Datasheet
189
ATmega323(L)
1457E–11/01
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 185 for details on Command loading):
1. A: Load Command “0000 0100”.
2. 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).
Bit 7 = BODLEVEL Fuse bit
Bit 6 = BODEN Fuse bit
Bit 3..0 = CKSEL3..0 Fuse bits
3. 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).
Bit 7 = OCDEN Fuse bit
Bit 6 = JTAGEN Fuse bit
Bit 5 = SPIEN Fuse bit
Bit 3 = EESAVE Fuse bit
Bit 2..1 = BOOTSZ1..0 Fuse bits
Bit 0 = BOOTRST Fuse bit
4. 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).
Bit 5 = Boot Lock Bit12
Bit 4 = Boot Lock Bit11
Bit 3 = Boot Lock Bit02
Bit 2 = Boot Lock Bit01
Bit 1 = Lock Bit2
Bit 0 = Lock Bit1
5. Set OE
to “1”.
Reading the Signature Bytes The algorithm for reading the Signature bytes is as follows (refer to Programming the
Flash for details on Command and Address loading):
1. A: Load Command “0000 1000”.
2. C: Load Address Low Byte ($00 - $02).
3. Set OE
to “0”, and BS1 to “0”. The selected Signature byte can now be read at
DATA.
4. Set OE
to “1”.
Reading the Calibration Byte The algorithm for reading the Calibration byte is as follows (refer to Programming the
Flash for details on Command and Address loading):
1. A: Load Command “0000 1000”.
2. C: Load Address Low Byte, $00.
3. Set OE
to “0”, and BS1 to “1”. The Calibration byte can now be read at DATA.
4. Set OE to “1”.