AT90PWM2B-16SU View Datasheet(PDF) - Atmel Corporation

Part Name

Description

Manufacturer

AT90PWM2B-16SU

8-bit Atmel Microcontroller with 8K Bytes In-System Programmable Flash

Atmel Corporation 

AT90PWM2/3/2B/3B

9.0.3

Table 9-1. Reset Characteristics(1)

Symbol Parameter

Condition

Min. Typ.

Max. Units

VPOT

Power-on Reset Threshold

Voltage (rising)

Power-on Reset Threshold

Voltage (falling)(2)

1.4

2.3

V

1.3

2.3

V

VRST

tRST

RESET Pin Threshold Voltage

Minimum pulse width on RESET

Pin

0.2Vcc

0.85Vcc V

400

ns

VPOR

VCC start voltage to ensure

internal Power-on RESET signal

-0.05 GND +0.05

V

VCCRR

VCC Rise Rate to ensure internal

Power-on RESET signal

0.3

V/ms

Notes: 1. Values are guidelines only..

2. The Power-on Reset will not work unless the supply voltage has been below VPOT (falling)

Power-on Reset

A Power-on Reset (POR) pulse is generated by an On-chip detection circuit. The detection level

is defined in Table 9-1. The POR is activated whenever VCC is below the detection level. The

POR circuit can be used to trigger the start-up Reset, as well as to detect a failure in supply

voltage.

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

VCC

VPOT

RESET

VRST

TIME-OUT

tTOUT

INTERNAL

RESET

47

4317K–AVR–03/2013

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