axe027 picaxe usb cable

axe027 picaxe usb cable
AXE027 PICAXE USB CABLE
1) Introduction
The PICAXE USB download cable is used to download PICAXE
programs into PICAXE chips. It can be used with any PICAXE chip
or project board. The cable is compatible with any software
application that supports programming of PICAXE chips.
The PICAXE USB download cable connects via the computer’s USB
port. However the cable contains a tiny circuit board, moulded into
the compact USB connector. This circuit contains a USB to serial
convertor chip, and so the actual data transfer to the PICAXE chip is
via a 5V logic level serial connection.
When the AXE027 software driver is installed, the operating system
automatically allocates the USB cable a ‘COM port number’ to be used
within the PICAXE Programming Editor software. If you are not sure which COM
port number has been allocated, click the View>Options menu, select the ‘Serial
Port’ tab and then click the ‘Setup’ button. The Device Manager will then start click the ‘+’ symbol beside ‘Ports (COM & LPT)’ so that all the entries are visible.
Beside the ‘AXE027 PICAXE USB’ entry will be the currently allocated COM port
number. Section 4 of this manual explains how to change this COM port number
if necessary.
2) Tips for using the AXE027 USB cable
Always plug in the USB cable before starting the Programming Editor software.
Always use the USB cable in the same USB port on your computer. The Windows
operating system regards each individual USB port as a unique location.
Therefore if you plug your cable into a different USB port you may be prompted
by Windows to reinstall the driver files for this new location.
The USB cable’s internal circuit board is powered by the computer’s USB port.
Therefore remove the cable from the PICAXE project when the USB end of the
cable is not inserted into a computer, as the cable will not then be powered.
3) Installing the AXE027 PICAXE USB Cable Driver
The first time you connect the AXE027 PICAXE USB cable you will be
automatically prompted to install the software driver files. These driver files can
be found on the Programming Editor CDROM (in the USB_drivers_AXE027
folder) or downloaded free of charge from the software downloads section at the
main PICAXE website (www.picaxe.co.uk).
Please ensure you are using the correct driver package for your operating system.
The available Windows driver options are:
- Windows XP, XP (64 bit edition), 2003, 2000, ME, 98SE
There is no operating system support for USB within Windows 95 or NT. For these two old
operating systems you must use the AXE026 serial cable instead.
If using the downloaded driver files from the website, unzip the downloaded
files into a temporary folder (e.g. c:\temp) before proceeding.
On computers setup with user accounts (e.g. school networks) please ensure you
are logged in as an administrator before proceeding.
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Revolution Education Ltd. Email: info@rev-ed.co.uk Web: www.picaxe.co.uk v1.0 06/06/06
SRF005.PMD
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PICAXE USB CABLE
Step 1
Plug the AXE027 USB cable into an available USB port on
your computer. Remember which port you have used as it
is important to always use the same port in the future (to
avoid having to reinstall the software drivers).
After a few seconds Windows will recognise that the cable
has been inserted and will automatically prompt you with
the ‘Found New Hardware Wizard’.
Step 2
If this is the first time the cable has been used, select
‘Install from a list or specified location (Advanced)’ and
then click ‘Next’
If you have previously already installed the drivers onto the
computer, you can select ‘Install the software automatically’
instead, as the drivers will be ready to use.
Step 3
Select ‘Search for the best driver in these locations’ and
browse to the drivers folder. This is either the appropriate
folder within the ‘USB_drivers_AXE027’ folder on the
Programming Editor CDROM or the temporary folder on
your hard-drive where the website downloaded driver files
have been saved (e.g. c:\temp).
Click ‘Next’
Step 4
If a Windows logo testing warning is displayed click
‘Continue Anyway’
Note that the generic FTDI software drivers to be installed during
this process have already passed Windows logo testing. However
due to legal reasons when distributed by a third party (e.g.
Revolution) they cannot currently be marked as passed.
Step 5
Click ‘Finish’ when the installation completes.
Step 6
Please note the entire process (steps 2 to 5) will now
repeat. This is completely normal as the Windows
operating system requires two separate driver files for the
AXE027 cable to operate.
The Windows operating system will now automatically allocate the
AXE027 USB cable a default ‘COM port number’ to use within the
Programming Editor software. However this automatically
allocated COM port number may not be suitable (e.g. COM20)
and may need to be re-assigning to another port (e.g. COM4).
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AXE027.PMD
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PICAXE USB CABLE
4) Changing the default ‘COM Port Number’
After initial driver installation, the Windows operating
system will automatically allocate the AXE027 USB cable a
default ‘COM port number’ to use within the Programming
Editor software. However this automatically allocated port
number may not be suitable (e.g. COM20) and may need reassigning to another COM port number (e.g. COM4).
Step 1
Start the Programming Editor software.
Select the View>Options menu and click on the ‘Serial Port’
tab. Note which ports are greyed out (not used).
Select one of these greyed out port numbers (e.g. in this
example COM4)
Click the ‘Setup’ button to launch Device Manager.
Step 2
Click on the ‘+’ beside ‘Ports (COM and LPT)’ to browse the
current ports. Select the ‘AXE027 PICAXE USB’ entry and right
click the mouse. Select ‘Properties’.
Step 3
Select the ‘Port Settings’ tab and then click the ‘Advanced…’
button
Step 4
The COM Port number currently allocated is shown on screen
(COM20 in this example).
From the COM port number list select the desired new COM
port number and then click ‘OK’ twice to save the new port
number (none of the other settings need to be changed).
Note that sometimes the Windows operating system marks ports as
‘in use’, even though they are not actually in use at that time. This is
because Windows is ‘reserving’ the COM port number for a
particular device. This can occur, for instance, if you plug your
AXE027 cable into a different USB port on the computer - Windows
is expecting the cable to be inserted into the original USB port and so
is reserving the COM number for that USB port. You may change to
COM ports marked as ‘in use’ but will have to OK the extra
Windows warning message.
Step 5
In the Programming Editor now click the ‘Refresh’ button.
The desired COM port should now become available. Select
this port and then click ‘OK’. The system is now ready for use.
This process is only required once as Windows automatically saves
the COM port settings for this cable for future use (when used in this
USB port location).
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(c) Revolution Education Ltd. Email: info@rev-ed.co.uk Web: www.picaxe.co.uk V1.0 06/06/06
AXE027.PMD
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PICAXE USB CABLE
5) PICAXE Download Circuit
serial out
serial in
0V
Above view
22k
x
x
x
x
10k
x
PICAXE
The standard PICAXE download socket (part CON039) and 10k/22k download circuit
is unchanged for use with the AXE027 USB cable (ie the same circuit is used for both
the AXE026 serial cable and the AXE027 USB cable).
As the AXE027 interfacing voltage is at true logic levels (5V, rather than RS232
voltage levels) it is theoretically permissible to reduce the value of the 22k resistor
(e.g. to 1k), but only if a AXE026 serial cable is never to be used. However for
maximum versatility it is recommended to leave the circuit unchanged.
There is no advantage to using the ‘enhanced’ download circuit (see main PICAXE
manual) with the AXE027 USB cable, as the enhancements in this circuit are to
compensate for negative variations in RS232 voltages (which do not apply when
using the 5V logic level AXE027 USB cable). However, if already built into a project
board, it is acceptable to continue to use the enhanced circuit.
The AXE027 USB cable may also be used to transmit/receive serial data from the
PICAXE input/output pins (via serin and serout commands).
6) AXE027 Circuit Diagram
The miniature USB to serial circuit is built into the plastic moulding of the USB plug
on the AXE027 cable. The circuit diagram is shown below.
AXE027
PICAXE
USB Cable
(c) 2006
FB
4.7u
100n
+
1
FT232RQ
USB ‘A’
15
14
10n
revolution
47p
47p
18 19
16
100n
100
30
3.5mm
TXD
2
RXD
32
8
4 17 20 24 26
100
OV
2x
10k
(c) Revolution Education Ltd. Email: info@rev-ed.co.uk Web: www.picaxe.co.uk V1.0 06/06/06
AXE027.PMD
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