SLAU962A December 2025 – June 2026 MSPM33C321A , MSPM33C321A-Q1
This section applies to UNICOMM-UART configurations which support the UART-IRDA feature.
When IREN bit in IRCTL register is set, the IrDA encoder and decoder are enabled and provide hardware bit shaping for IrDA communication. IrDA encoding & decoding should only be used with UART mode (CTL0.MODE is 0). Only odd dividers of CLKDIV are support in this mode.
IrDA Encoding
The encoder sends a pulse for every zero bit in the transmit bit stream coming from the UART (see Figure 22-15). The pulse duration is defined by IRTXPL bits specifying the number of one-half clock periods of the clock selected by IRTXCLK bit.
IrDA Decoding
The decoder detects high pulses when IRRXPL = 0. Otherwise, it detects low pulses.
A programmable digital filter stage can be enabled by setting UARTx.GFCTL.DGFSEL > 0. When IRCTL.IREN is set, also the digital glitch filter should be set so that only pulses longer than the programmed filter length are passed and shorter pulses are discarded. (See the Glitch Suppression chapter on how to set the filter.)