SPRUIU1C July 2020 – February 2024 DRA821U , DRA821U-Q1
To allow complete software flexibility when transmitting and receiving infrared data packets, the SIR free-format (FF) mode is a subfunction of the existing SIR mode. In FF mode, all frames going to and from the FIFO buffers are untouched with respect to appending and removing control characters and CRC values.
The FF mode corresponds to a UART mode with a pulse modulation of 3/16 of baud rate pulse width.
For example, a normal SIR packet has BOF control and CRC error-checking data appended (transmitting) or removed (receiving) from the data going to and from the FIFOs.
Figure 12-391 shows SIR FF mode.
In SIR FF mode, the Host CPU software must construct (that is, encode and decode) the entire FIFO data packet.