SPRUHM9H October 2014 – May 2024 TMS320F28075 , TMS320F28075-Q1 , TMS320F28076
The ePWM synchronization scheme allows for increased flexibility of synchronization of the ePWM modules. Each ePWM module has a synchronization input (SYNCI), a synchronization output (SYNCO) and a peripheral synchronization output (SYNCPER). In Figure 14-7, EXTSYNCIN1 is sourced from INPUTXBAR5 and EXTSYNCIN2 is sourced from INPUTXBAR6, which can be configured to select any GPIO as the synchronization input. When configuring the sync chain propagation path using the SYNCSEL registers, make sure that the longest path does not exceed four ePWM/eCAP modules.
Each ePWM module can be configured to use or ignore the synchronization input. If the TBCTL[PHSEN] bit is set, then the time-base counter (TBCTR) of the ePWM module is automatically loaded with the phase register (TBPHS) contents when one of the following conditions occur:
The delay from internal control module to target modules is given by:
This feature enables the ePWM module to be automatically synchronized to the time base of another ePWM module. Lead or lag phase control can be added to the waveforms generated by different ePWM modules to synchronize them. In up-down-count mode, the TBCTL[PHSDIR] bit configures the direction of the time-base counter immediately after a synchronization event. The new direction is independent of the direction prior to the synchronization event. The PHSDIR bit is ignored in count-up or count-down modes. See Figure 14-8 through Figure 14-11 for examples.
Clearing the TBCTL[PHSEN] bit configures the ePWM to ignore the synchronization input pulse. The synchronization pulse can still be allowed to flow-through to the EPWMxSYNCO and be used to synchronize other ePWM modules. In this way, a controller time-base (for example, ePWM1) can be set up and downstream modules (ePWM2 - ePWMx) can run in synchronization with the controller. See Section 14.13 for more details on synchronization strategies.