Adding gcc command line defines

Projects Programming
1

I need to change the TWI_FREQ on a per project basis and hoped to be able to just add -DTWI_FREQ=400000 to the gcc command line used by a project but I can find no way of doing this thought the Arduino IDE. What am I missing?

2

Use Wire.setClock(). The default is : Wire.setClock(100000UL);
I don't know what the maximum or minimal values are, but 200kHz and 400kHz do work.

It is possible to add compiler options to platform.local.txt

3

Thanks Peter.