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MEGA128CAN Datasheet, PDF (335/413 Pages) ATMEL Corporation – Microcontroller WITH 128K BYTES OF ISP FLASH AND CAN CONTROLLER
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Reading the EEPROM
Programming the
Fuse Low Bits
Programming the
Fuse High Bits
Programming the
Extended Fuse Bits
4250E–CAN–12/04
AT90CAN128
The algorithm for reading the EEPROM memory is as follows (refer to “Programming the
Flash” on page 331 for details on Command and Address loading):
1. A: Load Command “0000 0011”.
2. G: Load Address High Byte (0x00 - 0xFF).
3. B: Load Address Low Byte (0x00 - 0xFF).
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 “Programming
the Flash” on page 331 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. Give WR a negative pulse and wait for RDY/BSY to go high.
The algorithm for programming the Fuse High bits is as follows (refer to “Programming
the Flash” on page 331 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 “1” and BS2 to “0”. This selects high data byte.
4. Give WR a negative pulse and wait for RDY/BSY to go high.
5. Set BS1 to “0”. This selects low data byte.
The algorithm for programming the Extended Fuse bits is as follows (refer to “Program-
ming the Flash” on page 331 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 “1”. This selects extended data byte.
4. Give WR a negative pulse and wait for RDY/BSY to go high.
5. Set BS2 to “0”. This selects low data byte.
Figure 160. Programming the FUSES Waveforms
DATA
Write Fuse Low byte
A
C
0x40
DATA
XX
Write Fuse high byte
A
C
0x40
DATA
XX
XA1
XA0
BS1
BS2
XTAL1
WR
RDY/BSY
RESET +12V
OE
PAGEL
Write Extended Fuse byte
A
C
0x40
DATA
XX
335
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