Data Formatter - 5.0 English

Video In to AXI4-Stream LogiCORE IP Product Guide (PG043)

Document ID
PG043
Release Date
2021-10-22
Version
5.0 English

The data formatter derives the EOL and SOF flags required to transmit AXI4-Stream Video protocol. It also controls writing of the FIFO in the stream coupler. The flags are generated by looking at the edges of the data valid ( vid_active_video ) signal. Since only active pixels are carried on AXI4-Stream, the FIFO is only written when active pixels are present. There are input registers on all inputs to minimize input loading. The EOL flag is timed to be coincident with the last pixel before the falling edge of DE . Video data is delayed so that the falling edge of DE can be detected, and the EOL flag asserted coincident with the proper pixel as it is written to the FIFO. Similarly, the SOF flag is created based on the rising edge of DE , however it additionally requires knowledge of the vertical timing to identify the first line. This is done using the logical or OR vsync and vblank . The falling edge of either of these indicates that the input video is in the vertical blanking period. This enables SOF generation, and the SOF flag is asserted at the next rising edge of DE ; the first valid pixel of the field.

The rising edge of DE also resets the vertical blanking flip-flop. This Figure shows the timing of outputs and internal signals relative to the inputs. The de_1 and de_2 signals are delayed versions of de . The outputs are highlighted in bold.

Figure 3-6: Data Formatter Timing Diagram

X-Ref Target - Figure 3-6

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