Renesas M32R/ECU Series User Manual page 836

Appendix 4
Appendix 4.13.5 Processing Input/Output Ports
For input/output ports, take the appropriate measures in both hardware and software following the procedure
described below.
Hardware measures
• Insert resistors of 100Ω or more in series to the input/output ports.
Software measures
• For input ports, read out data in a program two or more times to verify that the levels coincide.
• For output ports, rewrite the data register at certain intervals because there is a possibility of the output data
being inverted by noise.
• Rewrite the direction register at certain intervals.
Figure 4.13.11 Example Processing of Input/Output Ports
Data bus
Direction register
Data register
Appendix 4-31
SUMMARY OF PRECAUTIONS
Appendix 4.13 Precautions about Noise
Noise
Noise
Input/output port
32180 Group User's Manual (Rev. 1.0)