
R8C/38T-A Group
26. Flash Memory
Under development Preliminary document
Specifications in this document are tentative and subject to change.
R01UH0241EJ0010 Rev.0.10
Page 637 of 730
Aug 05, 2011
When the FMR22 bit is set to 1 (erase-suspend request enabled by interrupt request), the FMR21 bit is
automatically set to 1 (erase-suspend request) when an interrupt request is generated during auto-erasure.
Set the FMR22 bit to 1 when using erase-suspend while rewriting the user ROM area in EW1 mode.
When the FMR24 bit is 0, one wait cycle is required for program ROM and three wait cycles are required for
data flash.
When the FMR24 bit is 1, zero wait cycle is required for program ROM and one wait cycle is required for data
flash.
When the FMR27 bit is set to 1 (low-current-consumption read mode enabled) in low-speed clock mode (XIN
clock stopped) or low-speed on-chip oscillator mode (XIN clock stopped), power consumption when reading
Low-current-consumption read mode can be used when the CPU clock is set to the low-speed on-chip oscillator
clock divided by 4, 8, or 16. Do not use low-current-consumption read mode when the clock is divided by 1 (no
division) or 2. After setting the division ratio of the CPU clock, set the FMR27 bit to 1.
When entering wait mode or stop mode while the FMR27 bit is 1 (low-current-consumption read mode
enabled), set bits CM37 and CM36 in the CM3 register to 00b (MCU exits using the CPU clock used
immediately before entering wait or stop mode), and the CM35 bit to 0 (settings of CM06 bit in CM0 register
and bits CM16 and CM17 in CM1 register enabled).
When the FMR27 bit is 1 (low-current-consumption read mode enabled), do not execute any program, block
erase, or lock bit program commands. To change the FMSTP bit from 1 (flash memory stops) to 0 (flash
memory operates), make the setting when the FMR27 bit is 0 (low-current-consumption read mode disabled).