
R8C/2C Group, R8C/2D Group
6. Voltage Detection Circuit
Rev.2.00
Dec 05, 2007
REJ09B0339-0200
Figure 6.5
Registers VCA1 and VCA2
Voltage Detection Register 1
Symbol
Address
After Reset(2)
VCA1
0031h
00001000b
Bit Symbol
Bit Name
Function
RW
NOTES:
1.
2. The softw are reset, w atchdog timer reset, voltage monitor 1 reset, and voltage monitor 2 reset do not affect this
register.
VCA13
Voltage detection 2 signal monitor
flag(1)
00
—
(b2-b0)
RW
0 : VCC < Vdet2
1 : VCC ≥ Vdet2 or voltage detection 2
circuit disabled
RO
Reserved bits
b0
0000
Set to 0.
0
b7 b6 b5 b4 b3 b2 b1
The VCA13 bit is enabled w hen the VCA27 bit in the VCA2 register is set to 1 (voltage detection 2 circuit enabled).
The VCA13 bit is set to 1 (VCC ≥ Vdet 2) w hen the VCA27 bit in the VCA2 register is set to 0 (voltage detection 2
circuit disabled).
—
(b7-b4)
Reserved bits
Set to 0.
RW
Voltage Detection Register 2(1)
Symbol
Address
After Reset(5)
VCA2
0032h
Bit Symbol
Bit Name
Function
RW
NOTES:
1.
2.
3.
4.
5.
6. Use the VCA20 bit only w hen entering to w ait mode. To set the VCA20 bit, follow the procedure show n in Figure
10.10 Procedure for Enabling Reduced Internal Pow er Consum ption Using VCA20 bit.
VCA20
Internal pow er low
consumption enable bit(6)
0 : Disables low consumption
1 : Enables low consumption
RW
Set the PRC3 bit in the PRCR register to 1 (w rite enable) before w riting to the VCA2 register.
To use the voltage monitor 1 interrupt/reset or the VW1C3 bit in the VW1C register, set the VCA26 bit to 1.
After the VCA26 bit is set to 1 from 0, the voltage detection circuit w aits for td(E-A) to elapse before starting
operation.
To use the voltage monitor 2 interrupt/reset or the VCA13 bit in the VCA1 register, set the VCA27 bit to 1.
After the VCA27 bit is set to 1 from 0, the voltage detection circuit w aits for td(E-A) to elapse before starting
operation.
Softw are reset, w atchdog timer reset, voltage monitor 1 reset, and voltage monitor 2 reset do not affect this
register.
To use the voltage monitor 0 reset, set the VCA25 bit to 1.
After the VCA25 bit is set to 1 from 0, the voltage detection circuit w aits for td(E-A) to elapse before starting
operation.
VCA27
Voltage detection 2 enable
bit(4)
0 : Voltage detection 2 circuit disabled
1 : Voltage detection 2 circuit enabled
RW
VCA26
Voltage detection 1 enable
bit(3)
0 : Voltage detection 1 circuit disabled
1 : Voltage detection 1 circuit enabled
RW
000
0
b3 b2 b1 b0
b7 b6 b5 b4
The LVD0ON bit in the OFS register is
set to 1 and hardw are reset
: 00h
Pow er-on reset, voltage monitor 0 reset
or LVD0ON bit in the OFS register is
set to 0, and hardw are reset
: 00100000b
VCA25
Voltage detection 0 enable
bit(2)
0 : Voltage detection 0 circuit disabled
1 : Voltage detection 0 circuit enabled
RW
—
(b4-b1)
Reserved bits
Set to 0.
RW