SPRUIE9D May 2017 – May 2024 DRA74P , DRA75P , DRA76P , DRA77P
Figure 10-36 shows the CAL video port internal architecture. It is composed of a timing generator and a FIFO. All four video ports have same architecture and take same register inputs.
The video port receives data + TAGs from the DPCM decoder stage. It filters the received data and only processes:
In addition, it uses the FE_CODE tag to enter the vertical blanking period after the end of the horizontal blanking period when the vertical blanking period is not already started.
Other data is ignored by the video port (this does not affect the operation of other pipeline stages).
Only one CPORT can use the video port and only pixel data can be sent to the video port (that is, control and attribute packets are ignored).
When the video port is configured in baseline mode (CTRL_CORE_SMA_SW_3[31] CAL_BASELINE_EN = 0x1), then only one CPORT can use Video Port 1 and only pixel data can be sent to Video Port 1 (that is, control and attribute packets are ignored).
When the video port is configured in VPx4 mode (CTRL_CORE_SMA_SW_3[31] CAL_BASELINE_EN = 0x0), then the video ports mapping is as follows:
Figure 10-36 CAL Video Port and Timing GeneratorThe FIFO receives data from the internal processing pipeline at a variable rate (up to 4 pixels per cycle). The HIGH signal is asserted a few cycles before the FIFO becomes full. It is used to stall the incoming pixel flow . Therefore, no FIFO overflow can occur.
The timing generator is started after a PIX_DAT_FS tag, when the FIFO level exceeds the threshold defined in CAL_VPORT_CTRL2[31:18] RDY_THR bit field. This threshold is 0 by default but may be used to smooth the traffic on the video port .
The timing generator controls pixel reads from the FIFO. It only reads a pixel when: