Factors causing / HRST of MPC8270

[HiroyukiO]

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

[Bulat]

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

Regards,

Bulat

[Ohata]

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

[Bulat]

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