SWRU626 December 2025 CC3501E , CC3551E
A capture request signal can be routed from RFCORE to trigger samplestamp capture. The EVENT:PDMSTPSEL0 register selects the RFCORE signal to be used. Whenever this capture request signal is high:
Also, on the first WCLK edge of each frame, the current value of PDM:STPXCNT is captured in PDM:STPXPER, and PDM:STPXCNT then restarts counting from 0.
Using these values, a fixed-point samplestamp value can be calculated:
PDM:STPWCNTCAPT0 + (PDM:STPXCNTCAPT0 / PDM:STPXPER)
Notice that the value of PDM:STPXPER will not normally be captured at the same time as the other values. Therefore, PDM:STPXPER can be less than PDM:STPXCNTCAPT.