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Renesas Electronics Europe - Knowledgebase

Is it true that serial port setting is a priority than I/O port setting?

Latest Updated:12/01/2011


I have been using the 78K/0 until now.
In the 78K/0, complicated settings such as P2 and PM2 were required for serial port I/O.
The P2 I/O port settings influence the serial port operation.
The 78K/4 User's Manual (Document No. U13570) does not include a description of I/O port settings related to serial port settings.
I interpret this to signify that serial port settings are a higher priority than I/O port settings. Is this interpretation correct?


No, it isn't.
If you refer to the block diagram of the ports with alternate functions, you can see that PM2 and P2 settings are required.
Concretely, 0 must be written to the P2 output latch corresponding to the pins used serially, 1 must be written to PM2 for the pins used as input serially, and PM2 must be set to 0 for pins used as output.
Suitable Products
78K Family