1 Transceiver Tuning

Transceiver tuning for PolarFire devices can be done in three different ways:

  • Traditional Method (Non-simulation flow): Traditional method is based on learning from experience. If the channel loss is a known parameter then based on the recommendations provided in this document or on the basis of your experience, transceiver attributes are loaded to the device.
    Important: This method does not ensure the ideal transceiver performance.
  • IBIS-AMI Simulations: Transceiver tuning based on IBIS-AMI Simulations is the best method available so far:
    • Confidence on the hardware based on simulation results.
    • Variables for both transmitter and receiver change and outcome is monitored dynamically.
    • Clear image on how the different transceiver attributes impact the performance of the system.
    The appropriate transceiver attributes obtained from the simulation can be applied to the device in two ways:
    • Libero® SoC: Changes the attributes in the design, while generating the bit file.
    • Through SmartDebug: The tool provides the facility to vary between the multiple attributes using the same bit file. Detailed explanation of tuning using IBIS-AMI simulations is provided in this document.
  • SmartDebug: It is used for debugging the Transceiver using electrical parameters such as Tx amplitude, De-emphasis, driver impedance, Rx impedance, Continuous Time Linear Equalization (CTLE) and Decision Feedback Equalization (DFE) calibration. It gives you a freedom to change the signal integrity settings based on the simulations or intuitions. Details of SmartDebug are discussed in the later section of this document. For more information, see PolarFire FPGA SmartDebug User Guide.
Important: Receiver optimization was disabled in Libero SoC v12.0 SmartDebug. It will be fixed in a future version.

PolarFire transceivers have a memory-mapped Dynamic Reconfiguration Interface (DRI) that allows SmartDebug to communicate with the transceiver blocks in real time. This feature provides debugging and altering capabilities of the transceivers for optimized performance in the system. After the final SmartDebug signal integrity optimization, you can export the tuned information back into the Libero SoC software for future design regeneration.

The following figure illustrates the process for optimizing the signal integrity of a transceiver.

Figure 1-1. Transceiver Signal Integrity Tuning Flow