08-12-2011, 09:30 AM
The datasheet for these chips does not make it clear. On these cheap boards there are 2 switches connected to the TQ1 and TQ2 pins of the stepper chip. The datasheet states that if these pins are driven high (5v) then the current to the motor is 20% of the value set by the resistor. What is not clear is whether this is automatic or always, ie if they are driven high is the current 100% when moving and 20% when not moving or do I have to drive these pins high when I stop sending pulses to the stepper?