Visible to Intel only — GUID: hco1410462449069
Ixiasoft
Visible to Intel only — GUID: hco1410462449069
Ixiasoft
6.6. Sink Clock Tree
The IP receives DisplayPort serial data across the high-speed serial interface (HSSI). The HSSI requires a 135 MHz clock for correct data locking. You can supply this frequency to the HSSI using a reference clock provided by an Intel FPGA PLL or pins.
The IP synchronizes HSSI 20- or 40-bit data to a single HSSI[0] clock that clocks the data into the DisplayPort front-end decoder.
- If you select dual symbol mode, this clock is equal to the link rate divided by 20 (270, 135, or 81 MHz).
- If you turn on quad symbol mode, this clock is equal to the link rate divided by 40 (202.5, 135, 67.5, or 40.5 MHz).
- If rxN_vid_clk is slower than the up-stream video clock, the DCFIFO overflows.
- If the rxN_vid_clk is faster than the up-stream source video clock, the output port experiences a deassertion of the valid port on cycles in which pixel data is not available.
The optimum frequency is the exact clock rate in the up-stream source. You require pixel clock recovery techniques to determine this clock frequency.
Secondary stream data is clocked by rx_ss_clk. The sink IP also requires a 16-MHz clock (aux_clk) to drive the internal AUX controller and an Avalon clock for the Avalon® memory-mapped interface (clk).