TMS320F280049: Methods to enable or disable PWM output.

Hitoshi-San,

Thank you for your question. There are a few different ways to disable the PWM output.

1. Trip-zone(TZ)
   1. TZFRC
      1. The best way if you do not need TZFRC for another function.
   2. Why use the trip-zone?
      1. It is very fast 
      2. It is the last sub-module in the PWM module so nothing else can change the PWM output after the TZ takes effect
   3. Why not to use the trip-Zone?
      1. Sometimes the trip-zone software force is needed for another system function.
2. Action qualifier(AQ)
   1. AQSFRC
      1. This allows the output to be forced high or low, if another event happens after the AQSFRC event the event will change the PWM output
   2. AQCSFRC 
      
      1. This is the same as AQSFRC, but the PWM action is latched. If another event comes afterwards the AQCSFRC event still controls the PWM output.
   3. Why to use the Action qualifier?
      1. Its simple and easy to use
   4. Why not to use the action qualifier
      1. The Action qualifier is one of the first sub-modules in the PWM module. This means that any module that comes after it(the trip-zone, digital compare, dead-band, or PWM-chopper submodules) could still affect the PWM output. 
         1. If the dead-band is used in a complementary mode it will continue to function even if ePWMxA and ePWMxB are forced low by the AQ. In complimentary modes only one channel ePWMxA or ePWMxB is used to create a new pair of complemtary outputs  which means it is impossible to force both ePWM channels low using the AQ when the Dead-band is used.
3. GPIO Mux
   1. GPxMUX
      1. The GPxMUX register can be used to disconnect the GPIO buffer from the PWM output. Switch from the PWM option to the GPIO option. COnfigure the GPIO data register to force 0 and set the GPxDIR register to an output. 
   2. Why to use GPIO Mux?
      1. Use this when the other options above do not work for your system
   3. Why not to use the GPIO Mux?
      1. All other PWM functions will be disabled, including asynchronous trips. Switching from your forced condition and back to the active PWM output can be more difficult than the option above.

Please let me know if you have any other questions.

Regards,
Cody