atmega3250v-8auatmega325v-8ai ATMEL Corporation, atmega3250v-8auatmega325v-8ai Datasheet - Page 275

• Manufacturer Part Number: atmega3250v-8auatmega325v-8ai
• Description: Atmega3250 8-bit Microcontroller With In-system Programmable Flash
• Manufacturer: ATMEL Corporation

27.6.10
27.6.11
27.6.12
2570L–AVR–08/07
Programming the Extended Fuse Bits
Programming the Lock Bits
Reading the Fuse and Lock Bits
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 271
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 27-5. Programming the FUSES Waveforms
The algorithm for programming the Lock bits is as follows (refer to
page 271
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 271
(LB1 and LB2 is programmed), it is not possible to program the Boot Lock bits by any
External Programming mode.
RESET +12V
RDY/BSY
PAGEL
XTAL1
DATA
for details on Command and Data loading):
XA1
XA0
BS1
BS2
WR
OE
for details on Command loading):
0x40
A
for details on Command and Data loading):
DATA
C
Write Fuse Low byte
XX
0x40
A
ATmega325/3250/645/6450
DATA
C
Write Fuse high byte
XX
“Programming the Flash” on
0x40
A
“Programming the Flash”
DATA
C
Write Extended Fuse byte
“Programming the
XX
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