µVision® IDE & Debugger

Watchdog Timer Simulation

The µVision debugger simulates the on-chip watchdog timer found in many 8051, 251, 166, and ARM microcontrollers.

All registers are fully simulated and the MCU resets when the timer overflows or underflows (as specified). Reset, overflow, and the timer may be displayed in real-time.

There is no standard for enabling a watchdog timer. Some devices require a combination of writes to the watchdog's control register, some allow enabling the watchdog only briefly after reset, and some use external hardware pins to enable or disable the timer. The µVision Debugger supports all of these techniques.

Resetting the watchdog timer is usually straight forward in that a special value or sequence of balues is written to a control register that resets the watchdog timer. This counter must be reset periodically by your application program.