Friday, November 27, 2009

After our last unsuccessful try to communicate with the Vectra CANBUS, we decide to take a step backward and ensure that we were doing things the right way. In particular, we were interested in knowing if the CANBUS chip was connected right and if the logic of the program was correct.
To test this we got another breadboard and tried to replicate our current circuit so that we would eventually have two CANBUS connected PICs that could talk together, confirming we were doing things right.
So this was the breadboard at the actual state of the project:
And this one is the new breadboard with the essential part of the circuit cloned:
We went on and attached the programmer to the new breadboard but it did not work. The programmer simply could not find the PIC. We feared we had burned some chip due to incorrect power connections and proceeded checking differences with the original circuit. There weren't any.
To check whether we had really burnt the chip, we put it in the original breadboard and worked as expected. After putting it back in the new breadboard we could not figure what was wrong and spent really a lot of time trying to iron this out. In the end, we removed every chip and connection from the board and put them back in a different position paying extra attention to any connection. This time the chip worked and could be finally programmed and run.
We proceeded to connect the boards and wrote a different program on each chip, one that transmitted one message and the other that printed to the serial port the messages received (only the original breadboard has serial port chips). It didn't work. We tried to change the programs but it was already too late and we had to stop there.
Next time we hope to have the two boards communicate via CANBUS.

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