear Signal3
If Sensor4 Detects an Obstacle
Set Signal4
Else
Clear Signal4
If Sensor5 Detects an Obstacle
Set Signal5
Else
Clear Signal5
If Sensor6 Detects an Obstacle
Set Signal6
Else
Clear Signa6
Return
Fig 3.5.B Obstacle Detection Algorithm
21
First, there will be a speech command input from the user.
Then after receiving an input voice command from the user, there will be
continuous checking of obstacles in that specific direction in relation to the
inputted voice commands. If there is an obstacle, there will be no operation, but
if there is no obstacle detected, then the command will be executed.
The next step is to integrate the hardware with the software
components. The algorithm for the speech recognition module, the elevation
mechanism algorithm and the obstacle detection algorithm, will be programmed
to the microcontroller in interfacing the hardware to the software.
Testing and Interpretation of Results
In order to further support the study, testing will be performed
after the process of integrating the software and hardware is done. There will be
four types of test that will be performed in measuring the performance of the
design.
Test on the effectiveness of the front and back proximity sensors
The first test focuses in measuring the effectiveness of the front
and back sensors in obstacle detection. The purpose of this test is to determine if
the proximity sensor is effective in detecting the obstacle to avoid collision. In
22
this test, four of the wheelchair’s movement command will be tested upon the
obstacles located at varying locations as described in Table 3.5. Upon
encountering an obstacle, the wheelchair will disable the movement command
used with respect to the location of the obstacle.
The procedures to be performed for this test are described below.
Procedure:
1.) The four movement commands namely “move forward”, “move
backward”, “move left” and “move right” will be put to test while
obstacles are placed on different location as specified in Table 3.5
2.) The movement command that will not be done in response to the
detection of an obstacle will be marked as “disabled” and others will be
marked as “working”.
3.) Results will be obtained and recorded at the given table.
Table 3.5 Test of effectiveness of the front and back proximity sensors
Location of
obstacle
1.) Front
2.) Back
3.) Left
4.) Right
5.) Front and
Left
6.) Front and
Right
7.) Front and
Back
8.) Back and
Right
Forward
Command
Disabled
Working
Working
Working
Disabled
Backward
Command
Working
Disabled
Working
Working
Working
Turn Left
Command
Working
Working
Disabled
Working
Disabled
Turn Right
Command
Working
Working
Working
Disabled
Working
Disabled
Working
Working
Disabled
Disabled
Disabled
Working
Working
Working
Disabled
Working
Disabled
23
9.) Back and Left
10.) Left and
Right
11.) All direction
Working
Working
Disabled
Working
Disabled
Disabled
Working
Disabled
Disabled
Disabled
Disabled
Disabled
As shown, Table 3.5 shows that the design is successful in disabling
the movement of the wheelchair upon encountering an obstacle. All of the
wheelchair’s movement commands tested show independent behavior in
response to the obstacle detected. As shown in the table, the obstacle detected
at the front will not affect the functionality of the other movements like move
back, move left and move right.
Test on the effectiveness of the bottom proximity sensors
After performing the first test, the next test will be performed. This
test focuses in measuring the effectiveness of the bottom sensors. The purpose
of this test is to determine if the proximity sensors is effective in detecting
continuous surface which will help in avoiding accidents like falling from stairs
and etc. Similar to the first test, the four movement command will be tested
upon discontinuous surface (stairs, gutter etc.) at varying locations. Upon
encountering no floor surface, the wheelchair will disable the movement
command used with respect to the location of the discontinuous surface.
24
The set of procedures to be performed for this test is described
below.
Procedure:
1.) The four movement command namely “move forward”, “move
backward”, “move left” and “move right” will be put to test with the
position of the discontinuous path on different positions.
2.) The movement command that will not be done in response to the
detection of an obstacle will be marked as “disabled” and others will be
marked as “working”.
3.) Results will be obtained and recorded at the given table.
Table 3.6 Test of effectiveness of the bottom proximity sensors
Location of
discontinuous
path
1.) Front
2.) Right
3.) Left
4.) Front and
Right
5.) Front and Left
6.) Right and Left
Forward
Command
Backward
Command
Turn Left
Command
Turn Right
Command
Disabled
Working
Working
Working
Working
Working
Working
Working
Working
Working
Disabled
Working
Working
Disabled
Working
Disabled
Disabled
Working
Working
Working
Disabled
Disabled
Working
Disabled
Table 3.6 shows that the wheelchair is completely successful at
disabling the movement command upon encountering a discontinuous path.
Results shown in Table 3.6 show the same response in relation to the results
shown in Table 3.5. The disablement of each command is independent to other
25
commands. On the other hand, some of the limitations that had been observed
during the implementation of test is that the discontinuous path cannot be
detected when it is located at the back.
Measurement of distance in obstacle detection
The next test to be performed is to measure the distance at which
the wheelchair can detect obstacles. The purpose of this test is to determine at
how far the wheelchair will disable its movement upon encountering an obstacle.
The data obtain would help in determining if the wheelchair is disabling the
commands accurately in the distance specified by the designers.
The procedures to be performed for this test are described below.
Procedure:
1.) The four movement command namely “move forward”, “move
backward”, “move left” and “move right” will be put to test with an
obstacle placed at varying distance from the wheelchair.
2.) Upon stopping of the wheelchair in doing the movement command,
the distance of the wheelchair will be measured from the obstacle.
3.) Results will be obtained and recorded at the given table.
26
Table 3.7 Measurement of distance in obstacle detection
Distance
of
obstacle
1.)
2.)
3.)
4.)
5.)
6.)
7.)
0.2
0.4
0.6
0.8
1.0
1.2
1.4
m
m
m
m
m
m
m
Distance at
which
Forward
Command is
disabled
Distance at
which
Backward
Command is
disabled
Distance at
which Turn
Left Command
is disabled
Distance at
which Turn
Right
Command is
disabled
0.2m
0.4 m
0.6 m
0.8 m
0.8 m
0.8 m
0.8 m
0.2m
0.4 m
0.6 m
0.8 m
0.8 m
0.8 m
0.8 m
0.2m
0.4 m
0.6 m
0.8 m
0.8 m
0.8 m
0.8 m
0.2m
0.4 m
0.6 m
0.8 m
0.8 m
0.8 m
0.8 m
Table 3.7 shows the results in testing the obstacle detection of the
wheelchair at varying distances. Results show that at a range of less than or
equal to 0.8 meters (distance ≤ 0.8m), the wheelchair would disable the
movement command. When the distance of the obstacle is greater than 0.8m,
the wheelchair will continue its forward or backward movement until it reaches
0.8 meters from the obstacle. The same goes in performing the move left and
right command. The wheelchair will continue to rotate when the distance of the
obstacle is not on the range of detection of the wheelchair.
Measurement of the response time in performing the movement command
The next test focuses in determining the response time of the
wheelchair. The purpose of this is to identify the time interval at which the
wheelchair will perform the movement command specified by the user.
27
The set of procedures to be performed for this test is described
below.
Procedure:
1.) All of the wheelchair’s speech commands will be tested by the
researcher.
2.) The researcher will measure the time interval upon the glowing of the
orange LED button up to the time the wheelchair started to perform
the command.
3.) Results will be obtained and recorded at the given table.
Table 3.8 Measurement of the response time in performing the
movement command
Speech Command
Response Time
1.) Move Forward
0.593 sec
2.) Move Left
0.597 sec
3.) Move Right
0.6 sec
4.) Move Up
0.593 sec
5.) Move Down
0.595 sec
6.) Move Backward
0.6 sec
7.) Stop
0.595 sec
28
Table 3.8. shows the results of the test in measuring the response
time in performing the speech command. Based form the results, the time
interval in performing the speech commands is approximately 0.6 sec.
Determination of the obstacles that can be detected
The last part of the test focuses in determining the possible
obstacle that the wheelchair can detect. This test covers all the proximity sensors
including those installed at the bottom of the wheelchair. The purpose of this
test is to determine the limitations as well as the capabilities of the wheelchair in
obstacle detection. In this test, those obstacles specified at Table 3.8 that can be
detected will be marked as “success” while those cannot be detected will be
mark as “failed”
The set of procedures to be performed for this test is described
below.
Procedure:
1.) The wheelchair’s obstacle detection will be tested for 5 consecutive
trials for each obstacles specified in Table 3.7.
2.) Results will be obtained and recorded at the given table.
3.) Upon obtaining the results in each trial of the given types of elevated
platforms, the percentage of success will be computed. Computing for
the percentage of success is described by the formula below:
29
The percentage of success for each type of obstacle will determine
if the wheelchair is either capable or not capable of detecting that specific
obstacle. Obstacles with a percentage of success lower than 80% will be
considered to be an object
Table 3.9.A Determination of the obstacles that can be detected by
front and back sensors
Obstacles
Front and Back Proximity Sensors
Trial
1
Trial
2
Trial
3
Trial
4
Trial
5
Percentage of
Success
(%)
Solid Objects
1.) Gate
Success
Success
Success
Success
Success
100%
2.) Wall
Success
Success
Success
Success
Success
100%
3.) Human
Success
Success
Success
Success
Success
100%
Failed
Success
Failed
Failed
Success
40%
5.) School Table
Success
Success
Success
Success
Success
100%
6.) School Chair
Success
Success
Success
Failed
Success
80%
4.) Lamp Post
Translucent/Glass/Light passing Objects
1.) Mirror
Success
Failed
Failed
Success
Success
60%
2.) Sliding Glass
Door
3.) Curtains
Success
Success
Failed
Success
Success
80%
Success
Success
Success
Success
Success
100%
4.) Stainless Roof
Success
Success
Success
Success
Success
100%
Colored Obstacles (Wall)
1.) Red colored
obstacle
2.) Yellow colored
obstacle
3.) White colored
obstacle
4.) Brown colored
obstacle
5.) Blue colored
obstacle
Success
Success
Success
Success
Success
100%
Success
Success
Success
Success
Success
100%
Success
Success
Success
Success
Success
100%
Success
Success
Success
Success
Success
100%
Success
Success
Success
Success
Success
100%
30
Table 3.9.B Determination of the obstacles that can be detected by
bottom sensors
Obstacles
Bottom Proximity Sensors
Trial
Trial
Trial
3
4
5
Trial
1
Trial
2
1.) Stairs
Success
Success
Success
Success
Success
Percentage of
Success
(%)
100%
2.) Gutter
Success
Success
Success
Success
Success
100%
3.) Man Hole
Success
Success
Success
Success
Success
100%
4.) Pothole
Success
Success
Failed
Success
Failed
80%
Failed
Failed
Failed
Failed
Failed
0%
5.) Inclined Plane
Table 3.8.A shows the results of the test in detecting various types
of obstacles. Based from the results, the wheelchair is able to easily detect an
object with wide and large area. On the other hand, a thin object like the lamp
post shows lower percentage of success compared to other obstacles. Also based
from the results, reflective objects are not easily detected by the proximity
sensors. And in terms of the color of the obstacles, the obstacle detection of the
system is not much affected by color of the obstacle. The obstacle detection of
that specific object (even with varying color) shows high percentage of success
in terms of detection.
Table 3.8.B shows the result in detecting discontinuous paths.
Based from the results, the wheelchair is able to detect steep surfaces as
described in the table. Movement commands are still working at shallow
discontinuous surfaces such as an inclined plane is not considered as an
obstacle.
31
Chapter 4
CONCLUSION
In this paper, a hardware design of obstacle detection of a speech control
with elevation system is presented. This design is intended mainly for the use of
handicapped persons especially those who have lost their ability in using their
arms and to insure that the user will be safe while using the hardware design.
The design is guided by a main objective and specific objectives. The main
objective is met. The device is able to detect the given
specific obstacles
mentioned in the objectives and tests. The obstacle detection system of the
device consists of six infrared sensors. The sensors will be controlled by the PIC
16F877A. The two pair of sensors will be responsible for detecting hindrance
objects while the other pair of sensors will be detecting if the wheelchair will
encounter situation wherein it will fall.
In terms of obstacle detection, the design has successfully met this
objective. The hardware design is able to detect obstacles using infrared
proximity. The pair of sensors at the front and back of the wheelchair detects at
a range of distance ≤ 0.8m form the obstacle thus, preventing the wheelchair
from possible collisions. Upon detection of the obstacle, the wheelchair will halt
its movement operation. That specific movement command will be disabled until
such time that there is no obstacle detected. The same goes to the bottom
sensors. The movement of the wheelchair will continue until such time that the
32
sensors do not detect the floor. Upon encountering discontinuous path, that
specific movement commands with will be disabled.
Another objective of the study is to determine the possible objects that
the wheelchair can detect. Based on the results, the wheelchair is able to detect
wide and large obstacles. Thin objects are sometimes not detected due to the
position of the sensors which are located at the arm of the wheelchair. Reflective
objects also show lower detection especially in bright environments. In terms of
the obstacle colour, the capability of infrared proximity sensors in obstacle
detection are not much affected. In terms of the bottom sensors detection, the
wheelchair is able to detect steep surfaces.
To summarize it all, the obstacle detection of the wheelchair helps
improve the safety of the user. The wheelchair is able to automatically stop upon
encountering an obstacle which will help in preventing collisions. It is also able to
detect discontinuous surfaces which will help the user to prevent accidents like
falling into the stairs and etc. There is also an emergency stop button installed to
stop the wheelchair movement in case of emergency.
Some of the limitations of the wheelchair design are:
1.) Wheelchair cannot detect discontinuous surface at the back of the
wheelchair
2.) Obstacle detection does not work accurately at extremely bright
environment.
33
Chapter 5
RECOMMENDATION
Some modifications can be made to improve the design prototype in order to
please the user and receive a positive feedback. The recommendations are as
follows:
1. Addition of possible obstacles it can detect by installing additional sensors at
the blind spot of the wheelchair specifically at the middle front and middle back.
2. Provide an LCD display that would inform the user how high the system has
elevated and at the same time show the battery level.
3. Improve the speech recognition system by using noise filters.
4. Installation of backrest and seat cushion for the users comfort.
5. Improve the maximum weight limit by installing supports at the bottom of the
wheelchair.
6. Improve the maximum height limit the wheelchair can elevate.
7. Change the location of the bottom proximity sensors that will enable the
wheelchair to stop at long distance from the discontinuous surface.
8. Add a feature that will enable the wheelchair to be moved manually in
instance that the wheelchair can no longer move.
34
Bibliography
R. Rahulanker, V. Ramanarayanan (2006). Battery Assisted Wheel Chair, 2006
IEEE Region, 167 – 171.
Haleem, M.S. (2008). Voice Controlled Automation System, 2008 IEEE Region,
508 - 512.
Volpe, R., Ivlev, R. (1994). A Survey and Experimental Evaluation of Proximity
Sensors for Space Robotics, 2002 IEEE Region, 3466 - 3473.
C. Garrard (2010). Switchgear control apparatus and relays for alternatingcurrent circuits, 2010 IEEE Region, 588-611.
Rusu, C.G., Birou, I.T., Szö ke , E. (2009). Fuzzy based obstacle avoidance
system for autonomous mobile robot, 10th International Conference on
Development and Application Systems, 26-29.
Cook, N.P (2004). Electronics a complete course, 2nd Edition, McGraw-Hill, USA
Godse, A.P (2007). Microprocessor and microcontrollers, Technical Publications,
USA
35
Appendix A. User’s Manual
This part of the paper describes the important things on how to effectively
use the speech controlled dc-motor operated wheelchair with elevation system.
Also included in this part of the paper are the safety precautions to be followed
by the user.
The following procedures below are the basic steps in operating the
wheelchair:
1. Attached the power supply clips to their respective polarity in the battery.
2. Turn on the power button of the microphone and wait for it to be ready.
(The green LED indicator will blink when the microphone is ready to
accept input.)
3. Input a voice command (either “move” or”stop”).
4. Wait for the green LED indicator to glow. If the green LED glows, proceed
to step 5 else go back to step 3. The green LED will glow if the command
input is valid.
5. If the first word input is “move” then proceed to step 6 else repeat step 3.
6. Input the second voice command (“forward”, ”backward”, ”left”, “right”,
“up”, “down”). An orange LED will glow once the second input word is
recognize else go back to step 3.
7. Wait for the wheelchair’s output and proceed to step 3.
In order to further understand how the wheelchair operates, a summary of
the wheelchair’s function is described by the table below
36
Table 4. Summary of the movement operation of the speech
controlled dc-motor operated wheelchair with elevation system.
First Word Command + Second Word
Wheelchair’s Response
Command
Move + Forward
The wheelchair will continuously move forward
Move + Backward
The wheelchair will continuously move backward
Move + Left
The wheelchair will continuously turn counterclockwise
(rotate left)
Move + Right
The wheelchair will continuously turn clockwise
(rotate right)
Move + Up
The wheelchair will lift its front wheels.
Move + Down
The wheelchair will land its front wheels
Stop
The wheelchair stops from moving
Safety switch- use to as an emergency stop for the wheelchair’s
movement. It is located at the front of the right arm of the wheelchair.
And for the safety precautions in using the design, the information below
will give the user the necessary precautions to be followed to prevent damaging
the wheelchair as well as to prevent accidents.
37
Safety precautions:
1. Always remove the power supply clip from the battery if the wheelchair is
not in used.
2. Always ensure that the power supply clips are correctly attached to the
polarity of the battery. (RED-Positive; BLACK-Negative)
3. As much as possible, turn off the microphone if the wheelchair is not in
used.
4. Remember to always have a hand to the safety switch.
38
Appendix B. Pictures of Prototype
39
40
Appendix C. Program Listing
;*****************************************************************
***
;
filename:
VoiceChair04.asm
processor
16F877A
include
<P16F877A.inc>
__config _HS_OSC & _WDT_OFF & _PWRTE_ON & _LVP_OFF & _BODEN_OFF
& _CP_ALL
;*****************************************************************
***********
;
Variable Declaration
Voice_Var
equ H'20'
;
;
SWA_New
equ H'30'
;
SWA_Prev
equ H'31'
;
SWE_New
equ H'32'
;
SWE_Prev
equ H'33'
;
;
LED1_Tmr
equ H'40'
;
LED2_Tmr
equ H'41'
;
;
Sensor
equ H'42'
;
;
ADC0
equ H'50'
;
ADC1
equ H'51'
;
ADC2
equ H'52'
;
ADC3
equ H'53'
;
ADC4
equ H'54'
;
ADC5
equ H'55'
;
ADC6
equ H'56'
;
ADC7
equ H'57'
;
ADC_Sel
equ H'5A'
;
;
is_data
equ H'60'
;
rx_data
equ H'61'
;
tx_data
equ H'62'
;
;
I
equ H'70'
;
J
equ H'71'
;
;
Temp1
equ H'78'
;
41
Temp2
equ H'79'
;
Temp3
equ H'7A'
;
Temp4
equ H'7B'
;
W_TEMP
equ H'7C'
;
STAT_TEMP
equ H'7D'
;
;*****************************************************************
***********
;
Reset Vector Starts at Address 0x0000.
;*****************************************************************
***********
org 0x0000
; start of reset vector.
goto Initialize
;
;
org 0x0004
; start of interrupt service routine.
goto ISR_routine
;
;*****************************************************************
***********
;
Initialization Routine.
;*****************************************************************
***********
Initialize: clrf TMR0
; Clear TMR0
clrf INTCON
; Disable Interrupts and clear T0IF
bcf STATUS,RP1
;
bsf STATUS,RP0
; Select Bank 1
movlw B'11000011'
;
movwf OPTION_REG
; prescaler of 1:16
;
movlw B'00000001'
;Set PortA and PortE all Analog RA3= +Vref
movwf ADCON1
; Left Justified
;
movlw B'11111111'
;
0=OUT 1=IN
movwf TRISA
; Port A. 11xx xxxx:TTL
;
movlw B'00000000'
;
0=OUT 1=IN
movwf TRISB
; Port B. xxxx xxxx:TTL
;
movlw B'11001111'
;
0=OUT 1=IN
movwf TRISC
; Port C. xxxx xxxx:schmitt
;
movlw B'00000000'
;
0=OUT 1=IN
movwf TRISD
; Port D. xxxx xxxx:schmitt
;
movlw B'00000111'
;
0=OUT 1=IN
movwf TRISE
; Port E. xxxx xxxx:schmitt
42
;
STATUS,RP0
; Select Bank 0
;
call Init_Var
;
call Init_UART
;
call Init_VR
;
;*****************************************************************
***********
;
Main Program Starts Here.
;*****************************************************************
***********
Main:
call VR_Recognize
;
goto Main
;
;*****************************************************************
***********
;
The Interrupt Service Routine.
;*****************************************************************
***********
ISR_routine: nop
; Save Registers
;
retfie
; Return from Interrupt.
;*****************************************************************
***********
Init_Var:
clrf PORTB
;
clrf PORTC
;
clrf PORTD
;
clrf tx_data
;
clrf LED1_Tmr
;
clrf LED2_Tmr
;
movf PORTA,W
;
movwf SWA_New
;
movwf SWA_Prev
;
movf PORTE,W
;
movwf SWE_New
;
movwf SWE_Prev
;
movlw B'10000001'
;
movwf ADCON0
;
clrf ADC_Sel
;
clrf ADC0
;
clrf ADC1
;
clrf ADC2
;
clrf ADC3
;
clrf ADC4
;
clrf ADC5
;
bcf
43
clrf ADC6
;
clrf ADC7
;
clrf Sensor
;
return
;
;*****************************************************************
***********
; Voice Recognition
;================================================
====================
; Constant Declaration
;================================================
====================
; Protocol Command
;
CMD_BREAK
equ "b"
; abort recog or ping
CMD_SLEEP
equ "s"
; go to power down
CMD_KNOB
equ "k"
; set si knob <1>
CMD_LEVEL
equ "v"
; set sd level <1>
CMD_LANGUAGE equ "l"
; set si language <1>
CMD_TIMEOUT equ "o"
; set timeout <1>
CMD_RECOG_SI equ "i"
; do si recog from ws <1>
CMD_RECOG_SD equ "d"
; do sd recog at group <1> (0 = trigger
mixed si/sd)
;================================================
====================
; Protocol Status
;
STS_AWAKEN equ "w"
; back from power down mode
STS_ERROR
equ "e"
; signal error code <1-2>
STS_INVALID equ "v"
; invalid command or argument
STS_TIMEOUT equ "t"
; timeout expired
STS_INTERR equ "i"
; back from aborted recognition (see 'break')
STS_SUCCESS equ "o"
; no errors status
STS_RESULT equ "r"
; recognised sd command <1> - training
similar to sd <1>
STS_SIMILAR equ "s"
; recognised si <1> (in mixed si/sd) training similar to si <1>
;================================================
====================
; Protocol arguments are in the range 0x40 (-1) TO 0x60 (+31) inclusive
ARG_MIN
equ H'40'
; 0x40 = 64 (ascii '@')
ARG_MAX
equ H'60'
; 0x60 = 96 (ascii ''')
ARG_ZERO
equ H'41'
; 0x41 = 65 (ascii 'A')
ARG_ACK
equ H'20'
; 0x20 = 32 (ascii ' ') 'TO READ more status
arguments
44
;================================================
====================
; Wordset
;
WST
equ D'0'
; wordset trigger
WS1
equ D'1'
; Wordset 1 commands
WS2
equ D'2'
; Wordset 2 actions
WS3
equ D'3'
; Wordset 3 numbers
;================================================
====================
;Wordset Commands
;
WS1_Action equ D'0'
;
WS1_Move
equ D'1'
;
WS1_Turn
equ D'2'
;
WS1_Run
equ D'3'
;
WS1_Look
equ D'4'
;
WS1_Attack equ D'5'
;
WS1_Stop
equ D'6'
;
WS1_Hello
equ D'7'
;
;
WS2_Left
equ D'0'
;
WS2_Right
equ D'1'
;
WS2_Up
equ D'2'
;
WS2_Down
equ D'3'
;
WS2_Forward equ D'4'
;
WS2_Backward equ D'5'
;
;
WS3_Zero
equ D'0'
;
WS3_One
equ D'1'
;
WS3_Two
equ D'2'
;
WS3_Three
equ D'3'
;
WS3_Four
equ D'4'
;
WS3_Five
equ D'5'
;
WS3_Six
equ D'6'
;
WS3_Seven
equ D'7'
;
WS3_Eight
equ D'8'
;
WS3_Nine
equ D'9'
;
WS3_Ten
equ D'10'
;
;
WS_Timeout equ D'254'
;
WS_Error
equ D'255'
;
;================================================
====================
; Voice Recognition Variable
45
;================================================
====================
VCountLo
equ Voice_Var +D'0' ;
VCountHi
equ Voice_Var +D'1' ;
VRA
equ Voice_Var +D'2' ;
VRA1
equ Voice_Var +D'3' ;
VRLED
equ Voice_Var +D'4' ;
WS
equ Voice_Var +D'5' ;
RXC
equ Voice_Var +D'6' ;
RXC_PREV
equ Voice_Var +D'7' ;
VR_RecgWait equ Voice_Var +D'8' ;
;================================================
====================
Init_VR:
clrf VCountLo
;
clrf VCountHi
;
clrf RXC
;
clrf RXC_PREV
;
;
call VR_Wakeup
; Wake Up Voice Module
call VR_SetLanguage ;
call VR_SetTimeout
;
;
movlw D'1'
;
movwf WS
;
;
return
;
;================================================
====================
VR_Wakeup: movlw CMD_BREAK
;
movwf tx_data
;
call Send_tx
;
clrf VCountHi
;
clrf VCountLo
;
call Get_rx
;
movlw STS_SUCCESS
; IF VRA <> STS_SUCCESS THEN GOTO
VR_Wakeup
subwf VRA,W
;
btfss STATUS,Z
;
goto VR_Wakeup
;
call Delay
;
return
;
;================================================
====================
VR_SetLanguage:
;
46
movlw CMD_LANGUAGE
;
movwf tx_data
;
call Send_tx
;
movlw D'0'
; english language
addlw ARG_ZERO
;
movwf tx_data
;
call Send_tx
;
movlw D'100'
;
movwf VCountHi
;
VR_LangLoop: clrf VCountLo
;
call Get_rx
;
movlw STS_SUCCESS
; IF VRA = STS_SUCCESS
subwf VRA,W
;
btfss STATUS,Z
;
goto VR_LangLoop
;
call Delay
;
return
;
;================================================
====================
VR_SetTimeout:
;
movlw CMD_TIMEOUT
;
movwf tx_data
;
call Send_tx
;
movlw D'3'
; 3 second
addlw ARG_ZERO
;
movwf tx_data
;
call Send_tx
;
movlw D'100'
;
movwf VCountHi
;
VR_SetTLoop: clrf VCountLo
;
call Get_rx
;
movlw STS_SUCCESS
; IF VRA = STS_SUCCESS THEN
subwf VRA,W
;
btfss STATUS,Z
;
goto VR_SetTLoop
;
call Delay
;
return
;
;================================================
====================
VR_Recognize:
;
movlw D'250'
;
movwf LED1_Tmr
;
;
Chk_WS:
movlw D'1'
;
47
subwf WS,W
btfss STATUS,C
goto WS_1
;
;
;
;
movlw D'3'
;
subwf WS,W
;
btfss STATUS,C
;
goto Chk_WSDone
;
;
WS_1:
movlw D'1'
;
movwf WS
;
Chk_WSDone: nop
;
;
movlw CMD_RECOG_SI
;
movwf tx_data
;
call Send_tx
;
movf WS,W
;
addlw ARG_ZERO
;
movwf tx_data
;
call Send_tx
;
;
movlw D'250'
;
movwf VCountHi
;
clrf VCountLo
;
call Get_rx
;
;
movlw STS_SIMILAR
; IF VRA = STS_SIMILAR
subwf VRA,W
;
btfss STATUS,Z
;
goto VR_RecgErr
;
;
movlw ARG_ACK
;
movwf tx_data
;
call Send_tx
;
;
clrf VCountHi
;
clrf VCountLo
;
call Get_rx
;
;
movlw ARG_MAX
;
subwf VRA,W
;
btfsc STATUS,C
;
goto VR_RecgErr
;
movlw ARG_ZERO
;
48
subwf VRA,W
;
btfss STATUS,C
;
goto VR_RecgErr
;
movwf I
;
incf I,F
;
;
Chk_WS1:
movlw D'1'
;
subwf WS,W
;
btfss STATUS,Z
;
goto VR_RecgOut
;
;
Chk_WS1Stop: movlw D'7'
;
subwf I,W
;
btfss STATUS,Z
;
goto Chk_WS1StopX
;
clrf I
;
goto VR_RecgOut
;
Chk_WS1StopX: nop
;
;
Chk_WS1Move: movlw D'2'
;
subwf I,W
;
btfss STATUS,Z
;
goto Chk_WS1MoveX
;
movlw D'2'
;
movwf WS
;
movlw D'250'
;
movwf LED2_Tmr
;
Chk_WS1MoveX: nop
;
;
goto VR_RecgDone
;
;
VR_RecgOut: movlw D'1'
;
movwf WS
;
movlw D'250'
;
movwf LED2_Tmr
;
;
VR_Recg0:
movlw D'0'
;
subwf I,W
;
btfsc STATUS,Z
;
call Move_Stop
;
;
VR_Recg1:
movlw D'1'
;
subwf I,W
;
btfsc STATUS,Z
;
49
call Turn_Left
VR_Recg2:
movlw D'2'
subwf I,W
btfsc STATUS,Z
call Turn_Right
VR_Recg3:
movlw D'3'
subwf I,W
btfsc STATUS,Z
call Move_UP
VR_Recg4:
movlw D'4'
subwf I,W
btfsc STATUS,Z
call Move_Down
VR_Recg5:
movlw D'5'
subwf I,W
btfsc STATUS,Z
call Move_FWD
VR_Recg6:
movlw D'6'
subwf I,W
btfsc STATUS,Z
call Move_BAK
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
goto VR_RecgDone
;
;
VR_RecgErr: movlw D'1'
;
movwf WS
;
;
VR_RecgDone: call Short_Delay
;
;
return
;
;================================================
====================
Send_tx:
bsf STATUS,RP0
;
btfss TXSTA,TRMT
; (1) if Transmit is Done
goto $-1
;
bcf STATUS,RP0
;
btfss PIR1,TXIF
;
goto $-1
; wait for transmitter interrupt flag
movf tx_data,W
;
50
movwf TXREG
; load data to be sent...
call Short_Delay
;
return
;
;================================================
====================
Get_rx:
clrf VRA
;
call Short_Delay
;
incf VCountLo,F
;
movlw D'250'
;
subwf VCountLo,W
;
btfss STATUS,C
;
goto Get_rx1
;
clrf VCountLo
;
decf VCountHi,F
;
movf VCountHi,W
;
btfsc STATUS,Z
;
goto Get_rxDone
;
Get_rx1:
call ser_in
; get UART input into W and rx_data
btfss is_data,0
;
goto Get_rx
; Check until
movf rx_data,W
;
movwf VRA
;
Get_rxDone: return
;
;================================================
====================
Do_LED1:
movf LED1_Tmr,W
;
btfsc STATUS,Z
;
goto Do_LED1OFF
;
bsf PORTC,4
;
decf LED1_Tmr,F
;
goto Do_LED1Done
;
;
Do_LED1OFF: movlw D'2'
;
subwf WS,W
;
btfss STATUS,Z
;
bcf PORTC,4
;
movlw D'2'
;
subwf WS,W
;
btfsc STATUS,Z
;
bsf PORTC,4
;
Do_LED1Done: return
;
;================================================
====================
Do_LED2:
movf LED2_Tmr,W
;
51
btfsc STATUS,Z
;
goto Do_LED2OFF
;
bsf PORTC,5
;
decf LED2_Tmr,F
;
goto Do_LED2Done
;
Do_LED2OFF: bcf PORTC,5
;
Do_LED2Done: return
;
;================================================
====================
Read_ADC:
bsf ADCON0,0
;
bsf ADCON0,7
;
nop
;
bsf ADCON0,2
;
nop
;
btfsc ADCON0,2
;
goto $-1
;
;
Read_ADC0: movlw D'0'
; RA0
subwf ADC_Sel,W
; Left Front Sensor
btfss STATUS,Z
;
goto Read_ADC0X
;
movf ADRESH,W
;
movwf ADC0
;
;
clrf Temp1
;
movlw D'80'
; 75cm equivalent
subwf ADC0,W
;
btfsc STATUS,C
;
bsf Temp1,0
;
btfsc Temp1,0
;
call Move_Stop
;
btfsc Temp1,0
;
bsf PORTD,0
;
btfss Temp1,0
;
bcf PORTD,0
;
;
Read_ADC0X: nop
;
;
Read_ADC1: movlw D'1'
; RA1
subwf ADC_Sel,W
; Right Front Sensor
btfss STATUS,Z
;
goto Read_ADC1X
;
movf ADRESH,W
;
movwf ADC1
;
52
;
;
clrf Temp1
movlw D'80'
subwf ADC1,W
btfsc STATUS,C
bsf Temp1,0
btfsc Temp1,0
call Move_Stop
btfsc Temp1,0
bsf PORTD,1
btfss Temp1,0
bcf PORTD,1
Read_ADC1X: nop
;
;
;
;
; 75cm equivalent
;
;
;
;
;
;
;
;
;
;
Read_ADC2: movlw D'2'
; RA2
subwf ADC_Sel,W
;
btfss STATUS,Z
;
goto Read_ADC2X
;
movf ADRESH,W
;
movwf ADC2
;
Read_ADC2X: nop
;
;
Read_ADC3: movlw D'3'
; RA3
subwf ADC_Sel,W
;
btfss STATUS,Z
;
goto Read_ADC3X
;
movf ADRESH,W
;
movwf ADC3
;
Read_ADC3X: nop
;
;
Read_ADC4: movlw D'4'
; RA5
subwf ADC_Sel,W
; Left Back Sensor
btfss STATUS,Z
;
goto Read_ADC4X
;
movf ADRESH,W
;
movwf ADC4
;
;
clrf Temp1
;
movlw D'80'
; 75cm equivalent
subwf ADC4,W
;
btfsc STATUS,C
;
bsf Temp1,0
;
;
btfsc Temp1,0
;
53
;
call
btfsc
bsf
btfss
bcf
Move_Stop
Temp1,0
PORTD,2
Temp1,0
PORTD,2
Read_ADC4X: nop
;
;
;
;
;
;
;
;
Read_ADC5: movlw D'5'
; RE0
subwf ADC_Sel,W
; Right Back Sensor
btfss STATUS,Z
;
goto Read_ADC5X
;
movf ADRESH,W
;
movwf ADC5
;
;
clrf Temp1
;
movlw D'80'
; 75cm equivalent
subwf ADC5,W
;
btfsc STATUS,C
;
bsf Temp1,0
;
;
btfsc Temp1,0
;
;
call Move_Stop
;
btfsc Temp1,0
;
bsf PORTD,3
;
btfss Temp1,0
;
bcf PORTD,3
;
;
Read_ADC5X: nop
;
;
Read_ADC6: movlw D'6'
; RE1
subwf ADC_Sel,W
; Left Floor Sensor
btfss STATUS,Z
;
goto Read_ADC6X
;
movf ADRESH,W
;
movwf ADC6
;
;
clrf Temp1
;
;
movlw D'60'
; 85cm equivalent
movlw D'50'
; ??cm equivalent
subwf ADC6,W
;
btfss STATUS,C
;
bsf Temp1,0
;
;
btfsc Temp1,0
;
;
call Move_Stop
;
54
btfsc
bsf
btfss
bcf
Temp1,0
PORTD,4
Temp1,0
PORTD,4
Read_ADC6X: nop
;
;
;
;
;
;
;
Read_ADC7: movlw D'7'
; RE2
subwf ADC_Sel,W
; Right Floor Sensor
btfss STATUS,Z
;
goto Read_ADC7X
;
movf ADRESH,W
;
movwf ADC7
;
;
clrf Temp1
;
;
movlw D'60'
; 85cm equivalent
movlw D'50'
; ??cm equivalent
subwf ADC7,W
;
btfss STATUS,C
;
;
bsf Temp1,0
;
;
btfsc Temp1,0
;
call Move_Stop
;
btfsc Temp1,0
;
bsf PORTD,5
;
btfss Temp1,0
;
bcf PORTD,5
;
;
Read_ADC7X: nop
;
;
movf PORTD,W
andlw B'00111111'
movwf Sensor
;
incf ADC_Sel,F
movlw D'8'
subwf ADC_Sel,W
btfsc STATUS,C
clrf ADC_Sel
;
Sel_ADC0:
movlw D'0'
subwf ADC_Sel,W
btfss STATUS,Z
;
;
;
;
;
;
;
;
;
;
;
55
goto Sel_ADC0X
movlw B'10000001'
movwf ADCON0
Sel_ADC0X: nop
;
Sel_ADC1:
movlw D'1'
subwf ADC_Sel,W
btfss STATUS,Z
goto Sel_ADC1X
movlw B'10001001'
movwf ADCON0
Sel_ADC1X: nop
;
Sel_ADC2:
movlw D'2'
subwf ADC_Sel,W
btfss STATUS,Z
goto Sel_ADC2X
movlw B'10010001'
movwf ADCON0
Sel_ADC2X: nop
;
Sel_ADC3:
movlw D'3'
subwf ADC_Sel,W
btfss STATUS,Z
goto Sel_ADC3X
movlw B'10011001'
movwf ADCON0
Sel_ADC3X: nop
;
Sel_ADC4:
movlw D'4'
subwf ADC_Sel,W
btfss STATUS,Z
goto Sel_ADC4X
movlw B'10100001'
movwf ADCON0
Sel_ADC4X: nop
;
Sel_ADC5:
movlw D'5'
subwf ADC_Sel,W
btfss STATUS,Z
goto Sel_ADC5X
movlw B'10101001'
movwf ADCON0
Sel_ADC5X: nop
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
56
;
Sel_ADC6:
movlw D'6'
;
subwf ADC_Sel,W
;
btfss STATUS,Z
;
goto Sel_ADC6X
;
movlw B'10110001'
;
movwf ADCON0
;
Sel_ADC6X: nop
;
;
Sel_ADC7:
movlw D'7'
;
subwf ADC_Sel,W
;
btfss STATUS,Z
;
goto Sel_ADC7X
;
movlw B'10111001'
;
movwf ADCON0
;
Sel_ADC7X: nop
;
;
Read_ADCX: return
;
;================================================
====================
Read_SW:
movf PORTA,W
;
movwf SWA_New
;
;
Chk_SWA4:
btfsc SWA_New,4
;
goto Chk_SWA4Done
;
call Move_Stop
;
Chk_SWA4Done: nop
;
;
;Chk_SWA0:
btfsc SWA_New,0
;
;
goto Chk_SWA0Done
;
;
call Move_Stop
;
;Chk_SWA0Done: nop
;
;
;
;Chk_SWA1:
btfsc SWA_New,1
;
;
goto Chk_SWA1Done
;
;
btfss SWA_Prev,1
;
;
goto Chk_SWA1Done
;
;
call Move_FWD
;
;Chk_SWA1Done: nop
;
;
;
;Chk_SWA2:
btfsc SWA_New,2
;
;
goto Chk_SWA2Done
;
;
btfss SWA_Prev,2
;
;
goto Chk_SWA2Done
;
57
;
call Turn_Right
;
;Chk_SWA2Done: nop
;
;
;Chk_SWA3:
btfsc SWA_New,3
;
goto Chk_SWA3Done
;
btfss SWA_Prev,3
;
;
goto Chk_SWA3Done
;
call Turn_Left
;
;Chk_SWA3Done: nop
;
;
;Chk_SWA4:
btfsc SWA_New,4
;
goto Chk_SWA4Done
;
btfss SWA_Prev,4
;
;
goto Chk_SWA4Done
;
call Move_BAK
;
;Chk_SWA4Done: nop
;
;
;Chk_SWA5:
btfsc SWA_New,5
;
goto Chk_SWA5Done
;
btfss SWA_Prev,5
;
;
goto Chk_SWA5Done
;
call Move_Down
;
;Chk_SWA5Done: nop
;
;
;Chk_SWE0:
btfsc SWE_New,0
;
goto Chk_SWE0Done
;
btfss SWE_Prev,0
;
;
goto Chk_SWE0Done
;
call Move_UP
;
;Chk_SWE0Done: nop
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
Chk_FWD:
movf PORTB,W
;
andlw H'0F'
;
sublw B'00000101'
;
btfss STATUS,Z
;
goto Chk_FWDX
;
btfsc Sensor,0
;Left Front
call Move_Stop
;
btfsc Sensor,1
;Right Front
call Move_Stop
;
btfsc Sensor,4
;Left Floor
call Move_Stop
;
btfsc Sensor,5
;Right Floor
58
call Move_Stop
Chk_FWDX:
nop
;
;
;
movf PORTB,W
;
andlw H'0F'
;
sublw B'00001010'
;
btfss STATUS,Z
;
goto Chk_BAKX
;
btfsc Sensor,2
;Left Back
call Move_Stop
;
btfsc Sensor,3
;Right Back
call Move_Stop
;
Chk_BAKX:
nop
;
;
Chk_Left:
movf PORTB,W
;
andlw H'0F'
;
sublw B'00000110'
;
btfss STATUS,Z
;
goto Chk_LeftX
;
btfsc Sensor,0
;Left Front
call Move_Stop
;
btfsc Sensor,4
;Left Floor
call Move_Stop
;
Chk_LeftX: nop
;
;
Chk_Right: movf PORTB,W
;
andlw H'0F'
;
sublw B'00001001'
;
btfss STATUS,Z
;
goto Chk_RightX
;
btfsc Sensor,1
;Right Front
call Move_Stop
;
btfsc Sensor,5
;Right Floor
call Move_Stop
;
Chk_RightX: nop
;
;
movf SWA_New,W
;
movwf SWA_Prev
;
movf SWE_New,W
;
movwf SWE_Prev
;
return
;
;================================================
====================
Move_Stop: bcf PORTB,0
;
Chk_BAK:
59
bcf PORTB,1
bcf PORTB,2
bcf PORTB,3
bcf PORTB,4
bcf PORTB,5
bcf PORTB,6
bcf PORTB,7
call Relay_Delay
return
;
;
Move_FWD:
bcf PORTB,1
bcf PORTB,3
bcf PORTB,7
call Relay_Delay
bsf PORTB,0
bsf PORTB,2
bsf PORTB,6
return
;
;
Move_BAK:
bcf PORTB,0
bcf PORTB,2
bcf PORTB,6
call Relay_Delay
bsf PORTB,1
bsf PORTB,3
bsf PORTB,7
return
;
;
Move_Left: bcf PORTB,1
bcf PORTB,2
bcf PORTB,3
bcf PORTB,6
bcf PORTB,7
call Relay_Delay
bsf PORTB,2
return
;
;
Move_Right: bcf PORTB,0
bcf PORTB,1
bcf PORTB,3
bcf PORTB,6
bcf PORTB,7
call Relay_Delay
bsf PORTB,0
;
;
;
;
;
;
;
;
;
;
;
; 76543210
; 01 0101
;
;
;
;
;
; 76543210
; 10 1010
;
;
;
;
;
;
;
; 76543210
; 00 0100
;
;
;
;
;
; 76543210
;
60
return
;
;
Turn_Left: bcf PORTB,1
;
bcf PORTB,2
;
bcf PORTB,6
;
bcf PORTB,7
;
call Relay_Delay
; 76543210
bsf PORTB,1
; 00 0110
bsf PORTB,2
;
return
;
;
Turn_Right: bcf PORTB,0
;
bcf PORTB,3
;
bcf PORTB,6
;
bcf PORTB,7
;
call Relay_Delay
; 76543210
bsf PORTB,0
; 00 1001
bsf PORTB,3
;
return
;
;
Move_UP:
bcf PORTB,0
;
bcf PORTB,1
;
bcf PORTB,2
;
bcf PORTB,3
;
bcf PORTB,6
;
bcf PORTB,7
;
bcf PORTB,4
;
call Relay_Delay
; 76543210
bsf PORTB,5
; 10
return
;
;
Move_Down: bcf PORTB,0
;
bcf PORTB,1
;
bcf PORTB,2
;
bcf PORTB,3
;
bcf PORTB,6
;
bcf PORTB,7
;
bcf PORTB,5
;
call Relay_Delay
; 76543210
bsf PORTB,4
; 01
return
;
;================================================
====================
Relay_Delay: movlw D'250'
;
61
movwf I
;
RDly_Loop: decf I,F
;
movf I,W
;
btfss STATUS,Z
;
goto RDly_Loop
;
return
;
;================================================
====================
Short_Delay: movlw D'250'
;
movwf I
;
SDly_Loop: decf I,F
;
movf I,W
;
btfss STATUS,Z
;
goto SDly_Loop
;
call Do_LED1
;
call Do_LED2
;
call Read_SW
;
call Read_ADC
;
return
;
;================================================
====================
Delay:
movlw D'100'
;
movwf J
;
Dly_Loop1: call Short_Delay
;
decf J,F
;
movf J,W
;
btfss STATUS,Z
;
goto Dly_Loop1
;
return
;
;================================================
===================
;
CONFIGURE SERIAL PORT
;================================================
===================
Init_UART:
;uart specific initialization
;txsta=Transmit STAtus and control reg.
bsf STATUS,RP0
;Select Bank 1
bcf STATUS,RP1
;
;
bcf TXSTA,CSRC
; <7> (0) don't care in asynch mode
bcf TXSTA,TX9
; <6> 0 select 8 bit mode
bsf TXSTA,TXEN
; <5> 1 enable transmit function
;
*MUST* be 1 for transmit to work!!!
bcf TXSTA,SYNC
; <4> 0 asynchronous mode.
62
;
*MUST* be 0 !!!
;
If NOT 0 the async mode is NOT selected!
; <3> (0) not implemented
;================================================
===================
bsf TXSTA,BRGH
; <2> 1 ENABLE high baud rate generator !!!
;
0 DISABLE High Baud Rate Generator
;================================================
===================
; <1> (0) trmt is read only.
bcf TXSTA,TX9D
; <0> (0) tx9d data cleared to 0.
;baudrate
=
d'9600'
;desired baudrate.
spbrg_value =
d'103'
; for BRGH = 1 (see TABLE 10-3 of
30292c.pdf)
; @16Mhz Crystal
;
movlw spbrg_value
;set baud rate generator value
movwf SPBRG
;
;*****************************************************************
***********
bcf STATUS,RP0
;allow access to page 0 stuff again. (normal)
;more uart specific initializat4ion
;rcsta=ReCeive STAtus and control register
bsf RCSTA,SPEN
; 7 spen 1=rx/tx set for serial uart mode
; !!! very important to set spen=1
bcf RCSTA,RX9
; 6 rc8/9 0=8 bit mode
bcf RCSTA,SREN
; 5 sren 0=don't care in uart mode
bsf RCSTA,CREN
; 4 cren 1=enable constant reception
;!!! (and low clears errors)
; 3 not used / 0 / don't care
bcf RCSTA,FERR
; 2 ferr input framing error bit. 1=error
; 1 oerr input overrun error bit. 1=error
;It is only cleared when you pulse cren low.
bcf RCSTA,RX9D
; 0 rx9d input (9th data bit). ignore.
;
movf RCREG,W
;clear uart receiver
movf RCREG,W
; including fifo
movf RCREG,W
; which is three deep.
;
movlw 0
;any character will do.
movwf TXREG
;send out dummy character
; to get transmit flag valid!
return
;
;*****************************************************************
**********
63
;
RS-232 SERIAL IN / SERIAL OUT ROUTINES
;*****************************************************************
**********
;exit with received serial data in W and in variable rx_data
ser_in:
clrf is_data
;Reset Flag
btfsc RCSTA,OERR
;
goto overerror
;if overflow error...
btfsc RCSTA,FERR
;
goto frameerror
;if framing error...
;
clrw
;
uart_ready: btfss PIR1,RCIF
;
goto ser_inX
;
movf RCREG,W
;recover uart data
movwf rx_data
;save for later
bsf is_data,0
;
ser_inX:
return
;
;
overerror: bcf RCSTA,CREN
;pulse cren off...
movf RCREG,W
;flush fifo
movf RCREG,W
; all three elements.
movf RCREG,W
;
bsf RCSTA,CREN
;turn cren back on.
;this pulsing of cren
;will clear the oerr flag.
goto ser_inX
;try again...
;
frameerror: movf RCREG,W
;reading rcreg clears ferr flag.
goto ser_inX
;try again...
;*****************************************************************
**********
end
;
;*****************************************************************
***********
64
PIC16F87X
28/40-Pin 8-Bit CMOS FLASH Microcontrollers
Devices Included in this Data Sheet:
PDIP
• PIC16F876
• PIC16F877
Microcontroller Core Features:
• High performance RISC CPU
• Only 35 single word instructions to learn
• All single cycle instructions except for program
branches which are two cycle
• Operating speed: DC - 20 MHz clock input
DC - 200 ns instruction cycle
• Up to 8K x 14 words of FLASH Program Memory,
Up to 368 x 8 bytes of Data Memory (RAM)
Up to 256 x 8 bytes of EEPROM Data Memory
• Pinout compatible to the PIC16C73B/74B/76/77
• Interrupt capability (up to 14 sources)
• Eight level deep hardware stack
• Direct, indirect and relative addressing modes
• Power-on Reset (POR)
• Power-up Timer (PWRT) and
Oscillator Start-up Timer (OST)
• Watchdog Timer (WDT) with its own on-chip RC
oscillator for reliable operation
• Programmable code protection
• Power saving SLEEP mode
• Selectable oscillator options
• Low power, high speed CMOS FLASH/EEPROM
technology
• Fully static design
• In-Circuit Serial Programming (ICSP) via two
pins
• Single 5V In-Circuit Serial Programming capability
• In-Circuit Debugging via two pins
• Processor read/write access to program memory
• Wide operating voltage range: 2.0V to 5.5V
• High Sink/Source Current: 25 mA
• Commercial, Industrial and Extended temperature
ranges
• Low-power consumption:
- < 0.6 mA typical @ 3V, 4 MHz
- 20 µA typical @ 3V, 32 kHz
- < 1 µA typical standby current
MCLR/VPP
RA0/AN0
1
2
40
39
RB7/PGD
RB6/PGC
RA1/AN1
RA2/AN2/VREF-
3
38
RB5
4
37
RA3/AN3/VREF+
RA4/T0CKI
5
6
36
35
RB4
RB3/PGM
RB2
RA5/AN4/SS
7
34
RB1
RE0/RD/AN5
RE1/WR/AN6
8
33
RB0/INT
VDD
9
10
RE2/CS/AN7
VDD
VSS
11
12
PIC16F877/874
• PIC16F873
• PIC16F874
Pin Diagram
32
31
VSS
OSC1/CLKIN
13
OSC2/CLKOUT
14
27
RD7/PSP7
RD6/PSP6
RD5/PSP5
RD4/PSP4
RC0/T1OSO/T1CKI
RC1/T1OSI/CCP2
15
16
26
25
RC7/RX/DT
RC6/TX/CK
RC2/CCP1
17
24
RC5/SDO
RC3/SCK/SCL
RD0/PSP0
18
23
19
20
22
21
RC4/SDI/SDA
RD3/PSP3
RD1/PSP1
30
29
28
RD2/PSP2
Peripheral Features:
• Timer0: 8-bit timer/counter with 8-bit prescaler
• Timer1: 16-bit timer/counter with prescaler,
can be incremented during SLEEP via external
crystal/clock
• Timer2: 8-bit timer/counter with 8-bit period
register, prescaler and postscaler
• Two Capture, Compare, PWM modules
- Capture is 16-bit, max. resolution is 12.5 ns
- Compare is 16-bit, max. resolution is 200 ns
- PWM max. resolution is 10-bit
• 10-bit multi-channel Analog-to-Digital converter
• Synchronous Serial Port (SSP) with SPI (Master
mode) and I2C (Master/Slave)
• Universal Synchronous Asynchronous Receiver
Transmitter (USART/SCI) with 9-bit address
detection
• Parallel Slave Port (PSP) 8-bits wide, with
external RD, WR and CS controls (40/44-pin only)
• Brown-out detection circuitry for
Brown-out Reset (BOR)
64
PIC16F87X
Pin Diagrams
PDIP, SOIC
RB7/PGD
RB6/PGC
RB5
RB4
RB3/PGM
RB2
RB1
RB0/INT
VDD
VSS
RC7/RX/DT
RC6/TX/CK
PLCC
44
43
42
41
40
39
38
37
36
35
34
QFP
PIC16F877
PIC16F874
33
32
31
30
29
28
27
26
25
24
23
12
13
14
15
16
17
18
19
20
21
22
1
2
3
4
5
6
7
8
9
10
11
NC
RC0/T1OSO/T1CKI
OSC2/CLKOUT
OSC1/CLKIN
VSS
VDD
RE2/AN7/CS
RE1/AN6/WR
RE0/AN5/RD
RA5/AN4/SS
RA4/T0CKI
NC
NC
RB4
RB5
RB6/PGC
RB7/PGD
MCLR/VPP
RA0/AN0
RA1/AN1
RA2/AN2/VREFRA3/AN3/VREF+
RC7/RX/DT
RD4/PSP4
RD5/PSP5
RD6/PSP6
RD7/PSP7
VSS
VDD
RB0/INT
RB1
RB2
RB3/PGM
7
8
9
10
11
12
13
14
15
16
17
PIC16F877
PIC16F874
39
38
37
36
35
34
33
32
31
30
29
RC1/T1OSI/CCP2
RC2/CCP1
RC3/SCK/SCL
RD0/PSP0
RD1/PSP1
RD2/PSP2
RD3/PSP3
RC4/SDI/SDA
RC5/SDO
RC6/TX/CK
NC
RC6/TX/CK
RC5/SDO
RC4/SDI/SDA
RD3/PSP3
RD2/PSP2
RD1/PSP1
RD0/PSP0
RC3/SCK/SCL
RC2/CCP1
RC1/T1OSI/CCP2
NC
RA4/T0CKI
RA5/AN4/SS
RE0/RD/AN5
RE1/WR/AN6
RE2/CS/AN7
VDD
VSS
OSC1/CLKIN
OSC2/CLKOUT
RC0/T1OSO/T1CK1
NC
RA3/AN3/VREF+
RA2/AN2/VREFRA1/AN1
RA0/AN0
MCLR/VPP
NC
RB7/PGD
RB6/PGC
RB5
RB4
NC
RC5/SDO
RC4/SDI/SDA
6
5
4
3
2
1
44
43
42
41
40
28
27
26
25
24
23
22
21
20
19
18
17
16
15
18
19
20
21
22
23
24
25
26
27
28
PIC16F876/873
MCLR/VPP
RA0/AN0
RA1/AN1
RA2/AN2/VREFRA3/AN3/VREF+
RA4/T0CKI
RA5/AN4/SS
VSS
OSC1/CLKIN
OSC2/CLKOUT
RC0/T1OSO/T1CKI
RC1/T1OSI/CCP2
RC2/CCP1
RC3/SCK/SCL
65
RB3/PGM
RB2
RB1
RB0/INT
VDD
VSS
RD7/PSP7
RD6/PSP6
RD5/PSP5
RD4/PSP4
RC7/RX/DT
PIC16F87X
Key Features PICmicro™ MidRange Reference Manual
(DS33023)
PIC16F873
PIC16F874
PIC16F876
PIC16F877
Operating Frequency
DC - 20 MHz
DC - 20 MHz
DC - 20 MHz
DC - 20 MHz
RESETS (and Delays)
POR, BOR
(PWRT, OST)
POR, BOR
(PWRT, OST)
POR, BOR
(PWRT, OST)
POR, BOR
(PWRT, OST)
FLASH Program Memory
(14-bit words)
4K
4K
8K
8K
Data Memory (bytes)
192
192
368
368
EEPROM Data Memory
128
128
256
256
Interrupts
13
14
13
14
I/O Ports
Ports A,B,C
Ports A,B,C,D,E
Ports A,B,C
Ports A,B,C,D,E
Timers
3
3
3
3
Capture/Compare/PWM Modules
2
2
2
2
Serial Communications
MSSP, USART
MSSP, USART
MSSP, USART
MSSP, USART
Parallel Communications
—
PSP
—
PSP
10-bit Analog-to-Digital Module
5 input channels
8 input channels
5 input channels
8 input channels
Instruction Set
35 instructions
35 instructions
35 instructions
35 instructions
66
PIC16F87X
TABLE 1-2:
PIC16F874 AND PIC16F877 PINOUT DESCRIPTION
DIP
Pin#
PLCC
Pin#
QFP
Pin#
I/O/P
Type
Buffer
Type
OSC1/CLKIN
13
14
30
I
ST/CMOS(4)
OSC2/CLKOUT
14
15
31
O
—
Oscillator crystal output. Connects to crystal or resonator
in crystal oscillator mode. In RC mode, OSC2 pin outputs
CLKOUT which has 1/4 the frequency of OSC1, and
denotes the instruction cycle rate.
MCLR/VPP
1
2
18
I/P
ST
Master Clear (Reset) input or programming voltage input.
This pin is an active low RESET to the device.
RA0/AN0
2
3
19
I/O
TTL
RA1/AN1
3
4
20
I/O
TTL
RA1 can also be analog input1.
RA2/AN2/VREF-
4
5
21
I/O
TTL
RA2 can also be analog input2 or negative
analog reference voltage.
RA3/AN3/VREF+
5
6
22
I/O
TTL
RA3 can also be analog input3 or positive
analog reference voltage.
RA4/T0CKI
6
7
23
I/O
ST
RA4 can also be the clock input to the Timer0 timer/
counter. Output is open drain type.
RA5/SS/AN4
7
8
24
I/O
TTL
RA5 can also be analog input4 or the slave select for
the synchronous serial port.
Pin Name
Description
Oscillator crystal input/external clock source input.
PORTA is a bi-directional I/O port.
RA0 can also be analog input0.
PORTB is a bi-directional I/O port. PORTB can be software programmed for internal weak pull-up on all inputs.
RB0/INT
33
36
8
I/O
TTL/ST(1)
RB1
34
37
9
I/O
TTL TTL
RB2
35
38
10
I/O
TTL TTL
RB3/PGM
36
39
11
I/O
TTL
TTL/ST(2)
RB4
37
41
14
I/O
RB5
38
42
15
I/O
RB6/PGC
39
43
16
I/O
RB7/PGD
40
44
17
I/O
4:
RB3 can also be the low voltage programming input.
Interrupt-on-change pin.
Interrupt-on-change pin.
TTL/ST(2)
Interrupt-on-change pin or In-Circuit Debugger pin.
Serial programming clock.
Interrupt-on-change pin or In-Circuit Debugger pin.
Serial programming data.
Legend: I = input
Note 1:
2:
3:
RB0 can also be the external interrupt pin.
O = output
I/O = input/output
P = power
— = Not used
TTL = TTL input
ST = Schmitt Trigger input
This buffer is a Schmitt Trigger input when configured as an external interrupt.
This buffer is a Schmitt Trigger input when used in Serial Programming mode.
This buffer is a Schmitt Trigger input when configured as general purpose I/O and a TTL input when used in the Parallel
Slave Port mode (for interfacing to a microprocessor bus).
This buffer is a Schmitt Trigger input when configured in RC oscillator mode and a CMOS input otherwise.
67
PIC16F87X
TABLE 1-2:
PIC16F874 AND PIC16F877 PINOUT DESCRIPTION (CONTINUED)
Pin Name
DIP
Pin#
PLCC
Pin#
QFP
Pin#
I/O/P
Type
Buffer
Type
RC0/T1OSO/T1CKI
15
16
32
I/O
ST
RC0 can also be the Timer1 oscillator output or a
Timer1 clock input.
RC1/T1OSI/CCP2
16
18
35
I/O
ST
RC1 can also be the Timer1 oscillator input or
Capture2 input/Compare2 output/PWM2 output.
RC2/CCP1
17
19
36
I/O
ST
RC2 can also be the Capture1 input/Compare1
output/PWM1 output.
RC3/SCK/SCL
18
20
37
I/O
ST
RC3 can also be the synchronous serial clock input/
output for both SPI and I2C modes.
RC4/SDI/SDA
23
25
42
I/O
ST
RC4 can also be the SPI Data In (SPI mode) or
data I/O (I2C mode).
RC5/SDO
24
26
43
I/O
ST
RC5 can also be the SPI Data Out (SPI mode).
RC6/TX/CK
25
27
44
I/O
ST
RC6 can also be the USART Asynchronous Transmit
or Synchronous Clock.
RC7/RX/DT
26
29
1
I/O
ST
RC7 can also be the USART Asynchronous Receive
or Synchronous Data.
Description
PORTC is a bi-directional I/O port.
PORTD is a bi-directional I/O port or parallel slave port
when interfacing to a microprocessor bus.
RD0/PSP0
19
21
38
I/O
ST/TTL(3)
RD1/PSP1
20
22
39
I/O
ST/TTL(3)
RD2/PSP2
21
23
40
I/O
ST/TTL(3)
RD3/PSP3
22
24
41
I/O
ST/TTL(3)
RD4/PSP4
27
30
2
I/O
ST/TTL(3)
RD5/PSP5
28
31
3
I/O
ST/TTL(3)
RD6/PSP6
29
32
4
I/O
ST/TTL(3)
RD7/PSP7
30
33
5
I/O
ST/TTL(3)
RE0/RD/AN5
8
9
25
I/O
ST/TTL(3)
RE0 can also be read control for the parallel slave
port, or analog input5.
RE1/WR/AN6
9
10
26
I/O
ST/TTL(3)
RE1 can also be write control for the parallel slave
port, or analog input6.
RE2/CS/AN7
10
11
27
I/O
ST/TTL(3)
VSS
12,31
13,34
6,29
P
—
Ground reference for logic and I/O pins.
VDD
11,32
12,35
7,28
P
—
Positive supply for logic and I/O pins.
NC
—
1,17,28,
40
12,13,
33,34
—
These pins are not internally connected. These pins
should be left unconnected.
PORTE is a bi-directional I/O port.
Legend: I = input
Note 1:
2:
3:
4:
RE2 can also be select control for the parallel slave
port, or analog input7.
O = output
I/O = input/output
P = power
— = Not used
TTL = TTL input
ST = Schmitt Trigger input
This buffer is a Schmitt Trigger input when configured as an external interrupt.
This buffer is a Schmitt Trigger input when used in Serial Programming mode.
This buffer is a Schmitt Trigger input when configured as general purpose I/O and a TTL input when used in the Parallel
Slave Port mode (for interfacing to a microprocessor bus).
This buffer is a Schmitt Trigger input when configured in RC oscillator mode and a CMOS input otherwise.
68
PIC16F87X
3.0
FIGURE 3-1:
I/O PORTS
Some pins for these I/O ports are multiplexed with an
alternate function for the peripheral features on the
device. In general, when a peripheral is enabled, that
pin may not be used as a general purpose I/O pin.
Data
Bus
WR
Port
Additional information on I/O ports may be found in the
PICmicro™ Mid-Range Reference Manual, (DS33023).
3.1
WR
TRIS
MOVWF
TRISA
I/O pin(1)
N
Q
VSS
Analog
Input
Mode
Q
CK
TTL
Input
Buffer
D
To A/D Converter
Note 1: I/O pins have protection diodes to VDD and VSS.
FIGURE 3-2:
Data
Bus
WR
Port
BLOCK DIAGRAM OF
RA4/T0CKI PIN
Data Latch
D
Q
CK
Q
N
TRIS Latch
INITIALIZING PORTA
STATUS, RP0
0x06
ADCON1
0xCF
P
RD Port
The TRISA register controls the direction of the RA
pins, even when they are being used as analog inputs.
The user must ensure the bits in the TRISA register are
maintained set when using them as analog inputs.
BSF
MOVLW
MOVWF
MOVLW
Q
CK
EN
On a Power-on Reset, these pins are configured as analog inputs and read as '0'.
;
;
;
;
;
;
;
;
;
;
;
;
;
;
;
VDD
Q
Other PORTA pins are multiplexed with analog inputs
and analog VREF input. The operation of each pin is
selected by clearing/setting the control bits in the
ADCON1 register (A/D Control Register1).
STATUS, RP0
STATUS, RP1
PORTA
Q
RD
TRIS
Pin RA4 is multiplexed with the Timer0 module clock
input to become the RA4/T0CKI pin. The RA4/T0CKI
pin is a Schmitt Trigger input and an open drain output.
All other PORTA pins have TTL input levels and full
CMOS output drivers.
BCF
BCF
CLRF
D
D
Reading the PORTA register reads the status of the
pins, whereas writing to it will write to the port latch. All
write operations are read-modify-write operations.
Therefore, a write to a port implies that the port pins are
read, the value is modified and then written to the port
data latch.
EXAMPLE 3-1:
Data Latch
TRIS Latch
PORTA and the TRISA Register
PORTA is a 6-bit wide, bi-directional port. The corresponding data direction register is TRISA. Setting a
TRISA bit (= 1) will make the corresponding PORTA pin
an input (i.e., put the corresponding output driver in a
Hi-Impedance mode). Clearing a TRISA bit (= 0) will
make the corresponding PORTA pin an output (i.e., put
the contents of the output latch on the selected pin).
Note:
BLOCK DIAGRAM OF
RA3:RA0 AND RA5 PINS
WR
TRIS
Bank0
Initialize PORTA by
clearing output
data latches
Select Bank 1
Configure all pins
as digital inputs
Value used to
initialize data
direction
Set RA<3:0> as inputs
RA<5:4> as outputs
TRISA<7:6>are always
read as ’0’.
D
Q
CK
Q
VSS
Schmitt
Trigger
Input
Buffer
RD
TRIS
Q
D
ENEN
RD Port
TMR0 Clock Input
Note 1: I/O pin has protection diodes to VSS only.
69
I/O pin(1)
PIC16F87X
TABLE 3-1:
PORTA FUNCTIONS
Name
Bit#
Buffer
Function
RA0/AN0
bit0
TTL
Input/output or analog input.
RA1/AN1
bit1
TTL
Input/output or analog input.
RA2/AN2
bit2
TTL
Input/output or analog input.
RA3/AN3/VREF
bit3
TTL
Input/output or analog input or VREF.
RA4/T0CKI
bit4
ST
Input/output or external clock input for Timer0. Output is open drain type.
RA5/SS/AN4
bit5
TTL
Input/output or slave select input for synchronous serial port or analog input.
Legend: TTL = TTL input, ST = Schmitt Trigger input
TABLE 3-2:
Address
SUMMARY OF REGISTERS ASSOCIATED WITH PORTA
Name
Bit 7
Bit 6
05h
PORTA
—
—
85h
TRISA
—
—
9Fh
ADCON1 ADFM
—
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on: Value on all
POR,
other
BOR
RESETS
RA5
RA4
RA3
RA2
RA1
RA0
--0x 0000
--0u 0000
--11 1111
--11 1111
PCFG3 PCFG2 PCFG1 PCFG0 --0- 0000
--0- 0000
PORTA Data Direction Register
—
—
Legend: x = unknown, u = unchanged, - = unimplemented locations read as '0'.
Shaded cells are not used by PORTA.
Note:
When using the SSP module in SPI Slave mode and SS enabled, the A/D converter must be set to one of
the following modes, where PCFG3:PCFG0 = 0100,0101, 011x, 1101, 1110, 1111.
70
PIC16F87X
3.2
PORTB and the TRISB Register
This interrupt can wake the device from SLEEP. The
user, in the Interrupt Service Routine, can clear the
interrupt in the following manner:
PORTB is an 8-bit wide, bi-directional port. The corresponding data direction register is TRISB. Setting a
TRISB bit (= 1) will make the corresponding PORTB pin
an input (i.e., put the corresponding output driver in a
Hi-Impedance mode). Clearing a TRISB bit (= 0) will
make the corresponding PORTB pin an output (i.e., put
the contents of the output latch on the selected pin).
a)
b)
A mismatch condition will continue to set flag bit RBIF.
Reading PORTB will end the mismatch condition and
allow flag bit RBIF to be cleared.
Three pins of PORTB are multiplexed with the Low
Voltage Programming function: RB3/PGM, RB6/PGC
and RB7/PGD. The alternate functions of these pins
are described in the Special Features Section.
The interrupt-on-change feature is recommended for
wake-up on key depression operation and operations
where PORTB is only used for the interrupt-on-change
feature. Polling of PORTB is not recommended while
using the interrupt-on-change feature.
Each of the PORTB pins has a weak internal pull-up. A
single control bit can turn on all the pull-ups. This is performed by clearing bit RBPU (OPTION_REG<7>). The
weak pull-up is automatically turned off when the port
pin is configured as an output. The pull-ups are disabled on a Power-on Reset.
FIGURE 3-3:
This interrupt-on-mismatch feature, together with software configureable pull-ups on these four pins, allow
easy interface to a keypad and make it possible for
wake-up on key depression. Refer to the Embedded
Control Handbook, “Implementing Wake-up on Key
Strokes” (AN552).
BLOCK DIAGRAM OF
RB3:RB0 PINS
RB0/INT is an external interrupt input pin and is configured using the INTEDG bit (OPTION_REG<6>).
VDD
RBPU(2)
Data Bus
WR Port
Weak
P Pull-up
RB0/INT is discussed in detail in Section 12.10.1.
Data Latch
D
FIGURE 3-4:
Q
BLOCK DIAGRAM OF
RB7:RB4 PINS
I/O
pin(1)
CK
VDD
TRIS Latch
D
Q
WR TRIS
Any read or write of PORTB. This will end the
mismatch condition.
Clear flag bit RBIF.
RBPU(2)
TTL
Input
Buffer
CK
Data Bus
Weak
P Pull-up
Data Latch
D
Q
WR Port
I/O
pin(1)
CK
RD TRIS
Q
TRIS Latch
D
Q
D
RD Port
WR TRIS
EN
RB0/INT
RB3/PGM
TTL
Input
Buffer
CK
RD TRIS
Schmitt Trigger
Buffer
RD Port
ST
Buffer
Latch
Q
D
RD Port
Note 1: I/O pins have diode protection to VDD and VSS.
EN
Q1
Set RBIF
2: To enable weak pull-ups, set the appropriate TRIS
bit(s) and clear the RBPU bit (OPTION_REG<7>).
Q
Four of the PORTB pins, RB7:RB4, have an interrupton-change feature. Only pins configured as inputs can
cause this interrupt to occur (i.e., any RB7:RB4 pin
configured as an output is excluded from the interrupton-change comparison). The input pins (of RB7:RB4)
are compared with the old value latched on the last
read of PORTB. The “mismatch” outputs of RB7:RB4
are OR’ed together to generate the RB Port Change
Interrupt with flag bit RBIF (INTCON<0>).
From other
RB7:RB4 pins
D
RD Port
EN
Q3
RB7:RB6
In Serial Programming Mode
Note 1: I/O pins have diode protection to VDD and VSS.
2: To enable weak pull-ups, set the appropriate TRIS
bit(s) and clear the RBPU bit (OPTION_REG<7>).
71
PIC16F87X
TABLE 3-3:
Name
PORTB FUNCTIONS
Bit#
Buffer
RB0/INT
bit0
TTL/ST(1)
RB1
bit1
TTL
Input/output pin. Internal software programmable weak pull-up.
RB2
bit2
TTL
Input/output pin. Internal software programmable weak pull-up.
RB3/PGM(3)
bit3
TTL
Input/output pin or programming pin in LVP mode. Internal software
programmable weak pull-up.
RB4
bit4
TTL
Input/output pin (with interrupt-on-change). Internal software programmable
weak pull-up.
RB5
bit5
TTL
Input/output pin (with interrupt-on-change). Internal software programmable
weak pull-up.
RB6/PGC
bit6
TTL/ST(2)
Input/output pin (with interrupt-on-change) or In-Circuit Debugger pin.
Internal software programmable weak pull-up. Serial programming clock.
RB7/PGD
bit7
TTL/ST(2)
Input/output pin (with interrupt-on-change) or In-Circuit Debugger pin.
Internal software programmable weak pull-up. Serial programming data.
Legend:
Note 1:
2:
3:
Function
Input/output pin or external interrupt input. Internal software
programmable weak pull-up.
TTL = TTL input, ST = Schmitt Trigger input
This buffer is a Schmitt Trigger input when configured as the external interrupt.
This buffer is a Schmitt Trigger input when used in Serial Programming mode.
Low Voltage ICSP Programming (LVP) is enabled by default, which disables the RB3 I/O function. LVP
must be disabled to enable RB3 as an I/O pin and allow maximum compatibility to the other 28-pin and
40-pin mid-range devices.
TABLE 3-4:
Address
SUMMARY OF REGISTERS ASSOCIATED WITH PORTB
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3 Bit 2 Bit 1 Bit 0
RB7
RB6
RB5
RB4
RB3
06h, 106h
PORTB
86h, 186h
TRISB
81h, 181h
OPTION_REG RBPU
RB2
RB1
T0CS T0SE
1111 1111 1111 1111
PSA
PS2
Legend: x = unknown, u = unchanged. Shaded cells are not used by PORTB.
72
Value on
all other
RESETS
RB0 xxxx xxxx uuuu uuuu
PORTB Data Direction Register
INTEDG
Value on:
POR,
BOR
PS1
PS0
1111 1111 1111 1111
PIC16F87X
3.3
FIGURE 3-6:
PORTC and the TRISC Register
PORTC is an 8-bit wide, bi-directional port. The corresponding data direction register is TRISC. Setting a
TRISC bit (= 1) will make the corresponding PORTC
pin an input (i.e., put the corresponding output driver in
a Hi-Impedance mode). Clearing a TRISC bit (= 0) will
make the corresponding PORTC pin an output (i.e., put
the contents of the output latch on the selected pin).
Port/Peripheral Select(2)
Peripheral Data Out
Data Bus
WR
Port
PORTC is multiplexed with several peripheral functions
(Table 3-5). PORTC pins have Schmitt Trigger input
buffers.
WR
TRIS
When enabling peripheral functions, care should be
taken in defining TRIS bits for each PORTC pin. Some
peripherals override the TRIS bit to make a pin an output, while other peripherals override the TRIS bit to
make a pin an input. Since the TRIS bit override is in
effect while the peripheral is enabled, read-modifywrite instructions (BSF, BCF, XORWF) with TRISC as
destination, should be avoided. The user should refer
to the corresponding peripheral section for the correct
TRIS bit settings.
RD
TRIS
Peripheral
OE(3)
RD
Port
D
CK
Q
Q
P
1
D
CK
I/O
pin(1)
N
TRIS Latch
VSS
RD
TRIS
Schmitt
Trigger
Peripheral
OE(3)
Q
D
EN
RD
Port
CK
Q
Q
N
Vss
Schmitt
Trigger
Q
D
EN
0
Schmitt
Trigger
with
SMBus
levels
Note 1: I/O pins have diode protection to VDD and VSS.
2: Port/Peripheral select signal selects between port data
and peripheral output.
3: Peripheral OE (output enable) is only activated if
peripheral select is active.
Q
Q
D
1
Data Latch
WR
TRIS
I/O
pin(1)
CKE
SSPSTAT<6>
VDD
0
Q
P
1
SSPl Input
PORTC BLOCK DIAGRAM
(PERIPHERAL OUTPUT
OVERRIDE) RC<2:0>,
RC<7:5>
Peripheral Data Out
CK
VDD
Q
TRIS Latch
Port/Peripheral Select(2)
Data Bus
WR
Port
D
0
Data Latch
When the I2C module is enabled, the PORTC<4:3>
pins can be configured with normal I2C levels, or with
SMBus levels by using the CKE bit (SSPSTAT<6>).
FIGURE 3-5:
PORTC BLOCK DIAGRAM
(PERIPHERAL OUTPUT
OVERRIDE) RC<4:3>
Peripheral Input
Note 1: I/O pins have diode protection to VDD and VSS.
2: Port/Peripheral select signal selects between port
data and peripheral output.
3: Peripheral OE (output enable) is only activated if
peripheral select is active.
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PIC16F87X
TABLE 3-5:
PORTC FUNCTIONS
Name
Bit#
Buffer Type
Function
RC0/T1OSO/T1CKI
bit0
ST
Input/output port pin or Timer1 oscillator output/Timer1 clock input.
RC1/T1OSI/CCP2
bit1
ST
Input/output port pin or Timer1 oscillator input or Capture2 input/
Compare2 output/PWM2 output.
RC2/CCP1
bit2
ST
Input/output port pin or Capture1 input/Compare1 output/
PWM1 output.
RC3/SCK/SCL
bit3
ST
RC3 can also be the synchronous serial clock for both SPI
and I2C modes.
RC4/SDI/SDA
bit4
ST
RC4 can also be the SPI Data In (SPI mode) or data I/O (I2C mode).
RC5/SDO
bit5
ST
Input/output port pin or Synchronous Serial Port data output.
RC6/TX/CK
bit6
ST
Input/output port pin or USART Asynchronous Transmit or
Synchronous Clock.
RC7/RX/DT
bit7
ST
Input/output port pin or USART Asynchronous Receive or
Synchronous Data.
Legend: ST = Schmitt Trigger input
TABLE 3-6:
Address
SUMMARY OF REGISTERS ASSOCIATED WITH PORTC
Name
07h
PORTC
87h
TRISC
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on:
POR,
BOR
Value on all
other
RESETS
RC7
RC6
RC5
RC4
RC3
RC2
RC1
RC0
xxxx xxxx
uuuu uuuu
1111 1111
1111 1111
PORTC Data Direction Register
Legend: x = unknown, u = unchanged
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Web Site: www.parallax.com
Forums: forums.parallax.com
Sales: [email protected]
Technical: [email protected]
Office: (916) 624-8333
Fax: (916) 624-8003
Sales: (888) 512-1024
Tech Support: (888) 997-8267
Parallax Say It Module (#30080)
The Parallax Say It Modules provides voice recognition functions for built-in Speaker Independent (SI)
pre-programmed commands and up to 32 user-defined Speaker Dependent (SD) keywords (triggers,
commands, or passwords).
When you speak into this module, it will match the spoken word to a set of keywords that it has been
programmed to recognize. Once the module has determined if there is a match, it will take a defined
action, either listening for the next keyword in another “wordset” or executing the commands associated
with the word that was said. You can create up to 32 user-definable keywords.
The Say It GUI software for the BASIC Stamp 2 provides an easy interface for training the module and
producing template code. Or, the simple and robust serial protocol provided can be used to access the
Say It module functions from other Parallax microcontrollers. The 10-pin SIP header makes the module
breadboard friendly, and is designed to fit in one row of the AppMod header found on the Board of
Education and Boe-Bot Robot.
Features






23 Pre-programmed commands
Up to 32 user-definable commands
SIP for breadboard friendly projects (0.1” spacing)
GUI provides training and template code for BASIC Stamp 2
modules
On-board LED and microphone
Voice controlled Boe-Bot examples
Key Specifications




Power requirements: 3.3 to 5.5 VDC
Communication: Adjustable Asynchonous Serial (9600 (default),
19200, 38700, 57600, 115200)
Operating temperature: 32 to 158 °F (0 to 70 °C)
Dimensions: 1.02 x 2.47 x .38 in (26 x 62.93 x 9.70 mm)
Application Ideas



Voice-controlled entry systems
Automated house applications
Voice-activated robotics
Precaution

Do not solely rely on the Say It module to recognize a command for a safety stop if your project
requires one; take all appropriate precautions when implementing this module to maintain a safe
project.
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Using the Say It GUI Software
With the Say It GUI software for your PC and your BASIC Stamp 2 development board, you can test the
Say It module and train it to recognize your custom commands. During training, the BASIC Stamp 2
handles the Say It module-to-PC communication through the provided PBASIC “bridge” program. Once
your you have defined and tested your commands, the GUI software will generate a new PBASIC
template program ready for you to add the actions to take when your voice commands are received.
Follow the steps below to connect to the Say It module via the GUI software. This example assumes you
are using a Board of Education with BASIC Stamp 2, and you have previously installed the BASIC Stamp
Editor and tested the programming connection.
1. With the power to your board turned off (switch position 0) Plug the Say It module into the
AppMod header of the Board of Education (as seen in Figure 12); be careful to insert the module
in the left row of the header and in the correct orientation (Vss at top, Vdd at bottom, RX to P0,
TX to P2 and LED to P4).
Figure 1
2. Download and install the Say It GUI software from the 30080 product page at www.parallax.com.
Use the default installation path. For Windows Vista users, install as administrator.
3.
Start the Say It GUI software, and then connect the Board of Education to your PC and turn the
power switch on (position 1).
4. Select the serial port that the Board of Education/Say It module is connected from the toolbar
(Figure 1) or File from the menu, then Connect. See Figure 2.
BASIC Stamp Editor Debug Terminal must be closed before selecting “Connect” in
Say It GUI
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Serial port to use
Connect Icon
Figure 2
5.
Once connected, the Say It software prompts you to download the PBASIC “bridge” program to
the controller board, and switches to the programming mode (Figure 3). Choose Yes when
prompted.
Figure 3
A PBASIC “bridge” program will automatically be downloaded to the BASIC Stamp 2. This bridge program
allows the user to work with the set of SI commands the Say It module provides, as well as defining new
commands.
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6. Verify that the bridge download has been completed by the green status bar in the top right of
the GUI; it should remain full.
Once you have successfully connected to the module you can insert, add, remove, rename, train, erase,
test, reset all the commands, set the language used, or disconnect from the GUI. First, let’s cover testing
the pre-existing commands.
Testing Commands
Let’s begin by testing the words that are already programmed in the Say It module. These are grouped
under Trigger and three Wordsets (Figure 4).
Built-in Speaker Independent Commands
Trigger (0)
0
robot
Wordset 1
0
1
2
3
4
5
6
7
action
move
turn
run
look
attack
stop
hello
Wordset 2
0
1
2
3
4
5
left
right
up
down
forward
backward
Wordset 3
0
1
2
3
4
5
6
7
8
9
10
zero
one
two
three
four
five
six
seven
eight
nine
ten
Figure 4
1. Select a Trigger or Wordset to test by highlighting the option in the left window pane (Figure 5)
and then click “Test Group” from the tool bar. This example, I chose “Trigger” to test.
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Test Group
Figure 5
2. When the red LED indicator light on the module and the software window prompt you to speak,
speak clearly and directly at the microphone on the module. If the module understands, you will
see the command highlighted in green.
You can continue this with all the words that need to be tested. If the module does not understand the
word or there is nothing said, an information window will pop up indicating an error of a timeout. Later
you will want to use the same process to test any new commands that you train it to recognize.
Adding or Deleting Commands
When you want to create your own command, you can do so by using the Say It GUI. There are 4 types
of commands in the GUI:
•
•
•
•
Trigger – Trigger words are used to start the voice recognition process; all spoken command
phrases will begin with a trigger word. “Robot” is the SI trigger word, and you may train one
additional trigger word.
Group – Groups of user-definable SD commands. You may add up to 32 commands total (31 if
you also define a trigger word).
Password – A special group for “vocal passwords,” up to 5 may be defined.
Wordset – Built-in groups of Speaker Independent (SI) commands (Figure 3)
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The user can define groups of SD commands or passwords and generate a PBASIC code template to
handle them. The recognition function of Say It modules works on a single group at a time, so that users
need to group together all the commands that they want to be able to use at the same time.
When Say It GUI connects to the module, it reads back all the user-defined commands and groups, which
are stored into the Say It module’s non-volatile memory for later review and editing.
When training SI commands, simulate the environmental background noise in
which you want to use this module for the best results for recognition.
Adding a SD command can be completed by doing the following while the Say It “bridge” program is
running.
1. Select a group that you would like to add the word(s) to (Figure 6).
Figure 6
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2.
Click “Add Command” from the tool bar or menu (Figure 7), and provide a label. In this example,
the label “CREATE_LABEL_HERE” has been created; however it is suggested that you use a label
that you can later review and know what the word is.
Add
Command
Figure 7
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3. Select the label that in the right window pane, and click “Train” from the tool bar or menu
(Figure 8).
Train
Command
Figure 8
4.
Once you have selected Train Command; you will be prompted to say the phrase twice (figure 8)
to complete the training of a specific word; keep the words simplistic for optimal recognition. If
you are unhappy with the training, select erase training, and start the training process over from
step 3 until satisfied.
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Figure 9
5.
Once you have successfully created a phrase, you can test to confirm that it will recognize it, it is
suggested that you test each group after you are finished to ensure successful training. Once
finished you will see a number next to the group you trained; indicating how many words belong
to that group (Figure 9).
Figure 10
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If you want to remove a command, you can use the “remove command” from the tool bar or menu and it
will remove the selected command; once this is done it can not be undone so be sure you want to
remove a command prior to clicking this action.
Each of the Group, Password, and Trigger words are created and edited in the same manner that these
steps cover. Note: The Passwords (group 16) are much more sensitive to background environment noises
and distance from the microphone; but sure to train the password in conditions similar to where it will be
used.
Generating Code
Once you have created and trained all your desired commands, you can generate the PBASIC code to
then edit and assign actions to each of the words created. You can do that be completing the following:
1. Select the “Generate Code…” icon on the toolbar or from the menu (Figure 11)
Generate
Code
Figure 11
2. You will be prompted to save the file to then edit within the BASIC Stamp Editor (Figure 12).
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Figure 12
3. Click “Disconnect” in the GUI and open the file with the BASIC Stamp Editor.
4.
Once the program is opened in the BASIC Stamp Editor, there will be portions of the code that
will indicate where you will place the commands that will be used with the trained words. You will
see a PAUSE 1 with “'-- write your code here” comments.
5. Save your program, and then download to the BASIC Stamp 2 module and enjoy playing with
your new voice recognition module.
Sample Application for the Boe-Bot® Robot
Here is the sample applications that uses the Say It module to control a Boe-Bot robot with a BASIC
Stamp 2 on a Board of Education platform. The sample code for this application is available for download
on the Say It Module product page at www.parallax.com.
1. Plug the Say It module into the AppMod header of the Board of Education (as seen in Figure 1 on
page 2); be careful to insert the module in the left row of the header and in the correct
orientation (Vss at top, Vdd at bottom, RX to P0, TX to P2 and LED to P4).
2. Open the sample code labeled “SayIt_Demo.BS2” in the BASIC Stamp Editor.
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3. Install any batteries as needed, plug in the battery pack, and move the Board of Education power
switch to position 1
4. Download the program to the BASIC Stamp 2 module by clicking Run from the menu, and click
Run from the dropdown (ctrl + r)
5. Move the power switch to position 0, and unplug the communication cable; then move the power
switch to position 2.
6. Using the command list above (Figure 3); Say the trigger word (robot), and select then select a
word from Wordset 1, 2 and then 3 if needed. You can verify the word has been correctly
recognized by the red LED indicator on the Say It module.
When you say “robot”, the red LED will turn on for a short moment; once the LED is on, you can say the
next word. Once the Say It module has received the last Wordset command, it will execute the proper
routine associated with that command. Here are some samples that could be used and the descriptions of
the actions.
Try saying the following examples:
Robot -> Move -> Forward
Robot -> Hello
Robot -> Action -> Three
Robot -> Turn -> Right
Robot -> Run -> Backwards
Robot -> Stop
(-> = small pause)
(This will move the robot forward)
(Module will say hello on the debug screen, if one is open)
(Module will display 3 on debug screen, if one is open)
(This will turn the robot right)
(This will move the robot backwards)
(stops all movement)
After disconnecting from the Say It GUI, you can still verify that the Say It Module is detecting the right
word by using the Debug Terminal. By leaving the Board of Education connected to the computer, each
recognized verbal command will be printed to the Debug Terminal.
Note that not all commands will use a word from all 3 Wordsets to be a valid command. For example,
“Hello” uses a Trigger word (Robot) and Hello from Wordset 1, which will end the command to then
execute; that debugs “Hello” on the BASIC Stamp Debug Terminal.
Troubleshooting
From time to time there may be some snags that can cause what would seem like malfunctions in the
module. If you experience any of the symptoms listed below, here are some quick fixes to try.
Q1. Keep getting a time-out error
A1. Make sure the power has not been cycled since the last time the GUI was connected.
Q2. Can’t connect to my Say It Module
A2.1 Be sure to close all terminal windows including the debug screen before connecting the GUI
software.
A2.2 Check power and make sure it has ample voltage and current to turn on modules
Q3. Will not power up
A3. Check to make sure that all the connections are correct; if using an AppMod header be sure the
orientation is correct.
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Q4. I am running Windows Vista, and the Say It GUI will not install properly.
A4. Right Click on installer exe, and select “run as administrator”
Device Information
Specifications
Symbol
Quantity
Minimum
Typical
Maximum
Units
Vdd
Supply Voltage
3.3
5.0
5.5
V
Pin Definitions
Pin
Label
1
2
3
4
5
6
7
8
9
10
Vss
Rx
Tx
Led
Vdd
Function
Ground
Receive I/O Pin (TTL & CMOS compatible)
Transmit I/O Pin (TTL & CMOS compatible)
Red LED indicator
No Connection
No Connection
No Connection
No Connection
No Connection
5 V regulated DC
Connection Diagrams
This is the back view of the module, the connection pins are indicated on the silkscreen.
5 VDC (Pin 10)
no connect
no connect
no connect
no connect
no connect
x
x
x
x
x
Indicator LED
Transmit pin
Receive pin
Ground (Pin 1)
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Module Dimensions
63.22 mm
13.20 mm
26.21 mm
Communication Protocol
Communication with the Say It module uses a standard UART interface compatible with 3.3V to 5V TTL
logical levels. The initial configuration at power-on is 9600 baud, 8 bit data, No parity, 1 bit stop. The
baud rate can be changed later to operate in the range 9600 - 115200 baud.
The communication protocol only uses printable ASCII characters, which can be divided in two main
groups:
 Command and status characters, respectively on the TX and RX lines, chosen among lower-case
letters
 Command arguments or status details, again on the TX and RX lines, spanning the
range of capital letters
Each command sent on the TX line, with zero or more additional argument bytes, receives an answer on
the RX line in the form of a status byte followed by zero or more arguments.
There is a minimum delay before each byte sent out from the Say It module to the RX line, that is initially
set to 20 ms and can be selected later in the ranges 0 - 9 ms, 10 - 90 ms, 100 ms - 1 s.
The communication is host-driven and each byte of the reply to a command has to be acknowledged by
the host to receive additional status data, using the space character. The reply is aborted if any other
character is received and so there is no need to read all the bytes of a reply.
Invalid combinations of commands or arguments are signaled by a specific status byte, that the host
should be prepared to receive if the communication fails. Also a reasonable timeout should be used to
recover from unexpected failures.
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The module automatically goes to lowest power sleep mode after power on. To initiate communication,
send any character to wake-up the module.
Command Details
CMD_BREAK
“b”
Abort recognition in progress if any or do nothing
Expected replies: STS_SUCCESS, STS_INTERR
CMD_SLEEP
“s”
Go to the specified power-down mode
[1]
Sleep mode (0-8)
Expected replies: STS_SUCCESS
CMD_KNOB
“k”
Set Speaker Independent (pre-programmed commands) knob to specific level
[1]
Knob level (0-4)
Expected replies: STS_SUCCESS
CMD_LEVEL
“v”
Sets Speaker Dependent (custom programmed commands) to specific level
[1]
Threshold (1-5)
Expected replies: STS_SUCCESS
CMD_LANGUAGE
“l”
Set Speaker Independent (pre-programmed commands) language
[1]
Language ( 0 = English, 1 = Italian, 2 = Japanese, 3 = German
Expected replies: STS_SUCCESS
CMD_TIMEOUT
“o”
Set Speaker Independent (pre-programmed commands) language
[1]
Timeout (-1 = default, 0 = infinite, 1-30 = seconds
Expected replies: STS_SUCCESS
CMD_RECOG_SI
Activate Speaker Independent (pre-programmed commands) recognition from specified
“i”
wordset
[1]
Wordset Index (0-3)
Expected replies: STS_SUCCESS, STS_TIMEOUT, STS_ERROR
CMD_TRAIN_SD
Train specified Speaker Dependent (custom programmed commands) or Password
“t”
command
[1]
Group index (0 = trigger, 1-15 generic, 16 = password
[2]
Command position (0-31)
Expected replies: STS_SUCCESS, STS_RESULT, STS_SIMILAR, STS_TIMEOUT, STS_ERROR
CMD_GROUP_SD
“g”
Insert new Speaker Dependent (custom programmed commands) or Password command
[1]
Group index (0 = trigger, 1-15 generic, 16 = password
[2]
Command position (0-31)
Expected replies: STS_SUCCESS, STS_OUT_OF_MEM
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CMD_UNGROUP_SD
“u”
Remove Speaker Dependent (custom programmed commands) or Password command
[1]
Group index (0 = trigger, 1-15 generic, 16 = password
[2]
Command position (0-31)
Expected replies: STS_SUCCESS
CMD_RECOG_SD
“d”
Activate Speaker Dependent (custom command) or Password recognition
[1]
Group index (0 = trigger, 1-15 = generic, 16 = password
Expected replies: STS_SUCCESS, STS_RESULT, STS_SIMILAR, STS_TIMEOUT, STS_ERROR
CMD_ERASE_SD
“e”
Remove Speaker Dependent (custom command) or Password recognition
[1]
Command position (0-31)
Expected replies: STS_SUCCESS
CMD_NAME_SD
Give a label for a Speaker Dependent (custom programmed commands) or Password
“n”
command
[1]
Group index (0 = trigger, 1-15 = generic, 16 = password
[2]
Command position (0-31)
[3]
Length of label (0-31)
[4-n]
Text for label (ASCII characters from “A” to “`”
Expected replies: STS_SUCCESS
CMD_COUNT_SD
Request count of Speaker Dependent (custom programmed commands) or Password
“c”
commands in a specified group
[1]
Group index (0 = trigger, 1-15 = generic, 16 = password)
Expected replies: STS_COUNT
CMD_DUMP_SD
Read Speaker Dependent (custom programmed commands) or Password command label
“p”
(label and training)
[1]
Group index (0 = trigger, 1-15 = generic, 16 = password)
[2]
Command position (0-31)
Expected replies: STS_DATA
CMD_MASK_SD
“m”
Request a bit-mask of non-empty groups
Expected replies: STS_MASK
CMD_RESETALL
“r”
Reset all commands and groups
“R”
Confirmation character
Expected replies: STS_SUCCESS
CMD_ID
“x”
Request firmware ID
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Expected replies: STS_ID
CMD_DELAY
“y”
Set Transmit delay
[1]
Time (0-10 = 0 – 10ms, 11-19 = 20-100ms, 28-28 = 200 to 1000ms)
Expected replies: STS_SUCCESS
CMD_BAUDRATE
“a”
Set communication baud-rate
[1]
Speed mode (1 = 115200, 2 = 57600, 3 = 38400, 6 = 19200, 12 = 9600
Expected replies: STS_SUCCESS
Status Details
STS_MASK
“k”
Mask of non-empty groups
[1-8]
4-bit value that form a 32-bit mask, LSB first
In replay to: CMD_MASK_SD
STS_COUNT
“c”
Count of commands
[1]
Integer (0-31)
In replay to: CMD_COUNT_SD
STS_AWAKEN
“w”
Wake-up (back from power-down mode)
In replay to: Any character after power on or sleep mode
STS_DATA
“d”
Provide command data
[1]
Training information (0-7 = training count, +8 = SD/Password conflicts, +16 = SI conflict
[2]
Conflicting command position (0-31)
[3]
Length of label (0-31)
[4-n]
Text for label (ASCII characters from “A” to “`”
In replay to: CMD_DUMP_SD
STS_ERROR
“e”
Signal recognition error
Two 4-bit values that form 8-bit error code (80h = NOTA, otherwise see FluentChip error
[1-2]
codes)
In replay to: CMD_RECOG_SI, CMD_RECOG_SD, CMD_TRAIN_SD
STS_INVALID
“v”
Invalid command or argument
In replay to: Any invalid command or argument
STS_TIMEOUT
“t”
Timeout expired
In replay to: CMD_RECOG_SI, CMD_RECOG_SD, CMD_TRAIN_SD
STS_INTERR
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“i”
Interrupted recognition
In replay to: CMD_BREAK while in training or recognition
STS_SUCCESS
“o”
OK or no error status
In replay to: CMD_BREAK, CMD_DELAY, CMD_BAUDRATE, CMD_TIMEOUT, CMD_KNOB,
CMD_LEVEL, CMD_LANGUAGE, CMD_SLEEP, CMD_GROUP_SD, CMD_UNGROUP_SD,
CMD_ERASE, CMD_NAME_SD, CMD_RESETALL
STS_RESULT
Recognized Speaker Dependent (custom commands), Password or training similar to
“r”
Speaker Dependent (custom commands) and Password commands
[1]
Command position (0-31)
In replay to: CMD_RECOG_SD, CMD_TRAIN_SD
STS_SIMILAR
Recognized Speaker Independent (pre-programmed commands) work or training a similar
“s”
Speaker Independent (pre-programmed commands) command
[1]
Wordset indext (0-31)
In replay to: CMD_RECOG_SD, CMD_TRAIN_SD,CMD_RECOG_SI
STS_OUT_OF_MEM
“m”
Memory Full Error
In replay to: CMD_GROUP_SD
STS_ID
“x”
Provide firmware ID
[1]
Version ID (0)
In replay to: CMD_ID
Argument Mapping
ARG_MIN
“@”
Minimum argument value (-1)
ARG_MAX
“‘“
Maximum argument value (-1)
ARG_ZERO
“A”
Zero argument value
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