Atmel ATmega48PV Manual page 306

25.7.8 Programming the Fuse Low Bits
25.7.9 Programming the Fuse High Bits
25.7.10 Programming the Extended Fuse Bits
25.7.11 Programming the Lock Bits
8025I–AVR–02/09
The algorithm for programming the Fuse Low bits is as follows (refer to
on page 302 for details on Command and Data loading):
1. A: Load Command "0100 0000".
2. C: Load Data Low Byte. Bit n = "0" programs and bit n = "1" erases the Fuse bit.
3. Give WR a negative pulse and wait for RDY/BSY to go high.
The algorithm for programming the Fuse High bits is as follows (refer to
Flash" on page 302 for details on Command and Data loading):
1. A: Load Command "0100 0000".
2. C: Load Data Low Byte. Bit n = "0" programs and bit n = "1" erases the Fuse bit.
3. Set BS1 to "1" and BS2 to "0". This selects high data byte.
4. Give WR a negative pulse and wait for RDY/BSY to go high.
5. Set BS1 to "0". This selects low data byte.
The algorithm for programming the Extended Fuse bits is as follows (refer to
Flash" on page 302 for details on Command and Data loading):
1. 1. A: Load Command "0100 0000".
2. 2. C: Load Data Low Byte. Bit n = "0" programs and bit n = "1" erases the Fuse bit.
3. 3. Set BS1 to "0" and BS2 to "1". This selects extended data byte.
4. 4. Give WR a negative pulse and wait for RDY/BSY to go high.
5. 5. Set BS2 to "0". This selects low data byte.
Figure 25-5. Programming the FUSES Waveforms
A C
0x40 DATA
DATA
XA1
XA0
BS1
BS2
XTAL1
WR
RDY/BSY
RESET +12V
OE
PAGEL
The algorithm for programming the Lock bits is as follows (refer to
page 302 for details on Command and Data loading):
ATmega48P/88P/168P/328P
Write Fuse Low byte
A C
XX 0x40 DATA
"Programming the Flash"
Write Fuse high byte
A C
XX 0x40 DATA
"Programming the Flash" on
"Programming the
"Programming the
Write Extended Fuse byte
XX
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