Video stream forwarding is handled by the forwarding control in the DS90UB662-Q1 on FWD_CTL1 register 0x20 (Table 7-50). The forwarding control pulls data from the video buffers for each FPD3 RX port and forwards the data to one of the CSI-2 output interfaces. It also handles generation of transitions between LP and HS modes as well as sending of Synchronization frames. The forwarding control monitors each of the video buffers for packet and data availability.

Forwarding from input ports may be disabled using per-port controls. Each of the forwarding engines may be configured to pull data from any of the four video buffers, although a buffer may only be assigned to one CSI-2 Transmitter at a time. The two forwarding engines operate independently. Video buffers are assigned to the CSI-2 Transmitters using the mapping bits in the FWD_CTL1 register 0x20[7:4].