M16C62N Datasheet, PDF (169/213 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

CPU Rewrite Mode (Flash Memory Version)
Mitsubishi microcomputers
M16C / 62N Group (80-pin)
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Erase All Unlock Blocks Command (A716/D016)
By writing the command code “A716” in the first bus cycle and the confirmation command code “D016”
in the second bus cycle that follows, the system starts erasing blocks successively.
Whether the erase all unlock blocks command is terminated can be confirmed by reading the status
register or the flash memory control register 0, in the same way as for block erase. Also, the status
register can be read out to know the result of the auto erase operation.
When the lock bit disable select bit of the flash memory control register 0 = 1, all blocks are erased no
matter how the lock bit is set. On the other hand, when the lock bit disable select bit = 0, the function of
the lock bit is effective and only nonlocked blocks (where lock bit data = 1) are erased.
Lock Bit Program Command (7716/D016)
By writing the command code “7716” in the first bus cycle and the confirmation command code “D016”
in the second bus cycle that follows to the block address of a flash memory block, the system sets the
lock bit for the specified block to 0 (locked). Make an address in the first bus cycle same as an address
to block by the second bus cycle.
Figure 1.29.5 shows an example of a lock bit program flowchart. The status of the lock bit (lock bit
data) can be read out by a read lock bit status command.
Whether the lock bit program command is terminated can be confirmed by reading the status register
or the flash memory control register 0, in the same way as for page program.
For details about the function of the lock bit and how to reset the lock bit, refer to the section where the
data protect function is detailed.
Start
Write 7716
Write D016
block address
Status register
read
(Set an address to even address in the user
ROM area when reading the status register)
SR7=1?
NO
or
RY/BY=1?
YES
SR4 = 0? ^NO
YES
Lock bit program
completed
Lock bit program in
error
Figure 1.29.5. Lock bit program flowchart
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