Networking Interface for Open Programmable Acceleration Engine: Intel® Programmable Acceleration Card with Intel® Arria® 10 GX FPGA

ID 683532
Date 8/05/2019
Public
Document Table of Contents

3.2.3. Modifying HSSI PHY Transceiver PMA Settings

You can retrieve the current set of HSSI PHY transceiver analog PMA settings and modify individual settings per transceiver lane using the equalizer_tune sysfs file.

The following command dumps the current settings to stdout:

$ cat /sys/class/fpga/intel-fpga-dev.<i>/intel-fpga-fme.<j>/intel-pac-hssi.<m>.auto/hssi_mgmt/\
equalizer_tune

See The equalizer_tune sysfs for details on the format of this sysfs file’s contents.

To modify an analog PMA setting for a transceiver lane, write a single field at a time to the equalizer_tune sysfs file. For example, to set the transmitter pre-emphasis second pre-tap magnitude to 4 for transceiver lane 2, write the following string value:

"2:6=4"

Here is an example of doing this from a shell terminal window:

$ sudo sh -c "echo 2:6=4 > \
/sys/class/fpga/intel-fpga-dev.<i>/intel-fpga-fme.<j>/intel-pac-hssi.<m>.auto/hssi_mgmt/equalizer_tune"

Do this separately for each lane or PMA setting value you want to modify.