| 摘要 |
PURPOSE:To cope with the runaway of a microprogram without providing an exclusive terminal by providing a microcomputer with a means for selecting either one of system initialization or interruption in accordance with the overflow of a watch-dog timer circuit. CONSTITUTION:A time base counter 201 in the watch-dog timer(WDT) circuit 130 counts up clocks CLK 210 and outputs a specified WDT count lock 211 from its output tap. When a WDT clear signal(WDTCLR) 214 or a reset signal (RESET) 145 is inputted to an OR gate 205, a clear signal 216 is activated and a WDT 202 is initialized. If the WDT 202 continues counting-up operation without being initialized and generates overflow, a WDTOUT active timer 203 is started and a flip flop(FF) 204 is reset. |
