R8C/18 Group, R8C/19 Group
16. Comparator
Rev.1.30
Apr 14, 2006
Page 170 of 233
REJ09B0222-0130
Figure 16.5
Registers ADCON0 and ADCON1 in Repeat Mode
A/D Control Register 0
(1)
Symbol
Address
After Reset
ADCON0
00D6h
00000XXXb
Bit Symbol
Bit Name
Function
RW
NOTES:
1.
2.
3.
4.
5.
When changing comparator conversion operating mode, set the analog input pin again.
Set the øAD frequency to 10 MHz or below .
CKS0
Frequency select bit 0
[When CKS1 in ADCON1 register = 0]
0 : Selects f4.
1 : Selects f2.
[When CKS1 in ADCON1 register = 1]
0 : Selects f1.
(4)
1 : fRING-fast
RW
If the ADCON0 register is rew ritten during comparator conversion, the conversion result is undefined.
Bits CH0 to CH2 are enabled w hen the ADGSEL0 bit is set to 1. After setting the ADGSEL0 bit to 1, w rite to bits CH0
to CH2.
ADST
Comparator conversion
start flag
0 : Disables comparator conversion.
1 : Starts comparator conversion.
RW
CH1
RW
CH0
ADCAP
Comparator conversion
automatic start bit
0 : Starts at softw are trigger (ADST bit).
1 : Starts at capture (requests timer Z interrupt).
RW
ADGSEL0
RW
Analog input group select
bit
(5)
0 : Disabled
1 : Enabled (AN8 to AN11)
RW
Analog input pin select
bits
(2)
b2 b1 b0
1 0 0 : AN8
1 0 1 : AN9
1 1 0 : AN10
1 1 1 : AN11
Other than above : Do not set.
1 : Repeat mode
RW
RW
Comparator conversion
operating mode select bit
(3)
b1
1
b7 b6 b5 b4
MD
CH2
To use the comparator, set the ADGSEL0 bit to 1.
b0
1
1
b3 b2
A/D Control Register 1
(1)
Symbol
Address
After Reset
ADCON1
00D7h
00h
Bit Symbol
Bit Name
Function
RW
NOTE:
1.
b3 b2 b1 b0
0
0
0
Refer to the description of the CKS0 bit in the
ADCON0 register function.
—
(b3-b0)
0
Reserved bits
Set to 0.
b7 b6 b5 b4
0 0 0
RW
Set to 0.
Frequency select bit 1
If the ADCON1 register is rew ritten during comparator conversion, the conversion result is undefined.
CKS1
RW
RW
—
(b7-b5)
Reserved bits