R8C/13 Group
19. Usage Notes
19.7 Flash Memory Version
19.7.1 CPU Rewrite Mode
ꢀꢀOperation Speed
Before entering CPU rewrite mode (EW0 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. This usage note is not
needed for EW1 mode.
ꢀꢀ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 page 195 of 205
REJ09B0111-0120
RENESAS [ RENESAS TECHNOLOGY CORP ]
