SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
In embedded sync mode, code words are inserted into the stream at pixel clock rates. For external devices that send out 10 bits (single pixel interface) or 20 bits (parallel Y-Cb/Cr interface) of data, only the 8 (single pixel interface) or 16 (parallel 8bY-8bCb/Cr interface) most significant bits of each pixel are used.
The key code words are Start of Active Video (SAV) and End of Active Video (EAV). Three flags are found in these code words: F (field), V (vertical sync), and H (horizontal sync). These flags signify the position in the frame corresponding to the data immediately following the codeword. The flags determine whether the code is EAV or SAV and where they lie in the picture. The first byte of the code word is 0xFF. The second and third bytes are 0x00. The bit ordering of the fourth byte is detailed in Table 11-10.
| 7 (fixed) | 6 (F) | 5 (V) | 4 (H) | 3 (P3=V^H) | 2 (P2=F^H) | 1 (P1=F^V) | 0 (P0=F^V^H) | Description |
|---|---|---|---|---|---|---|---|---|
| 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | SAV, Field 0, Active Video |
| 1 | 0 | 0 | 1 | 1 | 1 | 0 | 1 | EAV. Field 0, Horizontal Blanking |
| 1 | 0 | 1 | 0 | 1 | 0 | 1 | 1 | SAV, Field 0, Vertical Blanking |
| 1 | 0 | 1 | 1 | 0 | 1 | 1 | 0 | EAV, Field 0, Horizontal Blanking in Vertical Blanking Region |
| 1 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | SAV, Field 1, Active Video |
| 1 | 1 | 0 | 1 | 1 | 0 | 1 | 0 | EAV, Field 1, Horizontal Blanking |
| 1 | 1 | 1 | 0 | 1 | 1 | 0 | 0 | SAV, Field 1, Vertical Blanking |
| 1 | 1 | 1 | 1 | 0 | 0 | 0 | 1 | EAV, Field 1, Horizontal Blanking in Vertical Blanking Region |
An example of the input ordering of the embedded code word, followed by active video, is shown in Figure 11-44. The input data mode is 8 bits for the example.
Figure 11-44 Code Word Format Example Followed by Video Data