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Why some registers can't be rewritten after programming flash memory?

Latest Updated:05/27/2013

Question:

After programming or erasing the flash memory, some registers (clock generation circuit and low power consumption function) cannot be rewritten.

Answer:

The following registers cannot be rewritten in ROM P/E mode or E2 DataFlash P/E mode. Switch to ROM read mode to rewrite.

- System clock control register (SCKCR)
- System clock control register 2 (SCKCR2)
- System clock control register 3 (SCKCR3)
- External bus clock control register (BCKCR)
- Operating power control register (OPCCR)

For details, please refer to the respective register descriptions in the user's manual: hardware.

Suitable Products
RX630
RX63N, RX631
RX210
RX220
RX110
RX111