Reset pin on MC9S12XEQ pulls down for unknown reason

[programmer]

Hello,

I've started writing code for the MC9S12XEQ.

The code resets the COP watchdog timer by writing 0x55 and 0xAA, but for unknown reason, the RESET pin pulls down for 1.5 ms every 50 milliseconds.

This is also happens whenever the debugger stops the MCU (which is logical, but it also happens when the debugger is not connected).

How can I keep the RESET pin always up?

Thank you.

[kef · Accepted solution]

S12XE pulls RESET pin low when internal reset occurs. It could be illegal address reset, COP or clock monitor reset.