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Renesas Electronics America - Knowledgebase

Interference when input pins & output pins are mixed w/ output pin side?

Latest Updated:12/01/2011


In the uPD780308, when input pins and output pins are mixed in the same port and the on-chip pull-up resistor is set to ON, does this cause interference with the output pin side?


No, this does not cause interference. (There is no problem.)
As can be seen in the port block diagram, the pull-up resistor of each port can only be enabled by setting the PUO register to 1 and also setting the PM register to 1 (in other words, input port mode).
Therefore, no pull-up resistor can be connected to a pin specified as output.
Suitable Products
RL78 Family
78K Family