R8C/18 Group, R8C/19 Group
7. Voltage Detection Circuit
Rev.1.30
Apr 14, 2006
Page 43 of 233
REJ09B0222-0130
Figure 7.4
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 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
Set to 0.
0
b7 b6 b5 b4 b3 b2 b1 b0
0 0 0 0
The softw are reset, w atchdog timer reset, and voltage monitor 2 reset do not affect this register.
VCA13
Voltage detection 2 signal monitor
flag
(1)
0 0
—
(b2-b0)
RW
0 : VCC < Vdet2
1 : VCC
≥
Vdet2 or voltage detection 2
circuit disabled
RO
Reserved bits
Voltage Detection Register 2
(1)
After Reset
(4)
Symbol
Address
Hardw are reset : 00h
VCA2
0032h
Pow er-on reset, voltage monitor 1 reset
: 01000000b
Bit Symbol
Bit Name
Function
RW
NOTES:
1.
2.
3.
4.
b7 b6 b5 b4 b3 b2 b1 b0
0 0 0 0 0 0
—
(b5-b0)
Reserved bits
Set to 0.
RW
VCA26
Voltage detection 1 enable bit
(2)
0 : Voltage detection 1 circuit disabled
1 : Voltage detection 1 circuit enabled
RW
VCA27
Voltage detection 1 enable bit
(3)
0 : Voltage detection 2 circuit disabled
1 : Voltage detection 2 circuit enabled
RW
Set the PRC3 bit in the PRCR register to 1 (w rite enable) before w riting to this register.
To use the voltage monitor 1 reset, 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, and voltage monitor 2 reset do not affect this register.
