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M16C/5L Group, M16C/56 Group
7.3
Optional Function Select Area
In the optional function select area, the MCU state after reset and the function to prevent rewrite in parallel
I/O mode are selected.
The optional function select area is not an SFR, and therefore cannot be rewritten by a program. Set an
appropriate value when writing a program to flash memory. The entire optional function select area
becomes FFh when the block including the optional function select area is erased.
In blank products, the OFS1 address value is FFh when shipped. After a value is written by the user, this
address takes on the written value.
In programmed products, the OFS1 address value is the value set in the user program prior to shipping.
7.3.1
Optional Function Select Address 1 (OFS1)
Optional Function Select Address 1
b7
b6 b5 b4
b3
b2
b1
0
1
1
LVDAS (Voltage detector 0 start bit) (b6)
When using power-on reset, set this bit to 0 (voltage monitor 0 reset enabled after hardware reset).
This bit is enabled in single-chip mode, while disabled in boot mode.
R01UH0127EJ0110 Rev.1.10
Sep 01, 2011
Symbol
b0
OFS1
Bit Symbol
Bit Name
WDTON
Watchdog timer start select bit
—
Reserved bit
(b1)
ROMCR
ROM code protect cancel bit
ROMCP1 ROM code protect bit
—
Reserved bit
(b4)
—
Reserved bit
(b5)
LVDAS
Voltage detector 0 start bit
After-reset count source
CSPROINI
protection mode select bit
Address
FFFFFh
Function
0 : Watchdog timer starts automatically
after reset.
1 : Watchdog timer is in a stopped state
after reset.
Set to 1.
0 : ROM code protection cancelled.
1 : ROMCP1 bit enabled.
0 : ROM code protection enabled.
1 : ROM code protection cancelled.
Set to 1.
Set to 0.
0 : Voltage monitor 0 reset enabled
after hardware reset.
1 : Voltage monitor 0 reset disabled
after hardware reset.
0 : Count source protection mode
enabled after reset.
1 : Count source protection mode
disabled after reset.
7. Voltage Detector
Page 82 of 803
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