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R01UH0823EJ0100 Rev.1.00 Page 1635 of 1823

Jul 31, 2019

RX23W Group 47. Comparator B (CMPBa)

47. Comparator B (CMPBa)

Comparator B compares a reference input voltage and an analog input voltage. comparator B2 and comparator B3

operate independently.

In this section, “PCLK” is used to refer to PCLKB.

47.1 Overview

The comparison result of the reference input voltage and analog input voltage can be read by software. The comparison

result can also be output externally. The reference input voltage can be selected from either an input to the CVREFBn pin

(n = 2, 3)

or the internal reference voltage generated internally in the MCU.

The comparator B response speed can be set before starting an operation. Setting high-speed mode decreases the

response delay time, but increases current consumption. Setting low-speed mode increases the response delay time, but

decreases current consumption.

Table 47.1 lists the specifications of comparator B, Figure 47.1 shows a block diagram of comparators B2 and B3

when the window function is disabled, and

Figure 47.2 shows a block diagram of comparators B2 and B3 when the

window function is enabled.

Table 47.2 lists the I/O pins of comparator B.

Note 1. VRFL: low-side reference voltage, VRFH: high-side reference voltage

Table 47.1 Comparator B Specifications (n = 2, 3)

Item Specification

Analog input voltage Input voltage to the CMPBn pin

Reference input voltage Input voltage to the CVREFBn pin or internal reference voltage

Comparison result Read from the CPBFLG.CPBnOUT flag

The comparison result can be output to the CMPOBn pin.

Interrupt request generation timing When comparator B2 comparison result changes

When comparator B3 comparison result changes

Selectable function

 Digital filter function

Whether the digital filter is applied or not, and the sampling frequency can be selected.

 Window function

Whether the window function is enabled or disabled (VRFL < CMPBn < VRFH)*

can be

selected.

 Reference input voltage

CVREFBn pin input or internal reference voltage (generated internally) can be selected.

 Comparator B response speed

High-speed mode/low-speed mode can be selected.

Low power consumption function Module stop state can be set.

Renesas RX Series User Manual

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