M16CSLASH29 datasheet(362/499 Pages) RENESAS

362 / 499 page

20. Flash Memory Version

page 338

20.4.1 EW Mode 0

The MCU enters CPU rewrite mode by setting the FMR01 bit in the FMR0 register to 1 (CPU rewrite mode

enabled) and is ready to accept software commands. EW mode 0 is selected by setting the FMR11 bit in

the FMR1 register to 0.

To set the FMR01 bit to 1, set to 1 after first writing 0. The software commands control programming and

erasing. The FMR0 register or the status register indicates whether a programming or erasing operations

is completed.

When entering the erase-suspend during the auto-erasing, set the FMR40 bit to 1 (erase-suspend en-

abled) and the FMR41 bit to 1 (suspend request). After waiting for td(SR-ES) and verifying the FMR46 bit

is set to 1 (auto-erase stop), access to the user ROM area. When setting the FMR41 bit to 0 (erase

restart), auto-erasing is restarted.

20.4.2 EW Mode 1

EW mode 1 is selected by setting the FMR11 bit to 1 after the FMR01 bit is set to 1 (set to 1 after first

writing 0).

The FMR0 register indicates whether or not a programming or an erasing operation is completed. Read

status register cannot be read in EW mode 1.

When an erase/program command is initiated, the CPU halts all program execution until the command

operation is completed or erase-suspend request is generated.

When enabling an erase-suspend function, set the FMR40 bit to 1 (erase suspend enabled) and execute

block erase commands. Also, the interrupt to transfer to erase-suspend must be set enabled preliminar-

ily. When entering erase-suspend after td(SR-ES) from an interrupt is requested, interrupts can be ac-

cepted.

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

auto-erasing is suspended. If an auto-erasing has not completed (when the FMR00 bit is 0) after an

interrupt process is completed, set the FMR41 bit to 0 (erase restart) and execute block erase commands

again.

M16C/29 датащи(PDF) 362 Page - Renesas Technology Corp