topic Re: Factors causing / HRST of MPC8270 in Other NXP Products

Factors causing / HRST of MPC8270

HiroyukiO — Fri, 09 Jul 2021 06:38:06 GMT

We are investigating defects on the board. Even though / PORST is always H input to MPC8270 on the board, pulses are periodically output from / HRST and / SRST and reset is applied. What are the possible causes? ・ The pulse width of / HRST is 16us, and / SRST is almost the same. ・ The pulse interval of / HRST is more than 10 seconds, and / SRST is almost the same. ・ The power supply and clock are normal. ・ There is one CPU on the board. ・ Softwarewatchdog is invalid ・ Checkstop has not occurred Thank you

Re: Factors causing / HRST of MPC8270

Bulat — Fri, 09 Jul 2021 09:42:23 GMT

Try to read Reset Status Register (RSR) after reset, it provides information about reason of reset.

Regards,

Bulat

Re: Factors causing / HRST of MPC8270

Ohata — Mon, 12 Jul 2021 03:51:15 GMT

I checked the RSR using a debugger, but couldn't find any particular cause. I suspect Check Stop, but the output signal / CK_STP_OUT was not in Check Stop Mode either.

Thank you,

hiroyukiO

Re: Factors causing / HRST of MPC8270

Bulat — Tue, 13 Jul 2021 05:03:18 GMT

All possible reasons of HRESET assertion are listed in section 5.1.1 of the manual. Checkstop reset can happen only if you set RMR[CSRE] bit.

Regards,

Bulat