atmega3250v-8auatmega325v-8ai ATMEL Corporation, atmega3250v-8auatmega325v-8ai Datasheet - Page 276

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

27.6.13
27.6.14
276
ATmega325/3250/645/6450
Reading the Signature Bytes
Reading the Calibration Byte
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 27-6. 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 271
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”.
The algorithm for reading the Calibration byte is as follows (refer to
page 271
1. A: Load Command “0000 1000”.
2. B: Load Address Low Byte, 0x00.
3. Set OE to “0”, and BS1 to “1”. The Calibration byte can now be read at DATA.
4. Set OE to “1”.
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 Address loading):
for details on Command and Address loading):
Extended Fuse Byte
Fuse Low Byte
Fuse High Byte
Lock Bits
BS2
BS2
0
1
0
1
BS1
0
1
“Programming the Flash” on
“Programming the Flash” on
DATA
2570L–AVR–08/07