| 摘要 |
A flag setting circuit for a microcontroller, which can be set with a HALT mode flag and a watchdog timer overflow flag by using a system power-on signal, an external reset signal, a watchdog timer overflow signal inside the microcontroller, a clear instruction for watchdog timer, a HALT mode instruction, and a wake-up signal. The setting circuit for the watchdog timer overflow flag includes a reset signal generator, a watchdog timer, a clear signal generator, a flag clear circuit, and a register circuit. The setting circuit for the HALT mode flag includes a HALT mode discerning circuit, a flag clear circuit, and a register circuit. The frequency source of the watchdog timer is provided by means of a frequency from the system oscillator divided with four, or by using a frequency of RC oscillator built in the system. Under the HALT mode, the RC oscillator is selected. By means of the HALT mode flag and the watchdog timer overflow flag, the operation condition of the system hardware can be discerned. |
