Mitsubishi Electric M32R Series User Manual page 845

Mitsubishi 32-bit risc single-chip microcomputers

Table of Contents

Appendix 3.1.3 Processing Analog Input Pin Wiring

Connect a resistor of about 100 to 500 Ω ( in series to the analog signal wire connecting to the

analog input pin at a position as close to the microcomputer as possible. Also, insert a capacitor of

about 100 pF between the analog input pin and AVSS pin at a position as close to the AVSS pin as

The signal fed into the analog input pin (e.g., A-D converter input pin) normally is an output

signal from a sensor. In many cases, a sensor to detect changes of event is located apart from

the board on which the microcomputer is mounted, so that wiring to the analog input pin

inevitably is long. Because a long wiring serves as an antenna which draws noise into the

microcomputer, the signal fed into the analog input pin tends to be noise-ridden. Furthermore, if

the capacitor connected between the analog input pin and AVSS pin is grounded at a position

apart from the AVSS pin, noise ridding on the ground line may penetrate into the microcomputer

via the capacitor.

Figure 3.1.5 Resistor and Capacitor for Analog Signal Line

Appendix 3-5

INSTRUCTION PROCESSING TIME

Appendix 3.1 Precautions about Noise