| 摘要 |
<p>PURPOSE:To realize an effective resetting action of a microprocessor by using a charging/discharging circuit, a waveform shaping circuit and a reset signal generating circuit and selecting the threshold value of the waveform shaping circuit. CONSTITUTION:When a power supply is applied to a terminal equipment, the output voltage of the charging/discharging circuit 22 of a resetting circuit 14 is less than the threshold value of a Schmitt circuit 35. Therefore the output voltage (f) of the circuit 35 is equal to '0' regardless of the value of the data signal (a) received from a MODEM of the circuit 14. While the output of a NOR gate 46 is equal to '1'. Then the output (g) of a differentiating circuit 52 varies and a transistor TR 56 conducts with a microprocessor reset respectively. In case the microprocessor of either one of terminal equipments has runaway and the signals of '0' are continuously supplied to the circuit 14, the output voltage of the circuit 22 exceeds the threshold value of the circuit 35. As a result, the output (f) of the circuit 35 is equal to '0'. Then the output (f) is equal to '1' when the signal received from the MODEM is changed to '1'. Thus a reset signal is produced from a reset signal generating circuit 60.</p> |
