external reset and watchdog reset flags

shaking928 — Mon, 20 Dec 2021 07:08:20 GMT

Does anybody know flags for external reset and watchdog reset for MC9S12XET MCUs? I cannot find them in MC9S12XEP100 Reference Manual.

Re: external reset and watchdog reset flags

danielmartynek — Mon, 20 Dec 2021 10:52:02 GMT

Hello @shaking928,

There are these reset vectors:

So, if the COP is the source of the reset, it will fetch the COP vector.

Please read the RM, Section 11.5.1 Description of Reset Operation

"External circuitry connected to the RESET pin should be able to raise the
signal to a valid logic one within 64 SYSCLK cycles after the low drive is
released by the MCU. If this requirement is not adhered to the reset source
will always be recognized as “External Reset” even if the reset was initially
caused by an other reset source."

Explained in details here:

https://community.nxp.com/t5/S12-MagniV-Microcontrollers/S12-FAMILY-DEVICES-COP-RECOGNITION-CONSIDERATIONS-v2-0-pdf/ta-p/1113092

Simple S12XEP100 COP example is attached,

Regards,

Daniel

topic external reset and watchdog reset flags in S12 / MagniV Microcontrollers

external reset and watchdog reset flags

Re: external reset and watchdog reset flags