M16C Datasheet, PDF (222/262 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

Preliminary Specifications REV.B
Mitsubishi microcomputers
Specifications in this manual are tentative and subject to change.
M16C / 6N Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
CPU Rewrite Mode
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 or not the erase all unlock blocks command is terminated can be confirmed by reading the
status register or the flash memory control register, 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 bit of the flash memory control register is 1, all blocks are erased no matter
how the lock bit is set. On the other hand, when the lock bit disable bit is 0, the function of the lock bit
is effective and only nonlocked blocks (when lock bit data is 1) are erased.
Lock Bit Program Command (7716/D016)
By writing the command code "7716" in the first bus cycle, the confirmation command code "D016" and
the block address of a flash memory block in the second bus cycle that follows, the system sets the
lock bit for the specified block to 0 (locked).
Figure 23-5 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 or not the lock bit program command is terminated can be confirmed by reading the status
register or the flash memory control register, 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
NO
SR7 = 1?
YES
NO
SR4 = 0?
YES
Lock bit program
completed
Lock bit program in
error
Figure 23-6. Lock bit program flowchart
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