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External reset, Figure 25) – Rainbow Electronics AT90LS2343 User Manual

Page 22

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22

AT90S/LS2323/2343

1004D–09/01

Figure 25. MCU Start-up, RESET Tied to V

CC

.

Figure 26. MCU Start-up, RESET Controlled Externally

External Reset

An external reset is generated by a low level on the RESET pin. Reset pulses longer
than 50 ns will generate a reset, even if the clock is not running. Shorter pulses are not
guaranteed to generate a reset. When the applied signal reaches the Reset Threshold
Voltage (V

RST

) on its positive edge, the delay timer starts the MCU after the Time-out

period t

TOUT

has expired.

Figure 27. External Reset during Operation

VCC

RESET

TIME-OUT

INTERNAL

RESET

t

TOUT

V

POT

V

RST

VCC

RESET

TIME-OUT

INTERNAL

RESET

t

TOUT

V

POT

V

RST