AT90SCR100 datasheet(53/433 Pages) ATMEL

No. de pieza	AT90SCR100

Descripción Electrónicos	8-bit Microcontroller for Smart Card Readers

PDF	433 Pages

Scroll/Zoom	100%

Fabricante Electrónico	ATMEL [ATMEL Corporation]

Página de inicio	http://www.atmel.com

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53 / 433 page

TPR0327AY–SMS–30Jan09

AT90SCR100

A Power-on Reset (POR) circuit ensures that the device is reset from Power-on. Reaching the

Power-on Reset threshold voltage invokes the delay counter, which determines how long the

device is kept in RESET after VCC rise. The RESET signal is activated again, without any delay,

when VCC decreases below the detection level.

Figure 9-2.

MCU Start-up, RESET Tied to VCC

Figure 9-3.

MCU Start-up, RESET Extended Externally

9.2.2

External Reset

An External Reset is generated by a low level on the RESET pin. Reset pulses longer than the

minimum pulse width (see Table 9-1) 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 – VRST – on its positive edge, the delay counter starts the MCU after

the Time-out period – tTOUT – has expired.

RESET

TIME-OUT

INTERNAL

RESET

TOUT

POT

RST

RESET

TIME-OUT

INTERNAL

RESET

TOUT

POT

RST

V CC

AT90SCR100 Datasheet(PDF) 53 Page - ATMEL Corporation