SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
Serial data from the transmit state-machine are encoded to transmit data to the optoelectronics. While the TX FIFO output is high, the uart3_irtx line is always low, and the counter used to form a pulse on uart3_irtx is cleared continuously.
After the TX FIFO output resets to 0, uart3_irtx rises on the falling edge of the seventh 16XCLK. On the falling edge of the tenth 16XCLK pulse, uart3_irtx falls, creating a 3-clock-wide pulse. While the TX FIFO output stays low, a pulse is transmitted during the seventh clock to the tenth clock of each 16-clock bit cycle.
Figure 24-42 shows the IrDA SIR encoding mechanism.