R8C13 datasheet(55/224 Pages) RENESAS

55 / 224 page

Rev.1.20

Jan 27, 2006

page 44 of 205

REJ09B0111-0120

R8C/13 Group

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, HR0, HR1 registers

• Registers protected by PRC1 bit: PM0 and PM1 registers

• Registers protected by PRC2 bit: PD0 register

• Registers protected by PRC3 bit: VCR2 and D4INT registers

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,PRC1 and PRC3 bsits 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

7. Protection

Protect register

Symbol

Address

After reset

PRCR

000A16

00XXX0002

Bit name

Bit symbol

b6b5b4b3

b2b1b0

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,

HR0, HR1 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 bitWhen write, should set to “0”

(b5-b4)

Reserved bit

PRC2

Protect bit 3

0 : Write protected

1 : Write enabled

Enable write to VCR2, D4INT

registers

PRC3

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