Actuator Core: implement PWM and SPI

[wocsor]

Currently, Actuator controls the motor drivers with binary states. This works for actuator types with high hysteresis and position control, but for steering control this won't work. Implementing PWM to handle the motor drivers will be a better solution long-term.

Additionally, the motor drivers have SPI connected to gather the driver state, such as current draw and error states. This info is useful for sending diagnostic information about the board to the user.

• implement PWM on GPIO connected to motor driver PWM pins
• read in PWM set value from CAN, positive and negative set the DIR pin on the driver and absolute value is sent on to the driver
• setup SPI peripheral connected to driver
• send SPI messages to driver
• read SPI messages from driver
• output driver states to CAN

[wocsor]

PWM implemented in eee8028
SPI is able to bring up per the scope but driver chips don't seem to respond. need to look into that more.