R8C datasheet(40/199 Pages) RENESAS

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R8C/10 Group

7. Protection

Rev.1.20 Jan 27, 2006

page 30 of 180

REJ09B0019-0120

7. Protection

In the event that a program runs out of control, this function protects the important registers so that they

will not be rewritten easily. Figure 7.1 shows the PRCR register. The following lists the registers protected

by the PRCR register.

• Registers protected by PRC0 bit: CM0, CM1, and OCD registers

• Registers protected by PRC1 bit: PM0 and PM1 registers

• Registers protected by PRC2 bit: PD0 register

Set the PRC2 bit to “1” (write enabled) and then write to any address, and the PRC2 bit will be set to “0”

(write protected). The registers protected by the PRC2 bit should be changed in the next instruction after

setting the PRC2 bit to “1”. Make sure no interrupts will occur between the instruction in which the PRC2

bit is set to “1” and the next instruction. The PRC0 and PRC1 bits are not automatically set to “0” by writing

to any address. They can only be set to “0” in a program.

Figure 7.1 PRCR Register

Protect register

Symbol

Address

After reset

PRCR

000A16

00XXX0002

Bit name

Bit symbol

0 : Write protected

1 : Write enabled

PRC1

PRC0

Function

NOTES:

1. The PRC2 bit is set to “0” by writing to any address after setting it to “1”. Other bits are not set to “0”

by writing to any address, and must therefore be set to “0” in a program.

Protect bit 0

Protect bit 1

Protect bit 2

Enable write to CM0, CM1, OCD

registers

0 : Write protected

1 : Write enabled

Enable write to PM0, PM1

registers

0 : Write protected

1 : Write enabled1

Enable write to PD0 register

When read, its content is “0”.

(b7-b6)

Reserved bit

When write, must set to "0"

(b5-b3)

Reserved bit

PRC2

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