ATmega16 datasheet(265/315 Pages) ATMEL

265 / 315 page

265

ATmega16(L)

2466E–AVR–10/02

Programming the Lock Bits

The algorithm for programming the Lock bits is as follows (refer to “Programming the

Flash” on page 260 for details on Command and Data loading):

A: Load Command “0010 0000”.

C: Load Data Low Byte. Bit n = “0” programs the Lock bit.

Give WR a negative pulse and wait for RDY/BSY to go high.

The Lock bits can only be cleared by executing Chip Erase.

Reading the Fuse and Lock

Bits

The algorithm for reading the Fuse and Lock bits is as follows (refer to “Programming

the Flash” on page 260 for details on Command loading):

A: Load Command “0000 0100”.

Set OE to “0”, BS2 to “0” and BS1 to “0”. The status of the Fuse Low bits can

now be read at DATA (“0” means programmed).

Set OE to “0”, BS2 to “1” and BS1 to “1”. The status of the Fuse High bits can

now be read at DATA (“0” means programmed).

Set OE to “0”, BS2 to “0” and BS1 to “1”. The status of the Lock bits can now be

read at DATA (“0” means programmed).

Set OE to “1”.

Figure 132. Mapping between BS1, BS2 and the Fuse- and Lock Bits during Read

Reading the Signature Bytes

The algorithm for reading the Signature bytes is as follows (refer to “Programming the

Flash” on page 260 for details on Command and Address loading):

A: Load Command “0000 1000”.

B: Load Address Low Byte ($00 - $02).

Set OE to “0”, and BS1 to “0”. The selected Signature byte can now be read at

DATA.

Set OE to “1”.

Reading the Calibration Byte

The algorithm for reading the Calibration byte is as follows (refer to “Programming the

Flash” on page 260 for details on Command and Address loading):

A: Load Command “0000 1000”.

B: Load Address Low Byte, $00.

Set OE to “0”, and BS1 to “1”. The Calibration byte can now be read at DATA.

Set OE to “1”.

Fuse Low Byte

Lock Bits

BS2

Fuse High Byte

BS1

DATA

ATMEGA16 Datasheet(PDF) 265 Page - ATMEL Corporation

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