AN2156 Freescale Semiconductor / Motorola, AN2156 Datasheet - Page 35

• Manufacturer Part Number: AN2156
• Description: Programming and Erasing FLASH and EEPROM Memories on the MC68HC908AS60A/AZ60A
• Manufacturer: Freescale Semiconductor / Motorola

Selective Bit Programming
AN2156
MOTOROLA
On each programming cycle, one to eight bits of the EEPROM memory
may be programmed. It is possible to program multiple bits at the same
time. However, the same bit may not be programmed twice unless the
entire byte has been erased first. This means that the same byte location
may be programmed eight times as long as an individual bit is not written
to more than once. This is referred to as selective bit programming. The
acceptable sequence in
for eight program cycles without an erase.
EEPROM memory lifetime is guaranteed for 10-K read/write cycles.
However, using selective bit programming extends the life cycle of the
memory 8-fold since each bit is only programmed 10-K times. This
allows the user to program a single byte up to 80-K times.
If a bit is programmed more than once before the byte is erased,
Motorola cannot guarantee proper operation of the EEPROM array.
Erase
Write $FE
Write $FD
Write $FB
Write $F7
Write $EF
Write $DF
Write $BF
Write $7F
Erase
Operation
Freescale Semiconductor, Inc.
For More Information On This Product,
Acceptable Sequence
Go to: www.freescale.com
NA
1111:1110
1111:1101
1111:1011
1111:0111
1110:1111
1101:1111
1011:1111
0111:1111
NA
Program
Data
Table 6. Selective Bit Programming
Table 6
1111:1111
1111:1110
1111:1100
1111:1000
1111:0000
1110:0000
1100:0000
1000:0000
0000:0000
1111:1111
in Memory
Value
shows how the same byte may be used
Erase
Write $FE
Write $F9
Write $EF
Write $D8
Operation
Unacceptable Sequence
NA
1111:1110
1111:1001
1110:1111
1101:1000
Selective Bit Programming
Program
Data
Application Note
1111:1111
1111:1110
1111:1000
1110:1000
Unknown
in Memory
Value
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