R01UH0822EJ0100 Rev.1.00
Page 893 of 1041
Jul 31, 2019
RX13T Group
28. Comparator C (CMPC)
28.2.3
Comparator Reference Voltage Select Register (CMPSEL1)
Note 1. When the on-chip D/A converter output voltage is used, set the D/A converter for generating comparator C reference voltage
before enabling comparator operation (CMPCTL.HCMPON bit = 1). For details on setting the D/A converter, refer to section 27,
D/A Converter for Generating Comparator C Reference Voltage (DA).
Note 2. Rewrite the CVRS[1:0] bits in the following procedure. Be sure to set the CVRS[1:0] bits to 00b before changing the set value.
Direct rewriting from 01b to 10b or 10b to 01b, for example, will be ignored even if it is tried.
(1) Set the CMPCTL.COE bit to 0.
(2) Set the CVRS[1:0] bits to 00b.
(3) Set a new value to the CVRS[1:0] bits (with 1 set in only one of the bits).
(4) Wait for the stabilization time for input selection. As for the value, refer to section 32, Electrical Characteristics.
(5) Set the CMPCTL.COE bit to 1.
(6) Set the corresponding interrupt status flag (IR) in the interrupt request register to 0.
Address(es): CMPC0.CMPSEL1 000A 0C88h, CMPC1.CMPSEL1 000A 0CA8h, CMPC2.CMPSEL1 000A 0CC8h
b7
b6
b5
b4
b3
b2
b1
b0
—
—
—
—
—
—
CVRS[1:0]
Value after reset:
0
0
0
0
0
0
0
0
Bit
Symbol
Bit Name
Description
R/W
b1, b0
Reference Input Voltage Select
*
b1 b0
0 0: No input
0 1: Input voltage to the CVREFC0 pin selected as reference
input voltage
1 0: On-chip D/A converter 0 output voltage selected as
reference input voltage
Settings other than above are prohibited.
R/W
b7 to b2
—
Reserved
These bits are read as 0. The write value should be 0.
R/W