ATMEGA1284P_14 Datasheet, PDF (303/380 Pages) ATMEL Corporation – High-performance, Low-power AVR

ATmega1284P
25.7.12 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 297 for details on Command loading):
1. A: Load Command “0000 0100”.
2. Set OE to “0”, and BS2, BS1 to “00”. The status of the Fuse Low bits can now be read at
DATA (“0” means programmed).
3. Set OE to “0”, and BS2, BS1 to “11”. The status of the Fuse High bits can now be read at
DATA (“0” means programmed).
4. Set OE to “0”, and BS2, BS1 to “10”. The status of the Extended Fuse bits can now be
read at DATA (“0” means programmed).
5. Set OE to “0”, and BS2, BS1 to “01”. The status of the Lock bits can now be read at DATA
(“0” means programmed).
6. Set OE to “1”.
Figure 25-6. Mapping Between BS1, BS2 and the Fuse and Lock Bits During Read
Fuse Low Byte
0
Extended Fuse Byte
1
BS2
Lock Bits
0
0
DATA
1
Fuse High Byte
1
BS1
BS2
25.7.13 Reading the Signature Bytes
25.7.14
The algorithm for reading the Signature bytes is as follows (refer to ”Programming the Flash” on
page 297 for details on Command and Address loading):
1. A: Load Command “0000 1000”.
2. B: Load Address Low Byte (0x00 - 0x02).
3. Set OE to “0”, and BS 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” on
page 297 for details on Command and Address loading):
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”.
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