SCTimer/PWM Run the SCT

  1. Configure the SCT (see SCTimer/PWM Configure the SCT).
  2. Write to the STATE register to define the initial state. By default the initial state is state 0.
  3. To start the SCT, write to the CTRL register:
    • Clear the counters.
    • Clear or set the STOP_L and/or STOP_H bits.
      Note: The counter starts counting once the STOP bit is cleared as well. If the STOP bit is set, the SCT waits instead for an event to occur that is configured to start the counter.
    • For each counter, select unidirectional or bidirectional counting mode (field BIDIR_L and/or BIDIR_H).
    • Select the prescale factor for the counter clock (CTRL register).
    • Clear the HALT_L and/or HALT_H bit. By default, the counters are halted and no events can occur.
  4. To stop the counters by software at any time, stop or halt the counter (write to STOP_L and/or STOP_H bits or HALT_L and/or HALT_H bits in the CTRL register).
    • When the counters are stopped, both an event configured to clear the STOP bit or software writing a zero to the STOP bit can start the counter again.
    • When the counter are halted, only a software write to clear the HALT bit can start the counter again. No events can occur.
    • When the counters are halted, software can set any SCT output HIGH or LOW directly by writing to the OUT register.

The current state can be read at any time by reading the STATE register.

To change the current state by software (that is independently of any event occurring), set the HALT bit and write to the STATE register to change the state value. Writing to the STATE register is only allowed when the counter is halted (the HALT_L and/or HALT_H bits are set) and no events can occur.