Datasheet

309
8021G–AVR–03/11
ATmega329P/3290P
Figure 27-6. Mapping Between BS1, BS2 and the Fuse and Lock Bits During Read
27.7.13 Reading the Signature Bytes
The algorithm for reading the Signature bytes is as follows (refer to ”Programming the Flash” on
page 303 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 BS1 to “0”. The selected Signature byte can now be read at DATA.
4. Set OE
to “1”.
27.7.14 Reading the Calibration Byte
The algorithm for reading the Calibration byte is as follows (refer to ”Programming the Flash” on
page 303 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”.
27.7.15 Parallel Programming Characteristics
Lock Bits
0
1
BS2
Fuse High Byte
0
1
BS1
DATA
Fuse Low Byte
0
1
BS2
Extended Fuse Byte
Table 27-15. Parallel Programming Characteristics, V
CC
= 5V ± 10%
Symbol Parameter Min Typ Max Units
V
PP
Programming Enable Voltage 11.5 12.5 V
I
PP
Programming Enable Current 250 μA
t
DVXH
Data and Control Valid before XTAL1 High 67 ns
t
XLXH
XTAL1 Low to XTAL1 High 200 ns
t
XHXL
XTAL1 Pulse Width High 150 ns
t
XLDX
Data and Control Hold after XTAL1 Low 67 ns
t
XLWL
XTAL1 Low to WR Low 0 ns
t
XLPH
XTAL1 Low to PAGEL high 0 ns
t
PLXH
PAGEL low to XTAL1 high 150 ns