The SIR receive decoder demodulates the return-to-zero bitstream from the infrared detector and outputs the received NRZ serial bitstream to the UART received data input. The decoder input is normally High (marking state) in the idle state. The transmit encoder output has the opposite polarity to the decoder input.
A start bit is detected when the decoder input is Low.
- 3/16 of Baud16, in IrDA mode
- 3/16 of IrLPBaud16, in low-power IrDA mode