ATmega644PA datasheet(297/468 Pages) ATMEL

297 / 468 page

297

8152G–AVR–11/09

ATmega164PA/324PA/644PA/1284P

Notes:

1. Program the Fuse bits and Boot Lock bits before programming the LB1 and LB2.

2. “1” means unprogrammed, “0” means programmed

26.2

Fuse Bits

The ATmega164PA/324PA/644PA/1284P has four Fuse bytes. Table 26-3 - Table 26-5

describe briefly the functionality of all the fuses and how they are mapped into the Fuse bytes.

Note that the fuses are read as logical zero, “0”, if they are programmed.

Note:

1. See ”System and Reset Characteristics” on page 334 for BODLEVEL Fuse decoding.

BLB1 Mode

BLB12

BLB11

No restrictions for SPM or (E)LPM accessing the Boot Loader

section.

SPM is not allowed to write to the Boot Loader section.

SPM is not allowed to write to the Boot Loader section, and

(E)LPM executing from the Application section is not allowed to

read from the Boot Loader section. If Interrupt Vectors are

placed in the Application section, interrupts are disabled while

executing from the Boot Loader section.

(E)LPM executing from the Application section is not allowed to

read from the Boot Loader section. If Interrupt Vectors are

placed in the Application section, interrupts are disabled while

executing from the Boot Loader section.

Table 26-2.

Lock Bit Protection Modes

(1)(2) (Continued)

Memory Lock Bits

Protection Type

Table 26-3.

Extended Fuse Byte

Fuse Low Byte

Bit No

Description

Default Value

–7

–

–6

–

–5

–

–4

–

–3

–

BODLEVEL2(1)

Brown-out Detector trigger level

1 (unprogrammed)

BODLEVEL1(1)

Brown-out Detector trigger level

1 (unprogrammed)

BODLEVEL0(1)

Brown-out Detector trigger level

1 (unprogrammed)

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