Stratix V Device Handbook: Volume 2: Transceivers

ID 683779
Date 11/23/2021
Document Table of Contents

4.8.5. PMA Direct Supported Features

The PMA Direct is used to support protocols that require extremely low or zero transceiver PCS latency such as QPI. In PMA Direct mode, the transceiver can reach lane data rates up to 14.1 Gbps with the widest FPGA fabric-to-transceiver interface width configuration.

There are no PCS blocks in the PMA Direct configuration, so clock phase compensation must be designed in the fabric core. Data and clock signals are interfaced directly to the transceiver PMA. Consequently, you must also compensate for the timing and clock phase differences from the core fabric interface of the FPGA to the transceiver PMA. The PMA interface width has a wide range of selections from 8-bit, 10-bit, 16-bit, 20-bit, 32-bit, 40-bit, 64-bit, and 80-bit. The FPGA fabric interface width is fixed at 80-bit and you must select the correct ports for their PMA interface width configurations.

To implement a Native PHY link with the PMA Direct datapath, instantiate the Transceiver Native PHY IP in the IP Catalog, under Transceiver PHY in the Interfaces menu. Do not select the options to enable the Standard or 10G PCS. The Standard and 10G PCS tabs do not appear, indicating that the PMA Direct datapath configuration has been selected.

Figure 158 shows the transceiver PMA Direct datapath and clocking in the device channels.