
R8C/3GM Group
6. Voltage Detection Circuit
R01UH0284EJ0100 Rev.1.00
Aug 09, 2011
6.2.4
Voltage Detect Register 2 (VCA2)
Notes:
1. Use the VCA20 bit only when the MCU enters wait mode. To set the VCA20 bit, follow the procedure shown in
32.2.9 Reducing Internal Power Consumption Using VCA20 Bit
.
2. When the VCA20 bit is set to 1 (low consumption enabled), do not set the CM10 bit in the CM1 register to 1 (stop
mode).
3. When writing to the VCA25 bit, set a value after reset.
4. To use the voltage detection 1/comparator A1 interrupt or the VW1C3 bit in the VW1C register, set the VCA26 bit
to 1.
After the VCA26 bit is set to 1 from 0, allow td(E-A) to elapse before the voltage detection 1/comparator A1 circuit
starts operation.
5. To use the voltage detection 2/comparator A2 interrupt or the VCA13 bit in the VCA1 register, set the VCA27 bit
to 1.
After the VCA27 bit is set to 1 from 0, allow td(E-A) to elapse before the voltage detection 2/comparator A2 circuit
starts operation.
Set the PRC3 bit in the PRCR register to 1 (write enabled) before rewriting the VCA2 register.
Address 0034h
Bit
b7b6
b5b4b3b2
b1
b0
Symbol
VCA27
VCA26
VCA25
VCA24
VCA23
VCA22
VCA21
VCA20
After Reset
0
000
0000
The above applies when the LVDAS bit in the OFS register is set to 1.
After Reset
0
010
0000
The above applies when the LVDAS bit in the OFS register is set to 0.
Bit
Symbol
Bit Name
Function
R/W
b0
VCA20
Internal power low consumption
enable bit (1)
0: Low consumption disabled
1: Low consumption enabled (2)
R/W
b1
VCA21
Comparator A1 reference voltage
input select bit
0: Internal reference voltage
1: LVREF pin input voltage
R/W
b2
VCA22
LVCMP1 comparison voltage
external input select bit
0: Supply voltage (VCC)
1: LVCMP1 pin input voltage
R/W
b3
VCA23
Comparator A2 reference voltage
input select bit
0: Internal reference voltage
1: LVREF pin input voltage
R/W
b4
VCA24
LVCMP2 comparison voltage
external input select bit
0: Supply voltage (VCC) (Vdet2_0)
1: LVCMP2 pin input voltage (Vdet2_EXT)
R/W
b5
VCA25
Voltage detection 0 enable bit (3)
0: Voltage detection 0 circuit disabled
1: Voltage detection 0 circuit enabled
R/W
b6
VCA26
Voltage detection 1/comparator A1
enable bit (4)
0: Voltage detection 1/comparator A1 circuit disabled
1: Voltage detection 1/comparator A1 circuit enabled
R/W
b7
VCA27
Voltage detection 2/comparator A2
enable bit (5)
0: Voltage detection 2/comparator A2 circuit disabled
1: Voltage detection 2/comparator A2 circuit enabled
R/W