Mitsubishi Electric M32R Series User Manual page 843

Mitsubishi 32-bit risc single-chip microcomputers

Table of Contents

(2) Wiring of clock input/output pins

Reduce the length of wiring connecting to the clock input/output pins. When connecting a

capacitor to the oscillator, make sure its ground lead wire and the VSS pin on the microcomputer

are connected with the shortest possible wiring (within 20 mm). Also, make sure the VSS pattern

for clock oscillation is used for only the oscillator circuit and is separated from other VSS patterns.

The microcomputer operates synchronously with the clock generated by the oscillator circuit.

Inclusion of noise on clock input/output pins causes the clock waveform to become distorted,

which may result in the microcomputer operating erratically or getting out of control. Also, if a

noise-induced potential difference exists between the microcomputer's VSS level and the

oscillator's VSS level, the clock fed into the microcomputer may not be an exact clock.

Figure 3.1.2 Wiring of Clock Input/Output Pins

(3) Wiring of operation mode setup pins

When connecting operation mode setup pins and the VCC or VSS pin, make sure they are

connected with the shortest possible wiring.

The levels of operation mode setup pins affect the microcomputer's operation mode. When

connecting operation mode setup pins and the VCC or VSS pin, be careful that no noise-

induced potential difference will exist between operation mode setup pins and the VCC or

VSS pin. This is because the presence of such a potential difference makes operation mode

instable, which may result in the microcomputer operating erratically or getting out of control.

Figure 3.1.3 Example for Wiring of MOD0 and MOD1 Pins

Operation mode

Appendix 3-3

INSTRUCTION PROCESSING TIME

Appendix 3.1 Precautions about Noise

Operation mode