We need to design an integrated DC motor controller/driver, which will be under microprocessor control. Due to space requirements, either the digital and analog circuitry will be on a single PCB (think of PC104 size), or they will be stacked on top of each other (again, similar to how pc104 boards are stacked). The load requirements are about 10A at 30V. Stall current can go up to 25A.
In order to protect the controller from the motor, we want to isolate the control signals. In fact, even the power supply and the grounds for the digital and analog sides are different. (Note that this means the the ground of the analog side can be at an entirely different voltage than the ground of the digital side)
My questions are: What is a good way to isolate these two domains (optocouplers, maybe?). The signaling rate between the two domains need to be around 1Mhz.
Also, I'm a bit worried about the noise from the motor affecting the digital circuitry, even with proper isolation of the control signal lines. Just being physically close to a motor sometimes even causes problems, let alone being physically connected. I would like to hear about your experiences in building motor controllers/drives to we don't make the same mistakes.