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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.
+5V
+5V
IC4
VCC
CD
RESET
+
GND
C2
RESET IC
(1)
At power on, voltage-detector circuit IC4 (M51953BL) outputs a LOW signal from its OUT terminal.
The following formula is used by capacitor C2 (0.47 F).
T = 0.34 C2 (pF) [ s] = 160ms
(2)
The LOW signal resets the CPU and the mechanism drive circuits.
(3)
The LOW signal sets S-RAM into backup status.
IC5 : CPU
CPU
RES
RESO
DD3
Protection
Circuit
Fig. 2-10 Power-On Reset Circuit
– 24 –
+5V
+5V
VCC
S-RAM
IC1
IC10
RESET
Gate
Array
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