R8C/20 Group, R8C/21 Group 19. Flash Memory
Rev.2.00 Aug 27, 2008 Page 390 of 458
REJ09B0250-0200
Figure 19.9 shows the How to Set and Exit EW0 Mode. Figure 19.10 shows the How to Set and Exit EW1
Mode.
Figure 19.9 How to Set and Exit EW0 Mode
Figure 19.10 How to Set and Exit EW1 Mode
Set CM0 and CM1 registers
(1)
Set the FMR01 bit by writing 0 and then 1
(CPU rewrite mode enabled)
(2)
Execute the read array command
(3)
Execute software commands
Write 0 to the FMR01 bit
(CPU rewrite mode enabled)
Jump to a specified address in the flash memory
Rewrite control program
NOTES:
1. Select 5 MHz or below for the CPU clock by the CM06 bit in the CM0 register and the CM16 to CM17 bits in the CM1 register.
2. When setting 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.
EW0 Mode Operating Procedure
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.)
Write 0 to the FMR01 bit before writing 0
(CPU rewrite mode enabled)
(1)
Write 0 to the FMR11 bit before writing 1
(EW1 mode)
Execute software commands
Write 0 to the FMR01 bit
(CPU rewrite mode disabled)
NOTE:
1. When setting the FMR01 bit to 1, write 0 to the FMR01 bit before writing 1.
Do not generate an interrupt between writing 0 and 1.
EW1 Mode Operating Procedure
Program in ROM
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