M16C80 Datasheet, PDF (318/358 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/80 SERIES

M16C/80 Group
32. Standard serial I/O mode
Data Protection (Block Lock)
Each of the blocks in Figure 32.17 have a nonvolatile lock bit that specifies protection (block lock) against
erasing/writing. A block is locked (writing “0” for the lock bit) with the lock bit program command. Also, the
lock bit of any block can be read with the read lock bit status command.
Block lock disable/enable is determined by the status of the lock bit itself and execution status of the lock
bit disable and lock enable bit commands.
(1) After the reset has been cancelled and the lock bit enable command executed, the specified block
can be locked/unlocked using the lock bit (lock bit data). Blocks with a “0” lock bit data are locked
and cannot be erased or written in. On the other hand, blocks with a “1” lock bit data are unlocked
and can be erased or written in.
(2) After the lock bit enable command has been executed, all blocks are unlocked regardless of lock bit
data status and can be erased or written in. In this case, lock bit data that was “0” before the block
was erased is set to “1” (unlocked) after erasing, therefore the block is actually unlocked with the
lock bit.
Flash memory Flash memory
size
start address
128 Kbytes 0FE000016
256 Kbytes 0FC000016
Figure 32.17 Blocks in the user area
0FC000016
Block 6 : 64K byte
0FD000016
Block 5 : 64K byte
0FE000016
Block 4 : 64K byte
0FF000016
Block 3 : 32K byte
0FF800016
0FFA00016
0FFC00016
0FFFFFF16
Block 2 : 8K byte
Block 1 : 8K byte
Block 0 : 16K byte
User ROM area
Rev.1.00 Aug. 02, 2005 ^{Page 307} of 329
REJ09B0187-0100