I am currently programming the arduino mega to send signals to control three Sabertooth 2x12 motor controller. Each controller is capable of running two motors with PWM power control. The motor controller can accept three types of signals: Analog (Must be used with low pass filter with Arduino to filter out the PWM), Servo/RC style control, and Serial The question I am asking is that which one of these is the most efficient (meaning that it takes the least time to process and send the signals/data) and least CPU consuming (uses up the least CPU time).
All three types of signals will need an individual signal for each motor, meaning that for analog, 6 PWM pins will be used, and same goes for the Servo/RC style control. As for serial, each motor signal consists of four lines of single byte data using serial.write() for each line. This however will only take up one pin (serial tx) on the arduino.
Please ask if you have any questions concerning my setup. I can explain it in more detail.