Light Buddy Firmware (part 4)

Achieved all of the basic functionality, internal EEPROM, timers, USB, and the support structure.  Tested all the features and they look good.  What I like to do on each one of these is test the timer routines to make sure all the arithmetic was correct.  You would think after about 30 of these PIC implementation, I would have this down, but I continue to surprise myself with stupid mistakes.

Here are three scope shots that show the pulse width for the 1ms, 10ms and 25ms timer settings.  I use the timers in both a blocking function and as an interrupt driven timer.  The PIC18F25K50 has two 16 bit timers that I use for this.  The two 8 bit timers will be used for the PWM engines.

Here are the scope pictures.

1 ms

10 ms

25 ms

The timing was not too bad.  If the scope's calculation on frequency is correct then the actual timing was

1ms    => 1.005555ms  or 0.5555% error
10ms  => 10.01645ms  or 0,1645% error
25ms => 25.05286ms  or 0,21145% error

This is good enough for timing the light s on a MOC.

Next is to install the LP5569 LED controllers and get the I2C bus working.  Never used these before so it should be interesting.  Plus these are very small parts, so installing is going to be fun.