m5m51016btp Renesas Electronics Corporation., m5m51016btp Datasheet - Page 13

• Manufacturer Part Number: m5m51016btp
• Description: Renesas 16-bit Single-chip Microcomputer M16c Family / M16c/20 Series
• Manufacturer: Renesas Electronics Corporation.

M30245 Group
Rev.2.00 Oct 16, 2006
REJ09B0340-0200
2.1 Protect
Figure 2.1.1. Protect register
2.1.1 Overview
'Protect' is a function that causes a value held in a register to be unchanged even when a program runs
away. The following is an overview of the protect function:
(1) Registers affected by the protect function
(2) Protect register
Protect register
b7 b6 b5 b4 b3 b2 b1 b0
The registers affected by the protect function are:
The values in registers (a) through (c) cannot be changed in write-protect state. To change values in
the registers, put the individual registers in write-enabled state.
Figure 2.1.1 shows protect register.
(a) System clock control registers 0, 1 (addresses 0006
(b) Processor mode registers 0, 1 (addresses 0004
(c) Frequency synthesizer-related registers (address 03DB
0
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Bit symbol
Nothing is assigned.
When write, set “0”. When read, their contents are indeterminate.
PRC0
Reserved
PRC1
Symbol
PRCR
Enables writing to system clock
control registers 0 and 1 (addresses
0006
synthesizer registers (addresses
03DB
Enables writing to processor mode
registers 0 and 1 (addresses 0004
and 0005
16
16
and 0007
to 03DF
16
)
Address
000A
Bit name
16
16
)
16
) and frequency
16
XXXXX000
When reset
and 0005
16
and 0007
16
16
to 03DF
16
2
0 : Write-inhibited
1 : Write-enabled
0 : Write-inhibited
1 : Write-enabled
Must always be set to “0”
)
16
)
16
Function
)
R
2. Protect
W