LVDS Transceiver for 7 Series and Zynq 7000 Devices - 16.2 English

1G/2.5G Ethernet PCS/PMA or SGMII LogiCORE IP Product Guide (PG047)

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16.2 English

The LVDS transceiver block fully replaces the functionality otherwise provided by a 7 series device transceiver. This is only possible at a serial line rate of 1.25 Gbps. The following figure shows a block diagram of the LVDS transceiver for Zynq 7000 and 7 series devices. This is split up into several sub-blocks which are described in further detail in the following sections.

On the transmitter path, data sourced by the core netlist is routed through the 8B/10B Encoder to translate the 8-bit code groups into 10-bit data. The 10-bit data is then passed through the 10B6B Gearbox and the parallel data is then clocked out serially at a line rate of 1.25 Gbps.

The receiver path has additional complexity. Serial data received at 1.25 Gbps is routed in parallel to two IODELAYs and ISERDES. Logic is provided to find the correct sampling point in the eye monitor and Phy calibration blocks.

The 6-bit parallel data is fed to the 6B10B gearbox which converts it into 10-bit parallel data. Having recovered parallel data from the serial stream, the Comma Alignment module, next on the receiver path, detects specific 8B/10B bit patterns (commas) and uses these to realign the 10-bit parallel data to contain unique 8B/10B code groups. These code groups are then routed through the 8B/10B Decoder module to obtain the unencoded 8-bit code groups that the core netlist can accept.

Figure 1. LVDS Transceiver Block Level for 7 Series and Zynq 7000 Devices 8B10B Encoder 10B6B Gearbox 8B10B Decoder 6B10B Gearbox ISERDESE2 Monitor Serial -> 6 bits ISERDESE2 Data Serial -> 6 bits Eye Monitor o_rx_mon o_rx_data_12b Phy Callibration OSERDESE2 6 bits -> Serial IDELAYE 2 IDELAYE 2 OBUFDS IBUFDS_DIFF _OUT rxn rxp txn txp IB I OB O OB O I <component_name>_sgmii_phy_iob <component_name>_gpio_sgmii_top <component_name>_lvds_transceiver From Core To Core 6 bit data 6 bit data X12957 CommaAlignment

The following files describe the top level of the hierarchal levels of the LVDS transceiver:

<project_dir>/<project_name>/<project_name>.srcs/sources1/ip/<component_name>/ synth/lvds_transceiver/<component_name>_lvds_transceiver.v[hd]