ATMEGA48V_11 ATMEL [ATMEL Corporation], ATMEGA48V_11 Datasheet - Page 297

• Manufacturer Part Number: ATMEGA48V_11
• Description: 8-bit Atmel Microcontroller with 4/8/16K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

28.7.11
28.7.12
28.7.13
2545T–AVR–05/11
Programming the lock bits
Reading the fuse and lock bits
Reading the signature bytes
The algorithm for programming the Lock bits is as follows (refer to
page 292
1. A: Load Command “0010 0000”.
2. C: Load Data Low Byte. Bit n = “0” programs the Lock bit. If LB mode 3 is programmed
3. Give WR a negative pulse and wait for RDY/BSY to go high.
The Lock bits can only be cleared by executing Chip Erase.
The algorithm for reading the Fuse and Lock bits is as follows (refer to
on page 292
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
3. Set OE to “0”, BS2 to “1” and BS1 to “1”. The status of the Fuse High bits can now be
4. Set OE to “0”, BS2 to “1”, and BS1 to “0”. The status of the Extended Fuse bits can now
5. Set OE to “0”, BS2 to “0” and BS1 to “1”. The status of the Lock bits can now be read at
6. Set OE to “1”.
Figure 28-6. Mapping between BS1, BS2 and the fuse and lock bits during read.
The algorithm for reading the Signature bytes is as follows (refer to
page 292
1. A: Load Command “0000 1000”.
2. B: Load Address Low Byte (0x00 - 0x02).
3. Set OE to “0”, and BS1 to “0”. The selected Signature byte can now be read at DATA.
4. Set OE to “1”.
(LB1 and LB2 is programmed), it is not possible to program the Boot Lock bits by any
External Programming mode.
read at DATA (“0” means programmed).
read at DATA (“0” means programmed).
be read at DATA (“0” means programmed).
DATA (“0” means programmed).
for details on Command and Data loading):
for details on Command and Address loading):
for details on Command loading):
Extended fuse byte
Fuse high byte
Fuse low byte
Lock bits
BS2
BS2
0
1
0
1
BS1
ATmega48/88/168
0
1
“Programming the flash” on
“Programming the flash” on
“Programming the flash”
DATA
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