I'm interested in using raspberry to control a number of brushless motors. PWM should be executed parallely to work in needed rate. As far as I've heard, RPi provides only consequent requests to GPIO's. The obvious solution here is to use I2C or SPI as a working protocol between RPi and PIC. PIC itself would translate PWM to motors simultaneously. The question is if it's any common way of doing it? Like an add-on chip that I can put on RPi to make outputs parallel?