Universal synchronous asynchronous receiver transmitter (USART) UM0306
380/519
IrDA_RDI: Receive Data Input is the data input in IrDA mode.
IrDA_TDO: Transmit Data Output in IrDA mode.
Following pins are required in modem mode:
nCTS: Clear To Send blocks the data transmission at the end of the current transfer when
high
nRTS: Request to send indicates that the USART is ready to receive a data (when low).