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Is input or output of TxD and RxD pins determined by the serial I/O?

Latest Updated:03/01/2005

Question:

(Serial Interface)  Is the input or output of pins assigned to TxD and RxD automatically determined by the serial I/O function? Does the port direction register need to be set? [2005/03/01]

Answer:

The pins assigned to TxD/RxD are forcibly determined by control bits related to the serial I/O.
(1) TxD pin is set for output when the serial I/O enable bit is "1" and the transmit enable bit is "1", regardless of the port direction register setting.
(2) RxD pin is set for input when the serial I/O enable bit is "1" and the receive enable bit is "1", regardless of the port direction register setting.

(#104796)

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