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Set up MP Lab on Your Own Computer. This project is largely software-based, and lab stations will quickly become prime real-estate. Tooling up with a free version of the PIC development environment and some free compilers helped our team develop more quickly. LED's are Great for Debugging. Even when printf() is available on your microcontroller, toggling an LED can provide valuable insight. Heartbeat and status LED's are simple ways to better understand a live system and immediately know when a something has gone awry and quickly lead you to the problem. And of course, the more granular you make your indicators, the better. Plug n' Program. A dedicated Molex for re-programming each PIC is a great way to develop quickly. Found a mistake? Just plug in your PICkit3 and program and you're back off to the races. Great New Tool: The Bus Pirate. A must-have for communication development. This offers a great way to check whether the signal was ever transmitted or was ever received, really helping you isolate at what point and on what side of the transmission a signal was lost. Bug Alert: Use a Series Resistor when Probing the XBee Tx and Rx lines with a Series Resistor. The oscilloscope and the bus pirate, while designed to probe with negigible affect on the signal with high-impedance lines, introduce incredible noise on the XBee Tx and Rx lines. An approximately 1k resistor placed in series between the XBee line and the oscilloscope or bus pirate seemed to provide enough impedance to be able to accurately sense the signal. (still remains a mystery) Bug Alert: The PIC's Stack is Only 8 Levels Deep. So watch how complex you make your program. In particular, avoid making use of recursion (it's really not necessary in these state machines anyways). |
