For those that might be interested, I've created a utility application that can be used to verify the proper operation of your robot controller's serial ports, CMUcam2, TTL to RS232 conversion circuit, and cables. The code can be found here:
http://kevin.org/frc. Here's the readme file:
Code:
FRC robot controller serial port diagnostics is a utility to
test the serial ports of your robot controller. It simply
takes all data sent to the programming port and sends it back
out the TTL-level serial port and conversely takes all data
sent to the TTL-level serial port and sends it back out the
programming port. Two important tests can be performed with
this software:
1) First is a loop-back test, which tests the the transmit
and receive circuits of both serial ports at the same time.
To perform this test, attach the programming cable between
your computer and robot controller and using the IFI loader,
upload the serial_port_diagnostics.hex file included with
this project. Once you've done that and see the text "Serial
Port Diagnostics Running..." on your terminal window, remove
power from your robot controller and install the IFI TTL to
RS232 interface board and PWM cable that came with your
CMUcam2. Now short the red and white pins together with a
small piece of wire or a 0.1" jumper block. Now apply power
to your robot controller and once the "Serial Port Diagnostics
Running..." text appears, type some characters into the "To
Port ->" box under the terminal window and press the enter
key. Did the same characters appear on your terminal window?
If not, make sure everything is connected properly and try the
test again. If the correct characters did appear, you know that
your serial ports, TTL to RS232 board and cable are working.
2) The second test involves plugging the PWM cable back into
your CMUcam2 and applying power to the robot controller and
CMUcam2. Once the "Serial Port Diagnostics Running..." text
appears, Click within the "To Port ->" window and press the
enter key a few times. Did the text "ACK" or "NCK" appear on
your terminal window? If not, it means that your camera is
either misconfigured (e.g., wrong baud rate) or defective.
If you got at least one "ACK" back from the camera, you know
that you can successfully communicate with your CMUcam2.
-Kevin