M16C65 Datasheet, PDF (91/829 Pages) Renesas Technology Corp – RENESAS MCU M16C FAMILY / M16C/60

Under development
M16C/65 Group
Preliminary Specification
This is a preliminary specification and is subject to change.
5. Protection
PRC6, PRC3, PRC1, PRC0 (Protect Bits 6, 3, 1, 0) (b6, b3, b1, b0)
When setting bits PRC6, PRC3, PRC1, and PRC0 to 1 (write enabled) by a program, the bits remain 1
(write enabled). To change registers protected by these bits, follow the procedures below:
(1) Set the PRCi (i = 0, 1, 3, 6) to 1.
(2) Write to the register protected by the PRCi bit.
(3) Set the PRCi bit to 0 (write protected).
PRC2 (Protect Bit 2) (b2)
After setting the PRC2 bit to 1 (write enabled), by writing to a given SFR, the PRC2 bit becomes 0.
Change the registers protected by the PRC2 bit in the next instruction after setting the PRC2 bit to 1.
The procedure is shown below. Make sure there are no interrupts or DMA transfers between procedure
1 and 2.
(1) Set the PRC2 bit to 1.
(2) Write to the register protected by the PRC2 bit.
REJ09B0484-0030 Rev.0.30 Sep 09, 2008
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