Although there is only one physical pin per SCI/UART channel for RTS/CTS, you can do full RTS/CTS flow control. First select Custom in the pins configurations for the SCI channel and select a pin for CTS_RTS_SS.
Then, in Threads tab select the UART module and set the CTS/RTS Selection to CTS. This assigns the CTS_RTS_SS pin to CTS operation. Next, set the External RTS Operation to Enabled and "Name of UART callback function for RTS external pin..." to a user defined callback to process RTS events. You have to use a GPIO (configured as output) for RTS and control it in the user callback.
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