Sleep Mode: To minimize power consumption when the motor is not in use, this input disables much of the
internal circuitry including the output FETs, current regulator,
and charge pump. A logic low on the Sleep pin puts the A4984
into Sleep mode. A logic high allows normal operation, as well as
start-up (at which time the A4984 drives the motor to the Home
microstep position). When emerging from Sleep mode, in order
to allow the charge pump to stabilize, provide a delay of 1 ms
before issuing a Step command.