When operating in CSI-2 Mode, the receives CSI-2 formatted data on up to four FPD-Link III input ports and forwards the data to one or two CSI-2 transmit ports. The deserializer can operate in CSI-2 mode with synchronous back channel reference or non-synchronous mode. The forward channel line rate is independent of the CSI-2 rate in synchronous or non-synchronous with external clock mode. The mode supports the remapping of Virtual Channel IDs at the input of each receive port. This remapping allows the receivers to handle conflicting VC-IDs for input streams from multiple sensors and to send those streams to the same CSI-2 transmit port.

In CSI-2 mode each deserializer Rx Port can support an FPD-Link III line rate up to 4.16 Gbps, where the line (or forward channel) and back channel rates are based on the reference frequency used for the serializer:

• In Synchronous mode based on REFCLK input frequency reference, the FPD-Link III forward channel rate is a fixed value of 160 × REFCLK. FPD3_PCLK = 4 × REFCLK and back channel rate = 2 × REFCLK. For example with REFCLK = 25 MHz, forward channel data rate = 4.0 Gbps, FPD3_PCLK = 100 MHz, back channel data rate = 50 Mbps.
• In Non-synchronous clocking mode when the DS90UB953-Q1 uses external reference clock (CLK_IN) the FPD-Link line rate is typically CLK_IN × 80, FPD3_PCLK = 2 × CLK_IN (CLK_IN = 25 - 52 MHz) or 1 x CLK_IN (CLK_IN = 50 - 104 MHz), based on serializer CLKIN_DIV selection. The back channel data rate must be set to 10 Mbps using Register 0x58. For example, with CLK_IN = 50 MHz, forward channel rate = 4 Gbps, FPD3_PCLK = 100 MHz, REFCLK = 25 MHz, and the back channel rate is 10 Mbps. The sensor CSI-2 rate is independent of the CLK_IN.