The oversampling mode is selected when UCOS16 = 1. This mode supports sampling a UART bitstream with higher input clock frequencies. This results in majority votes that are always 1/16 of a bit clock period apart. This mode also easily supports IrDA pulses with a 3/16 bit time when the IrDA encoder and decoder are enabled.
This mode uses one Prescaler and one modulator to generate the BITCLK16 clock which is 16 times faster than the BITCLK. An additional divider and modulator stage generates BITCLK from BITCLK16. This combination supports fractional divisions of both BITCLK16 and BITCLK for a baud-rate generation. In this mode, the maximum USCI baud rate is 1/16 the UART source clock frequency BRCLK. When UCBRx is set to 0 or 1, the first Prescaler and modulator stage is bypassed and BRCLK is equal to BITCLK16 – in this case, no modulation for the BITCLK16 is possible and, thus, the UCBRFx bits are ignored. Modulation for BITCLK16 is based on the UCBRFx setting (see Table 36-3). A 1 in the table indicates that the corresponding BITCLK16 period is one BRCLK period longer than the periods m = 0. The modulation restarts with each new bit timing. Modulation for BITCLK is based on the UCBRSx setting (see Table 36-2) as previously described.
