R5F21133DFP RENESAS [Renesas Technology Corp], R5F21133DFP Datasheet - Page 55

• Manufacturer Part Number: R5F21133DFP
• Description: 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY/R8C/Tiny SERIES
• Manufacturer: RENESAS [Renesas Technology Corp]

R8C/13 Group
Rev.1.20
REJ09B0111-0120
7. Protection
Figure 7.1 PRCR Register
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.
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.
• 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
P r o t e c t r e g i s t e r
b 7
N O T E S :
1 . T h e P R C 2 b i t i s s e t t o “ 0 ” b y w r i t i n g t o a n y a d d r e s s a f t e r s e t t i n g i t t o “ 1 ” . O t h e r b i t s a r e n o t s e t t o “ 0 ”
Jan 27, 2006
b 6
b y w r i t i n g t o a n y a d d r e s s , a n d m u s t t h e r e f o r e b e s e t t o “ 0 ” i n a p r o g r a m .
b 5
0
b 4
0
b 3
b 2
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b 1
b 0
Bit symbol
( b 7 - b 6 )
( b 5 - b 4 )
PRC0
P R C 1
PRC2
PRC3
Symbol
PRCR
R e s e r v e d b i t
R e s e r v e d b i t
Protect bit 0
P r o t e c t b i t 1
Protect bit 2
Protect bit 3
Bit name
Address
000A
16
00XXX000
After reset
W h e n w r i t e , s h o u l d s e t t o “ 0 ”
When read, its content is “0”.
Enable write to CM0, CM1, OCD,
HR0, HR1 registers
0 : Write protected
1 : Write enabled
E n a b l e w r i t e t o P M 0 , P M 1
r e g i s t e r s
0 : Write protected
1 : Write enabled
Enable write to PD0 register
0 : Write protected
1 : Write enabled
Enable write to VCR2, D4INT
registers
0 : W r i t e p r o t e c t e d
1 : W r i t e e n a b l e d
2
Function
1
7. Protection
RW
RW
RW
RW
R W
R W
R O