The XCMP complex waveform generator
mode is available in the type 5 ePWM and is enabled when XCMPEN is set. The main
feature of the XCMP mode is to generate multiple ePWM pulses, with high resolution
edge placement if needed, within one ePWM period.
XCMP features include:
- Up to eight counter compare
registers XCMP1-XCMP8
- High resolution (HRPWM) edge
placement support
- Up-Count counter mode support
Note: Down-Count and Up-Down-Count counter modes
are not supported
- Pulse generation is only
supported on XCMP1-8 matches (no support for counter events such as PRD and
ZRO, or T1/T2 events)
- ePWM module synchronization
is not allowed in XCMP mode
Note: The application software
must disable the ePWM synchronization when XCMP mode is
enabled.
- XCMP1-8 are loaded through
CMPA and CMPB
Note: A minimum
of 4 cycles difference (including the HR component) between adjacent
XCMP values must be maintained to make sure of minimum pulse
width.
- The eight XCMPn registers,
can be allocated to either CMPA or CMPB through the application software
configuration
- XAQCTLA and XAQCTLB registers
determine the actions taken on the ePWM output for each XCMP1-8 counter
matches
- Up to three ePWM period
cycles can be configured at once through three shadow buffers
- Each shadow buffer
contains shadow registers for XCMP1-8, XTBPRD, XAQCTLA, XAQCTLB,
CMPC, CMPD, and XMINMAX (which is used for CAPEVT signal
generation)
- Shadow buffer SHDW2
and SHDW3 can be repeated up to eight times
- All ePWM modules can be
linked to trigger the start of their shadow loading at the same time through
EPWMXLINKXLOAD