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CHAPTER 21 Flash Memory
21.4 Flash Memory Auto Algorithm (Embedded Algorithm
TM
)
Writing or erasing of the flash memory cell is carried out by initiating the auto algorithm
stored by the flash memory itself.
■
Command Operation
In order to initiate the auto algorithm, execute continuous writing of half-word (16-bit) data for 1 to 6 times
to the flash memory. This is called a command.
If an invalid address or data is written, or the address and data are written in the wrong order, the flash
memory is reset to read mode.
Table 21.4-1 lists the command.
*: Commands must be issued by writing half-words under the FR-CPU programming mode.
RA: Read address /RD: Read data
PA: Write address/PD: Write data
SA: Sector address (specification of any address in the sector. Refer to Table 21.1-1 and Table 21.1-2 )
Erase suspension command (B0
H
) and erase restart command (30
H
) are only valid while erasing the sector.
Two types of reset command can reset the flash memory to read mode.
Table 21.4-1 Command sequence table
Command
sequence
Access numbers
1 Writing Cycle 2 Writing Cycle 3 Writing Cycle 4 Writing Cycle 5 Writing Cycle 6 Writing Cycle
Address Data Address Data Address Data Address Data Address Data Address Data
Read/Reset 1
XXXXXXXX
H
F0F0
H
---- -
Read/Reset 4
000F5556
H
AAAA
H
000EAAAA
H
5555
H
000F5556
H
F0F0
H
RA RD - -
Program 4
000F5556
H
AAAA
H
000EAAAA
H
5555
H
000F5556
H
A0A0
H
PA PD
000EAAAA
H
5555
H
000E5556H
1010
H
Chip Erasing 6
000F5556
H
AAAA
H
000EAAAA
H
5555
H
000F5556
H
8080
H
000F5556
H
AAAA
H
000EAAAA
H
5555
H
SA
3030
H
Sector Erasing 6
000F5556
H
AAAA
H
000EAAAA
H
5555
H
000F5556
H
8080
H
000F5556
H
AAAA
H
--
Sector Erasing being Suspended
XXXXXXXX
H
B0B0
H
---- -
Sector Erasing being Restarted
XXXXXXXX
H
3030
H
---- -