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R8C/38T-A Group
8. Watchdog Timer
Under development Preliminary document
Specifications in this document are tentative and subject to change.
R01UH0241EJ0010 Rev.0.10
Page 81 of 730
Aug 05, 2011
8.2.7
Option Function Select Register (OFS)
Notes:
1. The OFS register is allocated in the flash memory, not in the SFRs. Set appropriate values as ROM data by a
program. Do not perform any additional writes to the OFS register. Erasing the block including the OFS register
sets the OFS register to FFh. The value of the OFS register is FFh at shipment of blank products. After
programming, the value is the same as that programmed by the user. At shipment of factory-programmed
products, the value of the OFS register is the same as that set in a program by the user.
2. The same voltage detection 0 level selected by bits VDSEL0 and VDSEL1 is set in both the voltage monitor 0
reset and power-on reset functions.
3. Set the LVDAS bit to 0 (voltage monitor 0 reset enabled after reset) to use the power-on reset or voltage monitor
0 reset.
For an example of the OFS register settings, refer to 5.6.1 Option Function Select Area Setting Examples.
LVDAS Bit (Voltage detection 0 circuit start bit)
The Vdet0 voltage monitored in the voltage detection 0 circuit is selected by bits VDSEL0 and VDSEL1.
Address 0FFFFh
Bit
b7
b6b5b4
b3b2b1
b0
Symbol CSPROINI
LVDAS
VDSEL1 VDSEL0 ROMCP1 ROMCR
—
WDTON
After Reset
User Setting Value (1)
Bit
Symbol
Bit Name
Function
R/W
b0
WDTON
Watchdog timer start select bit 0: Watchdog timer automatically starts after reset
1: Watchdog timer is stopped after reset
R/W
b1
—
Reserved
Set to 1.
R/W
b2
ROMCR
ROM code protect disable bit
0: ROM code protect disabled
1: ROMCP1 bit enabled
R/W
b3
ROMCP1
ROM code protect bit
0: ROM code protect enabled
1: ROM code protect disabled
R/W
b4
VDSEL0
Voltage detection 0 level
select bits
b5 b4
0 0: 3.80 V (typ.) selected (Vdet0_3)
0 1: 2.85 V (typ.) selected (Vdet0_2)
1 0: 2.35 V (typ.) selected (Vdet0_1)
1 1: 1.90 V (typ.) selected (Vdet0_0)
R/W
b5
VDSEL1
R/W
b6
LVDAS
Voltage detection 0 circuit
start bit
0: Voltage monitor 0 reset enabled after reset
1: Voltage monitor 0 reset disabled after reset
R/W
b7
CSPROINI Count source protection mode
after reset select bit
0: Count source protect mode enabled after reset
1: Count source protect mode disabled after reset
R/W