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Reading the Flash
Reading the EEPROM
Programming the
Fuse Low Bits
ATmega128
296
Figure 138. Programming the EEPROM Waveforms
A
0x11
DATA
XA1
XA0
BS1
XTAL1
WR
RDY/BSY
RESET +12V
OE
PAGEL
BS2
The algorithm for reading the Flash memory is as follows (refer to
page 293
for details on Command and Address loading):
1. A: Load Command "0000 0010".
2. G: Load Address High Byte ($00 - $FF).
3. B: Load Address Low Byte ($00 - $FF).
4. Set OE to "0", and BS1 to "0". The Flash word low byte can now be read at DATA.
5. Set BS1 to "1". The Flash word high byte can now be read at DATA.
6. Set OE to "1".
The algorithm for reading the EEPROM memory is as follows (refer to
on page 293
for details on Command and Address loading):
1. A: Load Command "0000 0011".
2. G: Load Address High Byte ($00 - $FF).
3. B: Load Address Low Byte ($00 - $FF).
4. Set OE to "0", and BS1 to "0". The EEPROM Data byte can now be read at DATA.
5. Set OE to "1".
The algorithm for programming the Fuse Low bits is as follows (refer to
on page 293
for details on Command and Data loading):
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 "0" and BS2 to "0".
4. Give WR a negative pulse and wait for RDY/BSY to go high.
G
B
C
E
ADDR. HIGH
ADDR. LOW
DATA
XX
K
B
C
E
L
ADDR. LOW
DATA
XX
"Programming the Flash" on
"Programming the Flash"
"Programming the Flash"
2467S–AVR–07/09
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