Hi experts,
Customer found that some boards work abnormally, e.g. no CAN frame output, PWM pattern abnormal, unexpected reset, when the PFC+LLC start to converter power. They found there is big noise in JTAG path (TMS, TCK, TDI and TDO). And they tried to cut the external PCB lines of JTAG, then not find failure anymore. Further, they tried to disable TDI and TDO pinmux function in their SW, and also not find failure anymore.
So I suppose that it is caused by JTAG noise and so that influent the working of MCU. I want to check with you:
1. how could the JTAG noise influent the function of MCU? Did we have similar cases before?
2. And do you have any suggestion, i.e. PCB design, to customer to improve the noise immunity capability?
Thanks,
Will
