R8C2K datasheet(391/471 Pages) RENESAS

391 / 471 page

R8C/2K Group, R8C/2L Group

20. Flash Memory

Rev.1.10

Dec 21, 2007

Page 374 of 450

REJ09B0406-0110

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.

Figure 20.8

How to Set and Exit EW0 Mode

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.)

Write 0 to the FMR01 bit before writing 1

(CPU rewrite mode enabled)(2)

Execute the read array command(3)

Execute software commands

Write 0 to the FMR01 bit

(CPU rewrite mode disabled)

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 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.

EW0 Mode Operating Procedure

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