Datasheet

Clock Functions
Technical Data MC68HC912D60A — Rev. 3.1
173 Clock Functions Freescale Semiconductor
Always reads $00.
Writing $55 to this address is the first step of the COP watchdog
sequence.
Writing $AA to this address is the second step of the COP watchdog
sequence. Other instructions may be executed between these writes
but both must be completed in the correct order prior to time-out to
avoid a watchdog reset. Writing anything other than $55 or $AA
causes a COP reset to occur.
Bit 7654321Bit 0
Bit 7654321Bit 0
RESET: 00000000
COPRST — Arm/Reset COP Timer Register $0017