Serial data must be aligned to symbol boundaries before it can be used as parallel data. To make alignment possible, transmitters send a recognizable sequence, usually called a comma. The receiver searches for the comma in the incoming data. When it finds a comma, it moves the comma to a byte boundary so the received parallel words match the transmitted parallel words.
The figure below shows the alignment to a 10-bit comma. The RX receiving unaligned bits are on the right side. The serial data with the comma is highlighted in the middle. Byte aligned RX parallel data is on the left.
Figure 1. Conceptual View of Comma Alignment (Aligning to a 10-Bit Comma)
The figure below shows TX parallel data on the left side, and RX receiving recognizable parallel data after comma alignment on the right side.
Figure 2. Parallel Data View of Comma Alignment (RX_SHOW_REALIGN_COMMA = TRUE)
