R28 datasheet(365/473 Pages) RENESAS

365 / 473 page

R8C/28 Group, R8C/29 Group

19. Flash Memory

Rev.2.10

Sep 26, 2008

Page 346 of 441

REJ09B0279-0210

19.4.1

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.

During auto-erasure, set the FMR40 bit to 1 (erase-suspend enabled) and the FMR41 bit to 1 (request erase-

suspend). Wait for td(SR-SUS) and ensure that the FMR46 bit is set to 1 (read enabled) before accessing the

user ROM area. The auto-erase operation can be restarted by setting the FMR41 bit to 0 (erase restarts).

To enter program-suspend during the auto-program operation, set the FMR40 bit to 1 (suspend enabled) and the

FMR42 bit to 1 (request program-suspend). Wait for td(SR-SUS) and ensure that the FMR46 bit is set to 1 (read

enabled) before accessing the user ROM area. The auto-program operation can be restarted by setting the

FMR42 bit to 0 (program restarts).

19.4.2

EW1 Mode

The MCU is switched to EW1 mode by setting the FMR11 bit to 1 (EW1 mode) after setting the FMR01 bit to

1 (CPU rewrite mode enabled).

The FMR0 register can be used to determine when program and erase operations complete. Do not execute

commands that use the read status register in EW1 mode.

To enable the erase-suspend function during auto-erasure, execute the block erase command after setting the

FMR40 bit to 1 (erase-suspend enabled). The interrupt to enter erase-suspend should be in interrupt enabled

status. After waiting for td(SR-SUS) after the block erase command is executed, the interrupt request is

acknowledged.

When an interrupt request is generated, the FMR41 bit is automatically set to 1 (requests erase-suspend) and the

auto-erase operation suspends. If an auto-erase operation does not complete (FMR00 bit is 0) after an interrupt

process completes, the auto-erase operation restarts by setting the FMR41 bit to 0 (erasure restarts)

To enable the program-suspend function during auto-programming, execute the program command after setting

the FMR40 bit to 1 (suspend enabled). The interrupt to enter program-suspend should be in interrupt enabled

status. After waiting for td(SR-SUS) after the program command is executed, an interrupt request is

acknowledged.

When an interrupt request is generated, the FMR42 bit is automatically set to 1 (request program-suspend) and

the auto-program operation suspends. When the auto-program operation does not complete (FMR00 bit is 0)

after the interrupt process completes, the auto-program operation can be restarted by setting the FMR42 bit to 0

(programming restarts).

R28 Datasheet(PDF) 365 Page - Renesas Technology Corp