Star Micronics TSP400 Bedienungsanleitung PDF herunterladen (Seite 31)

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THEORY OF OPERATION

2-4. Power-On Reset Circuit

Immediately following power-on the printer executes a power-on reset, initializing all circuit elements. The power-on

reset serves as protection against operational errors. The power-on RESET signal is maintained for approximately 160ms.

The reset circuit is illustrated below.

Fig. 2-10 Power-On Reset Circuit

1 At power on, voltage-detector circuit IC4 (M51953BL) outputs a LOW signal from its OUT terminal. The signal

lasts for approximately 160ms, as determined by capacitor C2 (0.47µF):

T = 0.34 × C2 (pF) [µs] = 160ms

2 The LOW signal resets the CPU and the mechanism drive circuits, and sets S-RAM into backup state.

+5V

IC4

GND

+5V

VCC

RESET

DD3

IC5 : CPU

RES

RESO

RESET

VCC

S-RAM

Gate

array

IC1

RESET IC

IC10

Back-up

Circuit

CPU

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Star Micronics TSP400 Bedienungsanleitung Seite 31