R8C2K Datasheet, PDF (391/471 Pages) Renesas Technology Corp – MCU

R8C/2K Group, R8C/2L Group
20. Flash Memory
20.4.3 EW0 Mode
The MCU enters CPU rewrite mode and software commands can be acknowledged by setting the FMR01 bit in
the FMR0 register to 1 (CPU rewrite mode enabled). In this case, since the FMR11 bit in the FMR1 register is
set to 0, EW0 mode is selected.
Use software commands to control program and erase operations. The FMR0 register or the status register can
be used to determine when program and erase operations complete.
Figure 20.8 shows the How to Set and Exit EW0 Mode.
EW0 Mode Operating Procedure
Set registers⁽¹⁾ CM0 and CM1
Transfer a rewrite control program which uses CPU
rewrite mode to the RAM.
Jump to the rewrite control program which has been
transferred to the RAM.
(The subsequent process is executed by the rewrite
control program in the RAM.)
Rewrite control program
Write 0 to the FMR01 bit before writing 1
(CPU rewrite mode enabled)⁽²⁾
Execute software commands
Execute the read array command⁽³⁾
Write 0 to the FMR01 bit
(CPU rewrite mode disabled)
Jump to a specified address in the flash memory
NOTES:
1. Select 5 MHz or below for the CPU clock by the CM06 bit in the CM0 register and bits CM16 to CM17 in the CM1 register.
2. To set the FMR01 bit to 1, write 0 to the FMR01 bit before writing 1. Do not generate an interrupt between writing 0 and 1.
Write to the FMR01 bit in the RAM.
3. Disable the CPU rewrite mode after executing the read array command.
Figure 20.8 How to Set and Exit EW0 Mode
Rev.1.10 Dec 21, 2007 Page 374 of 450
REJ09B0406-0110