AT90S4414/8515
74
Reading the Flash
The algorithm for reading the Flash memory is as follows (refer to Programming the Flash for details on Command and
Address loading):
1. A: Load Command “0000 0010”.
2. B: Load Address High Byte ($00 - $07/$0F).
3. C: Load Address Low Byte ($00 - $FF).
4. Set OE
to “0”, and BS to “0”. The Flash word low byte can now be read at DATA.
5. Set BS to “1”. The Flash word high byte can now be read from DATA.
6. Set OE
to “1”.
Programming the EEPROM
The programming algorithm for the EEPROM data memory is as follows (refer to Programming the Flash for details on
Command, Address and Data loading):
1. A: Load Command “0001 0001”.
2. (AT90S8515 only) B: Load Address High Byte ($00 - $01)
3. C: Load Address Low Byte ($00 - $FF).
4. D: Load Data Low Byte ($00 - $FF).
5. E: Write Data Low Byte.
Reading the EEPROM
The algorithm for reading the EEPROM memory is as follows (refer to Programming the Flash for details on Command and
Address loading):
1. A: Load Command “0000 0011”.
2. (AT90S8515 only) B: Load Address High Byte ($00 - $01)
3. C: Load Address Low Byte ($00 - $FF).
4. Set OE
to “0”, and BS to “0”. The EEPROM data byte can now be read at DATA.
5. Set OE
to “1”.
Programming the Fuse Bits
The algorithm for programming the Fuse bits is as follows (refer to Programming the Flash for details on Command and
Data loading):
1. A: Load Command “0100 0000”.
2. D: Load Data Low Byte. Bit n = ‘0’ programs and bit n = “1” erases the Fuse bit.
Bit 5 = SPIEN Fuse bit.
Bit 0 = FSTRT Fuse bit.
Bit 7-6,4-1 = “1”. These bits are reserved and should be left unprogrammed (“1”).
3. Give WR
a t
WLWH_PFB
wide negative pulse to execute the programming, t
WLWH_PFB
is found in Table 31. Programming
the Fuse bits does not generate any activity on the RDY/BSY
pin.
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