M16C30P_07 Datasheet, PDF (233/317 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/30 SERIES

M16C/30P Group
19. Flash Memory Version
19.3.6 Data Protect Function
Each block in the flash memory has a nonvolatile lock bit. The lock bit is enabled by setting the FMR02 bit to
“0” (lock bit enabled). The lock bit allows each block to be individually protected (locked) against program and
erase. This helps prevent data from being inadvertently written to or erased from the flash memory.
• When the lock bit status is set to “0”, the block is locked (block is protected against program and erase).
• When the lock bit status is set to “1”, the block is not locked (block can be programmed or erased).
The lock bit status is set to “0” (locked) by executing the lock bit program command and to “1” (unlocked) by
erasing the block. The lock bit status cannot be set to “1” by any commands.
The lock bit status can be read by the read lock bit status command.
The lock bit function is disabled by setting the FMR02 bit to “1”. All blocks are unlocked. However, individual
lock bit status remains unchanged. The lock bit function is enabled by setting the FMR02 bit to “0”. Lock bit
status is retained.
If the block erase command is executed while the FMR02 bit is set to “1”, the target block is erased regardless
of lock bit status. The lock bit status of each block are set to “1” after an erase operation is completed.
Refer to 19.3.5 Software Commands for details on each command.
19.3.7 Status Register
The status register indicates the flash memory operation state and whether or not an erase or program operation
is completed as expected. The FMR00, FMR06 and FMR07 bits in the FMR0 register indicate status register
states.
Table 19.7 shows the Status Register.
In EW0 mode, the status register can be read when the followings occur.
• Any even address in the user ROM area is read after writing the read status register command.
• Any even address in the user ROM area is read from when the program, block erase, or lock bit program
command is executed until when the read array command is executed.
19.3.7.1 Sequence Status (SR7 and FMR00 Bits)
The sequence status indicates the flash memory operation state. It is set to “0” while the program, block erase,
lock bit program, or read lock bit status command is being executed; otherwise, it is set to “1”.
19.3.7.2 Erase Status (SR5 and FMR07 Bits)
Refer to 19.3.8 Full Status Check.
19.3.7.3 Program Status (SR4 and FMR06 Bits)
Refer to 19.3.8 Full Status Check.
Rev.1.22 Mar 29, 2007 Page 217 of 291
REJ09B0179-0122