Flash Memory Version - Renesas M16C Series Hardware Manual

R8C/11 Group

19.7 Flash Memory Version

19.7.1 CPU Rewrite Mode
Operation Speed
Before entering CPU rewrite mode (EW0 mode, EW1 mode), select 5MHz or below for the CPU clock
using the CM06 bit in the CM0 register and the CM16 to CM17 bits in the CM1 register.
Instructions Diabled Against Use
The following instructions cannot be used in EW0 mode because the flash memory internal data is
referenced: UND, INTO and BRK instructions.
How to Access
Write "0" to the corresponding bits before writing "1" when setting the FMR01, FMR02, and FMR11
bits to "1". Do not generate an interrupt between writing "0" and "1".
Rewriting User ROM Area
In EW0 mode, if the power supply voltage drops while rewriting any block in which the rewrite control
program is stored, the flash memory may not be able to be rewritten because the rewrite control
program cannot be rewritten correctly. In this case, use stnadard serial I/O mode.
Reset Flash Memory
Since the CPU stops and cannot return when setting the FMSTP bit in the FMR0 register to "1" (flash
memory stops) during erase suspend in EW1 mode, do not set the FMSTP bit to "1".
Entering Stop Mode or Wait Mode
Do not enter stop mode or wait mode during erase-suspend.
Rev.1.20 Jan 27, 2006
REJ09B0062-0120
page 194 of 204
19. Usage Notes