[adamdb]

Alan,
I did sort of say we weren't using the I component by saying we were using P&D, but should have been a little more clear. I took a pass through the comments, but as usual missed a few that no longer matched up with the code. Odd that you have had issues with 255, we have always used it without issues.

Don,
The drive setup is a typical setup with one motor on each side (facing opposite directions) that power the drive wheels on that side. As the motors face opposite directions we need to do the inversion for (in our case) the right side as shown in the bottom of the PID_adjust() routine.

// Invert the right output and put them to the wheels
OUT_PWM_LM = left_out;
OUT_PWM_RM = 255 - right_out;

I definitely urge you to play with the gyro and this code and the other available examples for driving the robot. We hadn't used a gyro in previous years because I didn't understand them or PID routines, but dug into it this year and did some reading and the result has been great.

Render,
As I mentioned in the original post the code was not optimized for size or speed and we will get rid of the floats in future revisions. The errors were made floats so it didn't have to add code to convert from an integer to floating point before it made the calculations.

Thanks all for the feedback!
Adam