SDI IP Core User Guide

ID 683587
Date 8/20/2020
Document Table of Contents

3.3.4. Receiver Transceiver Interface

Intel provides a transceiver interface, which interfaces the transceiver to the SDI function.
The receiver transceiver interface implements the following functions:
  • Receiver oversampling for SD-SDI
  • Transceiver controller

SD-SDI Receiver Oversampling

Arria II GX, Arria V, Stratix IV, and Stratix V transceivers do not support CDR for data rates less than 600 Mbps. The receiver uses fixed frequency oversampling for the reception of 270-Mbps SD-SDI. The transceiver samples the serial data at 1,350 or 2,970 Mbps and the SD-SDI receiver oversampling logic extracts the original 270 Mbps data.

Figure 16. Receiver Data TimingThis figure shows an example of the receiver data timing.

Transceiver Controller

To achieve the desired receiver functionality for the SDI, the transceiver controller controls the transceiver.

When the interface receives SD-SDI, the transceiver receiver PLL locks to the receiver reference clock.

When the interface receives HD-SDI, the transceiver receiver PLL is first trained by locking to the receiver reference clock. When the PLL is locked, it can then track the actual receiver data rate. If a period of time passes without a valid SDI signal, the PLL is retrained with the reference clock and the process is repeated.

First, the transceiver controller makes a coarse rate detection of the incoming data stream. Through transceiver dynamic reconfiguration, the transceiver is then reprogrammed to the correct rate for the standard detected. After the reprogramming, the transceiver attempts to lock to the incoming stream. If no valid data is seen in 0.1 s, the transceiver resets the receiver path and performs rate detection again.

At the start of the rate detection process, the level of the three enable_xx signals is sampled. The level of these signals and the knowledge of the currently programmed state of the transceiver determines if the transceiver requires programming. This process ensures that the transceiver is reprogrammed only when necessary.