CHAPTER 20 UART/SIO
20.4
Pins of UART/SIO
This section describes the pins related to the UART/SIO.
Pins Related to UART/SIO
The pins associated with UART/SIO are the clock input and output pin (UCK0), serial data output pin
(UO0) and serial data input pin (UI).
UCK0:
Clock input/output pin for UART/SIO.
When the clock output is enabled (SMC20:SCKE=1), it serves as a UART/SIO clock output pin (UCK0)
regardless of the value of the corresponding port direction register. At this time, do not select the external
clock (set SMC10:CKS = 0).
When it is to be used as a UART/SIO clock input pin, disable the clock output (SMC20:SCKE = 0) and
make sure that it is set as input port by the corresponding port direction register. At this time, be sure to
select the external clock (set SMC10:CKS = 0).
UO0:
Serial data output pin for UART/SIO. When the serial data output is enabled (SMC20:TXOE = 1), it
serves as a UART/SIO serial data output pin (UO0) regardless of the value of the corresponding port
direction register.
UI0:
Serial data input pin for UART/SIO. When it is to be used as a UART/SIO serial data input pin, make
sure that it is set as input port by the corresponding port direction register.
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