
25. Flash Memory
25.3
CPU Rewrite Mode
In CPU rewrite mode, the user ROM area can be rewritten when the CPU executes software commands. The user
ROM area can be rewritten when the MCU is mounted on a board without using a parallel or serial programmer.
In CPU rewrite mode, only the user ROM area shown in
Figure 25.1 can be rewritten. The boot ROM area cannot
be rewritten. Execute the program and block erase commands only on the blocks in the user ROM area.
Table 25.3 lists specifications in CPU rewrite mode. Figure 25.7 shows a setting procedure in CPU rewrite mode.
Table 25.3
Specifications in CPU Rewrite Mode
When the FMR01 bit in the FMR0 register is set to 1 (CPU rewrite mode enabled), CPU rewrite mode is
entered and commands can be acknowledged. To set the FMR01 bit to 1, write a 1 immediately after writing a
0.
Software commands control program and erase operations. Whether a program or erase operation is completed
successfully or not can be checked by reading the FMR0 register or executing the read status register command.
Item
Specification
Operating mode
Single-chip mode
Boot mode
Areas where a rewrite
program can be stored
User ROM area (Single-chip mode)
Boot ROM area (Boot mode)
Areas where a rewrite
control program can be
placed to execute
Rewrite control program must be transferred to a given area other than the flash
memory (e.g.,RAM) before executing
Areas which can be
rewritten
User ROM area
Mode after program or
erase
Read status register mode
CPU status during auto-
program and auto-erase
Operating
Flash memory status
detection
Read bits FMR00, FMR06, and FMR07 in the FMR0 register by program
Execute the read status register command to read bits SR7, SR5, and SR4 in the
SRD register