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CHAPTER 19 FLASH MEMORY
19.4
Automatic Algorithm of Flash Memory
The flash memory automatic algorithm can be started using a Read/Reset, Write, Chip
Erase, or Sector Erase command. The Sector Erase command can stop and restart the
automatic algorithm.
■ Command Sequence
At the start of the automatic algorithm, one to six half-words (16 bits) are written. This data is
called the command.
If the address and data to be written are invalid or are written in an incorrect sequence, the flash
memory is reset to read mode.
Table 19.4-1 lists commands that can be used to write data to or erase data from flash memory.
Table 19.4-1 Command Sequence (MB91FV319A, MB91F318A)
First bus write
Bus
Command
cycle
write
sequence
cycle
FMA
Read/Reset
1
AXXXX
Read/Reset
4
AAAAA
Write
4
AAAAA
Chip Erase
6
AAAAA
Sector Erase
6
AAAAA
Table 19.4-2 Command Sequence (MB91F318S, MB91FV319R)
First bus write
Bus
Command
cycle
write
sequence
cycle
FMA
Read/Reset
1
AXXXX
Read/Reset
4
A5557
Write
4
A5557
Chip Erase
6
A5557
Sector Erase
6
A5557
RA: Flash memory read address
PA: Flash memory write address
SA: Address of sector to be erased in flash memory (Specify an address in a sector.)
RD: Data read from flash memory
FMA: Address
DIN: Written data
644
Second bus write
cycle
DIN
FMA
DIN
F0F0
---
---
H
H
AAAA
A5555
5555
H
H
H
H
AAAA
A5555
5555
H
H
H
H
AAAA
A5555
5555
H
H
H
H
AAAA
A5555
5555
H
H
H
H
Second bus write
cycle
DIN
FMA
DIN
F0F0
---
---
H
H
AAAA
AAAAB
5555
H
H
H
H
AAAA
AAAAB
5555
H
H
H
H
AAAA
AAAAB
5555
H
H
H
H
AAAA
AAAAB
5555
H
H
H
H
Third bus write
Fourth bus write
cycle
cycle
FMA
DIN
FMA
----
---
---
AAAAA
F0F0
RA
H
H
AAAAA
A0A0
PA
H
H
AAAAA
8080
AAAAA
H
H
H
AAAAA
8080
AAAAA
H
H
H
Third bus write
Fourth bus write
cycle
cycle
FMA
DIN
FMA
----
---
---
A5557
F0F0
RA
H
H
A5557
A0A0
PA
H
H
A5557
8080
A5557
H
H
H
A5557
8080
A5557
H
H
H
Fifth bus write
cycle
DIN
FMA
DIN
---
---
---
RD
---
---
PD
---
---
AAAA
A5555
5555
AAAAA
H
H
H
AAAA
A5555
5555
H
H
H
Fifth bus write
cycle
DIN
FMA
DIN
---
---
---
RD
---
---
PD
---
---
AAAA
AAAAB
5555
A5557
H
H
H
AAAA
AAAAB
5555
H
H
H
Sixth bus write
cycle
FMA
DIN
---
---
---
---
---
---
1010
H
H
SA
3030
H
Sixth bus write
cycle
FMA
DIN
---
---
---
---
---
---
1010
H
H
SA
3030
H
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