Maxim USBTO232 User guide

Maxim USBTO232 User guide
19-1738; Rev 1; 5/07
MAX1284 Evaluation Kit/Evaluation System
The MAX1284 evaluation system (EV system) is a complete data-acquisition system consisting of a MAX1284
evaluation kit (EV kit), Maxim 68HC16MODULE-DIP
microcontroller (µC) module, and USBT0232. The
MAX1284 is a high-speed, 12-bit data acquisition system.
Windows® 98/2000/XP-compatible software provides a
handy user interface to exercise the MAX1284’s features.
Order the complete EV system (MAX1284EVC16) for
comprehensive evaluation of the MAX1284 using a PC.
You can order the EV kit (MAX1284EVKIT) if the
68HC16MODULE-DIP module has already been purchased with a previous Maxim EV system, or for custom
use in other µC-based systems.
Features
o
o
o
o
o
Proven PCB Layout
Convenient On-Board Test Points
Data-Logging Software
Fully Assembled and Tested
EV Kit Software Supports Windows 98/2000/XP
with RS-232/COM Port
o EV Kit Software Supports Windows 2000/XP with
USB Port
Ordering Information
PART
Windows is a registered trademark of Microsoft Corp.
Component Lists
MAX1284 EV System
PART
QTY
1
MAX1284 EV kit
68HC16MODULE-DIP
1
68HC16 µC module
USB-to-COM port
adapter board
+Denotes lead-free and RoHS-compliant.
USBT0232+
1
MAX1284 EV Kit
DESIGNATION
QTY
C1
1
0.01µF ceramic capacitor
DESCRIPTION
C2, C3
2
0.1µF ceramic capacitors
C4
1
4.7µF tantalum capacitor
C5
1
10µF, 10V tantalum capacitor
J1
1
2x20 right-angle socket
JU1
1
2-pin header
JU2
1
3-pin header
R1
1
1kΩ ±5% resistor
TP1
1
6-pin header
U1
1
MAX1284BCSA (8-pin SO)
—
1
PCB: MAX1284 Evaluation Kit
MAX1284 EV Kit Files
FILE
DESCRIPTION
INSTALL.EXE
Installs the EV kit files on your computer
MAX1284.EXE
Application program
KIT1284.C16
Software loaded into 68HC16 µC
INTERFACE TYPE
MAX1284EVKIT
0°C to +70°C
User supplied
MAX1284EVC16
0°C to +70°C
Windows software
Note: The MAX1284 software is designed for use with the complete MAX1284EVC16 EV system (includes 68HC16MODULE-DIP
module, USBT0232, together with MAX1284EVKIT). If the
MAX1284 evaluation software will not be used, the
MAX1284EVKIT board can be purchased by itself, without the µC.
DESCRIPTION
MAX1284EVKIT
TEMP. RANGE
Quick Start
Recommended Equipment
(USB Port/PC Connection Option)
Before beginning, the following equipment is needed:
• MAX1284 EV system:
MAX1284 EV kit
68HC16MODULE-DIP
USBTO232 (USB cable included)
•
A small DC power supply, such as a 12VDC, 0.25A
plug-in transformer or a 9V battery
•
A user-supplied Windows 2000/XP computer with
an available USB port to connect to the USBTO232
board
Note: In the following sections, software-related items
are identified by bolding. Text in bold refers to items
directly from the EV kit software. Text in bold and
underlined refers to items from the Windows 2000/XP
operating system.
Connections and Setup
The MAX1284 EV kit is fully assembled and tested.
Follow the steps below to verify board operation.
Caution: Do not turn on the power until all connections are completed.
1) Visit the Maxim website (www.maxim-ic.com) to
download the latest version of the USBTO232 User
Guide. Follow the steps in the USBTO232 User
Guide Quick Start section and return to step 2 of
this Quick Start section when finished.
________________________________________________________________ Maxim Integrated Products
1
For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
Evaluate: MAX1284
General Description
Evaluate: MAX1284
MAX1284 Evaluation Kit/Evaluation System
2) Carefully connect the boards by aligning the 40-pin
header of the MAX1284 EV kit with the 40-pin connector of the 68HC16MODULE-DIP module, both
boards component side up. Gently press them
together. The two boards should be flush against
one another.
3) Ensure that jumper JU1 is open and jumper JU2 is
in the 1-2 position.
4) Connect a +7VDC to +20VDC power source to the
µC module at the terminal block located next to the
on/off switch, along the top-edge of the µC module.
Observe the polarity marked on the board.
5) Connect the USBTO232 board to the
68HC16MODULE-DIP module if you have not done
so already.
6) The MAX1284 EV kit software should have already
been downloaded and installed in the USBTO232
Quick Start.
7) Start the MAX1284 program by opening its icon in
the Start | Programs menu.
8) Turn on the power supply and slide SW1 to the ON
position on the 68HC16MODULE-DIP module.
Press the OK button to automatically connect and
download the file KIT1284.C16 to the module.
9) Apply an input signal between AIN and GND.
Observe the readout on the screen.
Recommended Equipment
(RS-232-to-COM Port/PC Connection Option)
Before beginning, the following equipment is needed:
• MAX1284 EV system:
MAX1284 EV kit
68HC16MODULE-DIP
•
•
•
A small DC power supply, such as a 12VDC, 0.25A
plug-in transformer or a 9V battery
A user-supplied Windows 98/2000/XP computer
with an available serial communications port,
preferably a 9-pin plug
A serial cable to connect the computer’s serial port
to the 68HC16MODULE-DIP
Connections and Setup
The MAX1284 EV kit is fully assembled and tested.
Follow the steps below to verify board operation.
Caution: Do not turn on the power until all connections are completed.
1) Visit the Maxim website (www.maxim-ic.com/evkitsoftware) to download the latest version of the EV
kit software. Save the EV kit software to a temporary
folder and uncompress the file (if it is a .zip file).
2) Install the MAX1284 EV kit software on your computer by running the INSTALL.EXE program. The
program files are copied and icons are created for
them in the Windows Start | Programs menu.
3) Carefully connect the boards by aligning the 40-pin
header of the MAX1284 EV kit with the 40-pin connector of the 68HC16MODULE-DIP module, both
boards component side up. Gently press them
together. The two boards should be flush against
one another.
4) Ensure that jumper JU1 is open and jumper JU2 is
in the 1-2 position.
5) Connect a +7VDC to +20VDC power source to the
µC module at the terminal block located next to the
on/off switch, along the top-edge of the µC module.
Observe the polarity marked on the board.
6) Connect a cable from the computer’s serial port to
the µC module. If using a 9-pin serial port, use a
straight-through, 9-pin female-to-male cable. If the
only available serial port uses a 25-pin connector, a
standard 25-pin-to-9-pin adapter will be required.
The EV kit software checks the modem status lines
(CTS, DSR, and DCD) to confirm that the correct
port has been selected.
7) Start the MAX1284 program by opening its icon in
the Start | Programs menu.
8) Turn on the power supply and slide SW1 to the ON
position. Select the correct serial port and press
OK. The program will automatically download
KIT1284.C16 to the module.
9) Apply an input signal between AIN and GND.
Observe the readout on the screen.
Table 1. Jumper JU1 Functions
JUMPER
JU1
POSITION
Closed
SHDN driven by µC; JU2 must be
open
1-2*
SHDN set by JU2
Operate
2-3
Shutdown
Open*
JU2
FUNCTION
*Default position.
2
_______________________________________________________________________________________
MAX1284 Evaluation Kit/Evaluation System
Evaluate: MAX1284
GND
J1-1
GND
J1-2
J1-3
3 JU2
J1-4
J1-7
C5
10µF
1
2
VDD
VDD
J1-8
J1-28
J1-30
C2
0.1µF
SCLK
JU1
UPSHDN
SHDN
3
6
J1-33
J1-34
J1-35
CS
8
DOUT
7
DOUT
J1-37
SCLK
J1-38
CS
SHDN
VDD
DOUT
U1
AIN
SCLK
MAX1284
REF
CS
GND
1
R1
1k
2
4
GND
TP1-2
VDD
TP1-3
SCLK
TP1-4
CS
TP1-5
DOUT
TP1-6
SHDN
J1-25
J1-26
J1-27
J1-29
J1-31
J1-32
J1-36
J1-19
J1-20
J1-21
J1-22
J1-23
J1-24
AIN
C4
4.7µF
VREF
(2.5V NOMINAL)
5
C3
0.1µF
TP1-1
C1
0.01µF
J1-40
J1-13
J1-14
J1-15
J1-16
J1-17
J1-18
J1-39
J1-5
J1-6
J1-9
J1-10
J1-11
J1-12
Figure 1. MAX1284 EV Kit Schematic Diagram
Detailed Description
Description of Software
MAX1284 Stand-Alone EV Kit
The evaluation software’s main window controls the
serial-clock speed and sample rate. It displays the voltage and output code as well as some statistics of the
input signal. A separate graph window shows the data
changing in real time. The update rate is limited to
about 10 samples per second, due to COM port bandwidth limitations.
The MAX1284 EV kit provides a proven PCB layout to
evaluate the MAX1284. It must be interfaced to appropriate timing signals for proper operation. Connect +5V to
VDD, and connect the ground return to GND (Figure 1).
Refer to the MAX1284 data sheet for timing requirements.
MAX1284 EV System
The MAX1284 EV system operates from a user-supplied +7VDC to +20VDC power supply. Windows
98/2000/XP-compatible software running on a PC interfaces to the EV system board through the computer’s
serial communications port. See the Quick Start section
for setup and operating instructions.
Statistics
The Minimum and Maximum fields show the highest
and lowest readings acquired. The Average field shows
a running mean based on the equation ai = (k)(xi) +
(1 - k)(ai - 1). The Clear button resets the statistics. To
remove offset errors, first apply 0V to the active input
channel, clear statistics, acquire some samples, and then
check Tare. This average offset voltage will now be subtracted from all subsequent measurements.
_______________________________________________________________________________________
3
Evaluate: MAX1284
MAX1284 Evaluation Kit/Evaluation System
Sampling
Choose the desired sampling rate (QSPI™ Clock),
sampling size (Sample! menu item), and press Begin
Sampling! (in Sample! pop-up window). Sample size is
restricted to a power of 2 to permit FFT processing
once the data is saved to a file. After the samples have
been collected, the data is automatically uploaded to
the host and graphed. Once displayed, the data can
be saved optionally to a file.
Saving Graphs to Disk
Data in the real-time graph and in sampled data graphs
may be saved to a file. Only the raw output codes are
saved, but voltages may be inferred, based on the reference voltage and the maximum code value.
Evaluating Shutdown
The evaluation software configures the 68HC16’s QSPI
submodule to continuously read data from the
MAX1284 into the 68HC16. The sample rate is controlled by the QSPI clock. To evaluate power-saving
modes, these automatic updates must be stopped.
First, set the QSPI clock control to STOP. This reconfigures the 68HC16’s QSPI submodule to stop driving the
serial clock. Second, in the evaluation software’s main
window, uncheck the Read Every...msec checkbox. If
evaluating the hardware shutdown, move jumper JU2
to the 2-3 position.
Reference Voltage
The evaluation software assumes a 2.5V reference voltage, unless otherwise specified. Refer to the MAX1284
data sheet for more information. To override this value,
type the new reference voltage into the Vref edit box
and press the Set Vref button.
Detailed Hardware Description
The MAX1284 (U1) is a high-speed, 12-bit dataacquisition system. Resistor R1 (1kΩ) and capacitor C1
(0.01µF) form a single-pole, low-pass anti-aliasing filter
with a nominal 10µs time constant and a corner frequency of approximately 16kHz. C3 and C4 bypass the
analog-to-digital converter’s (ADC’s) voltage reference.
When plugged into the 68HC16MODULE, the VDD circuit is powered by +5V (Figure 1; refer to the MAX1284
IC data sheet).
Troubleshooting
Problem: No output measurement. System seems to
report zero voltage or fails to make a measurement.
1) Check the VDD supply voltage.
2) Check the reference voltage using a DVM.
3) Use an oscilloscope to verify that the conversionstart signal is being strobed. Verify that SHDN is
being driven high.
Problem: Measurements are erratic, unstable; poor
accuracy.
1) Check the reference voltage using a DVM.
2) Use an oscilloscope to check for noise.
3) When probing for noise, keep the oscilloscope
ground return lead as short as possible, preferably
less than 1/2in (10mm).
QSPI is a trademark of Motorola, Inc.
4
_______________________________________________________________________________________
MAX1284 Evaluation Kit/Evaluation System
Evaluate: MAX1284
1.0"
Figure 2. MAX1284 EV Kit Component Placement Guide—
Component Side
1.0"
Figure 3. MAX1284 EV Kit PCB Layout—Component Side
_______________________________________________________________________________________
5
Evaluate: MAX1284
MAX1284 Evaluation Kit/Evaluation System
1.0"
Figure 4. MAX1284 EV Kit PCB Layout—Solder Side
Revision History
Pages changed at Rev 1: Title change—all pages, 1–6
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
6 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2007 Maxim Integrated Products
is a registered trademark of Maxim Integrated Products, Inc.
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