3.a.05. Command 144: Joint Motor Operation (inA1 = inB1 = in1; inA2 = inB2 = in2)

Effect: Use dual motor drivers together as a single, more powerful motor driver. The settings of in1 and in2 determine if the effect is brake low, forward, or reverse at thedesired PWM. This command sets motor to the specified state immediately. It is not possible to brake high in joint motor mode. It is also not possible to take advantage of current-sensing while in joint motor mode. Joint motor control works by PWMing the low output side while holding the other side constantly high. Here is how it performs the following actions:

  • Joint brake (in1 = in2): both H-bridges alternate between high impedance and driving low at the same synchronized duty cycle.
  • Joint “forward” (in1 = 0, in2 = 1): H-bridge 1 alternates between high impedance and driving low while H-bridge 2 drives high.
  • Joint “reverse” (in1 = 1, in2 = 0): H-bridge 2 alternates between high impedance and driving low while H-bridge 1 drives high.

The red/green LEDs on the daughter motor-driver board will not function in joint motor mode, nor will current-sensing. To run your X2 in joint motor mode, you should connect one side of your motor to the two M1 outputs and the other side of your motor to the two M2 outputs.

Values sent: in1 (1 bit), in2 (1 bit), PWM (8 bits)

command byte = 144 | (in1 bit << 2) | (in2 bit << 1) | MSB of PWM

data byte = 7 lower bits of PWM byte