
R8C/38T-A Group
24. Comparator B
Under development Preliminary document
Specifications in this document are tentative and subject to change.
R01UH0241EJ0010 Rev.0.10
Page 566 of 730
Aug 05, 2011
24. Comparator B
Comparator B compares a reference input voltage to an analog input voltage. Comparator B1 and comparator B3 are
independent of each other.
24.1
Overview
The comparison result of the reference input voltage and analog input voltage can be read by software. An input to
the IVREFi (i = 1 or 3) pin can be used as the reference input voltage.
i = 1 or 3
Figure 24.1
Comparator B Block Diagram
Table 24.1
Comparator B Specifications
Item
Specification
Analog input voltage
Input voltage to the IVCMPi pin
Reference input voltage
Input voltage to the IVREFi pin
Comparison result
Read from the INTiCOUT bit in the INTCMP register
Interrupt request generation timing
When the comparison result changes.
Selectable function
Digital filter function
Whether the digital filter is used or not and the sampling frequency can be
selected.
+
-
INT3F1 and INT3F0
= 01b
= 10b
= 11b
INT1CP0, INT1COUT, INT3CP0, INT3COUT: Bits in INTCMP register
INT1EN, INT1PL, INT3EN, INT3PL: Bits in INTEN register
INT1F0, INT1F1, INT3F0, INT3F1: Bits in INTF register
f1
f8
f32
Digital filter
(match 3 times)
INT3CP0 = 0
Sampling clock
INT3COUT
INT3
Port direction register
IVCMP3
IVREF3
INT3CP0 = 1
= other than 00b
INT3F1 and INT3F0
= 00b
INT3PL = 0
INT3PL = 1
To INT3 interrupt
INT3EN
Digital filter
(match 3 times)
INT1CP0 = 1
INT1CP0 = 0
= other than 00b
INT1F1 and INT1F0
= 00b
INT1PL = 0
INT1PL = 1
To INT1 interrupt
INT1EN
INT1F1 and INT1F0
= 01b
= 10b
= 11b
f1
f8
f32
Sampling clock
INT1COUT
INT1
Port direction register
+
-
IVCMP1
IVREF1
Both-edge
detection
circuit
Both-edge
detection
circuit