Users Manual

Table Of Contents
R01UH0823EJ0110 Rev.1.10 Page 1047 of 1852
Nov 30, 2020
RX23W Group 33. Serial Communications Interface (SCIg, SCIh)
33.5.2 CTS and RTS Functions
In the CTS function, CTSn# pin input is used to control reception/transmission start when the clock source is the internal
clock. Setting the SPMR.CTSE bit to 1 enables the CTS function.
When the CTS function is enabled, placing the low level on the CTSn# pin causes reception/transmission to start.
Applying the high level to the CTS# pin while reception/transmission are in progress does not affect reception/
transmission of the current frame, which continues.
In the RTS function, RTSn# pin output is used to request reception/transmission start when the clock source is an
external synchronizing clock. A low level is output when serial communications become possible. Conditions for output
of the low and high level are shown below.
[Conditions for low-level output]
When the following conditions are all satisfied.
The SCR.RE or SCR.TE bit is 1.
Transmission or reception is not in progress.
There are no received data yet to be read (when the SCR.RE bit is 1).
Untransmitted data is present (when the SCR.TE bit is 1).
The SSR.ORER flag is 0.
[Condition for high-level output]
The conditions for low-level output have not been satisfied.