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eTPU PWM input sampling target on MPC5746R

Question asked by Qi Jiang on Sep 25, 2017
Latest reply on Mar 28, 2018 by Terry Peterson

Hi, NXP talents


Please help on issue found on eTPU PWM input sampling target on MPC5746R.

Below is the details:


This is an VCU product.

Actually we have loaded cyclic task scheduling and several interrupts (exp. CAN receiver, LIN, PIT timer) running on MPC5746R. beside that, we have configured eTPU as PWM input capture operation mode.

we assign two eTPU channel to sample the outside two PWM (250Hz, duty cycle changed with 1% accuracy) signals. while we can make sure the configuration of both eTPU channel is the same.  however, we randomly get a strange issue found on one channel that counter overflow (PWM duty cycle jump to 100% ) occurs, while the other channel operate normal capture behavior. (Please refer to the attachment pic). 


This is quite strange when we have applied functional safety related code inside, cause if we remove that, both two channel eTPU capture operate find.


Actually we have deployed several functional safety related code, RAM fault, RAP(RAM Access Protection), Flash fault, Core0 & Core1 challenge & Response, enable Core2 (Lock step), core1 & core0 stack monitor.


I have spent two weeks to debug this issue. right now I have made a progress when I disable Core0 & Core2 initialization section (MC_ME module entry block) and disable Core1 ->Core0 challenge & Response inter-check. Then I found the channel overflow issue almostly dissappeared. but still can capture one if monitor long time.


Here I need NXP talents' help, and explain how to find the way to debug.