Star Micronics TSP200 technical manual Power-On Reset Circuit

PRINCIPLES OF OPERATION

2-4. Power-On Reset Circuit

The power-on reset signal initializes all elements so as to protect against possible operating errors at power-on. The signal is held for approximately 160ms when power comes on. The reset circuit is shown below.

Fig. 2-13 Power-On Reset Circuit

+5V

+

C9

	+5V
IC3	+5V
	VCC
CD	OUT
	GND

Drive circuit IC1 : CPU

CPU

RESRESO

+5V

+5V

IC4

RESET

Gate array

RESET IC

D1

Fig. 2-13 Power-On Reset Circuit

1At power-on, voltage detector IC3 (M51953BL) outputs a LOW signal from its OUT terminal. The signal is held for approximately 160ms by the action of capacitor C9 (0.47µF), in accordance with the following relation:

T = 0.34 × C9 (pF) [µs] = 160ms

2The LOW signal generates reset of the CPU and gate array, and stops operation of the mechanism drive circuitry.

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