AT90USB82/162
Figure 25-6. Mapping Between BS1, BS2 and the Fuse and Lock Bits During Read
0
Fuse Low Byte
Extended Fuse Byte
Lock Bits
0
1
1
0
DATA
BS2
BS1
Fuse High Byte
1
BS2
25.6.13 Reading the Signature Bytes
The algorithm for reading the Signature bytes is as follows (refer to “Programming the Flash” on
page 249 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”.
25.6.14 Reading the Calibration Byte
The algorithm for reading the Calibration byte is as follows (refer to “Programming the Flash” on
page 249 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”.
25.6.15 Parallel Programming Characteristics
Figure 25-7. Parallel Programming Timing, Including some General Timing Requirements
tXLWL
tXHXL
XTAL1
tDVXH
tXLDX
Data & Contol
(DATA, XA0/1, BS1, BS2)
tBVPH
tPLBX tBVWL
tWLBX
PAGEL
tPHPL
tWLWH
WR
tPLWL
WLRL
RDY/BSY
tWLRH
255
7707D–AVR–07/08
ATMEL [ ATMEL ]
