I programmed an AtMega8 with arduino libraries using cmake to control a nokia display.
The AtMega8 is configured as an i2c slave to receive the instructions from an embedded linux box.
I tested it with a raspberrypi and it worked well.
Now I wanted to assemble it with a bifferboard, and it refuses to communicate. The device is not even listed with i2cdetect.
With the scope I found out that the raspberry pi's SCL runs at 100khz, which I read is the standard speed also for Arduino.
But the SCL of the bifferboard runs at only 32.5 khz. The BlinkM has no problem with that, but my AtMega8 does.
Now how could I make my AVR work as an i2c slave at 32.5 khz?
The full code is at : https://github.com/ulrichard/rfidtime/tree/master/nokia_display_i2c
I don't know it that's relevant, but the AtMega8 runs at 8Mhz, using an external resonator .While I think the old Arduino that used an AtMega8 was at 16Mhz. I set the frequency at the beginning of the cmake file. So, most timings work correctly, but I noticed that the tone() function is still off.