ATMEGA640 datasheet(361/436 Pages) MICROCHIP

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361

ATmega640/V-1280/V-1281/V-2560/V-2561/V [DATASHEET]

DS40002211A

31.5.2

Enhanced Power-On Reset

This implementation of power-on reset exists in newer versions of ATmega640/1280/1281/2560/2561. The table

below describes the characteristics of this power-on reset and it is valid for the following devices only:

•

ATmega640: revision B and newer

•

ATmega1280: revision B and newer

•

ATmega1281: revision B and newer

•

ATmega2560: revision F and newer

•

ATmega2561: revision F and newer

Table 31-5.

Characteristics of Enhanced Power-On Reset. TA= -40 to +85°C.

Notes: 1. Values are guidelines only.

2. Threshold where device is released from reset when voltage is rising.

3. The power-on reset threshold voltage (falling) will not work unless the supply voltage has been below VPOT.

Note:

1. VBOT may be below nominal minimum operating voltage for some devices. For devices where this is the case, the

device is tested down to VCC = VBOT during the production test. This guarantees that a Brown-Out Reset will occur

before VCC drops to a voltage where correct operation of the microcontroller is no longer guaranteed. The test is

performed using BODLEVEL = 110 for 4MHz operation of ATmega640V/1280V/1281V/2560V/2561V, BODLEVEL

= 101 for 8MHz operation of ATmega640V/1280V/1281V/2560V/2561V and ATmega640/1280/1281, and

BODLEVEL = 100 for 16MHz operation of ATmega640/1280/1281/2560/2561.

31.6 2-wire Serial Interface Characteristics

Table 31-7 on page 362 describes the requirements for devices connected to the 2-wire Serial Bus. The ATme-

ga640/1280/1281/2560/2561 2-wire Serial Interface meets or exceeds these requirements under the noted

conditions.

Timing symbols refer to Figure 31-6 on page 363.

Symbol

Parameter

Min.(1)

Typ.(1)

Max.(1)

Units

VPOT

Power-on Reset Threshold Voltage (rising)(2)

1.1

1.4

1.6

Power-on Reset Threshold Voltage (falling)(3)

0.6

1.3

1.6

VPSR

Power-On Slope Rate

0.01

V/ms

Table 31-6.

BODLEVEL Fuse Coding(1)

BODLEVEL 2:0 Fuses

Min. VBOT

Typ. VBOT

Max. VBOT

Units

111

BOD Disabled

110

1.7

1.8

2.0

101

2.5

2.7

2.9

100

4.1

4.3

4.5

011

Reserved

010

001

000

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