CMUCam over programming port problems..

Here’s my current configuration - I have the CMUCam2 connected to the programming port with a M/M Serial Cable. Over the TTL connection it works perfectly, however, over the programming port, it doesn’t. The servos center, the lights are on, both of them, on the CMUCam2. This is normally indicative of no camera signal.

I connected the programming port to my laptop, and ran a terminal program. I repeatedly received the CR?>, which I assume to mean camera ready? message. I am not receiving anything else, such as printf debug messages; so that can not be the cause of failure. I have tested the camera over the serial port with the java application, it also works fine.

I’m out of places to look, I reset the robot controller multiple times, and the voltage on the backup battery was 8.2 volts. I went through the FAQ already.

Did you change the serial port the camera code is using?

Is the terminal serial port the same as the camera?

Yes - I changed the code. I am getting the CR?> message over the programming port.

The camera is plugged into the programming port. I unplugged it, and hooked my laptop to the port to use as a terminal.

If you want, zip-up your code and send it to me and I’ll have a quick look this evening.


I had a look at your code and didn’t see anything obvious related to the camera. My guess is that you’re using a straight through serial cable when a null-modem cable is needed. If you can, reverse pins 2 and 3. Also, in your timer ISR, make sure that you also check the timer interrupt enable too. It should look something like this:

else if (PIR1bits.TMR1IF && PIE1bits.TMR1IE)

Let me know if it’s not the cable.


That fixed it - thanks.