Why can't I disable background calibration for the 25G Ethernet Intel® Stratix® 10 IP for the Intel® Stratix® 10 H-Tile Production FPGA devices?

Due to a problem in the Intel® Quartus® Prime Pro Edition software versions 18.1.2, 18.1.1 and 18.1, when using the soft 25G Ethernet Intel® Stratix® 10 IP Core for H-tile production devices, users may not be able to disable background calibration by writing 0 to register 0x542[0] of the transceiver control and status registers. 

To work around this problem, follow the steps below:

1. User will need to locate the Intel Quartus Prime IP file (.ip file) of the 25G Ethernet Intel® Stratix® 10 IP.

2. Search for SYNOPT_AUTO_ADAPTATION parameter in the .ip file. Change the <ipxact:value> value from 1 to 0.

                   <ipxact:parameter parameterId="SYNOPT_AUTO_ADAPTATION" type="int">
                   <ipxact:name>SYNOPT_AUTO_ADAPTATION</ipxact:name>
                   <ipxact:displayName>Enable auto adaptation triggering for RX PMA CTLE/DFE mode</ipxact:displayName>
                   <ipxact:value>0</ipxact:value>

3. Regenerate the 25G Ethernet Intel® Stratix® 10 IP. 

4. Recompile the design in the Intel® Quartus® Prime Pro Edition.

5. Write 0x0 into register 0x542[0] of the transceiver control and status registers using the transceiver reconfiguration Avalon* -MM interface to disable background calibration. Refer to Background Calibration section of the Intel® Stratix® 10 L- and H-Tile Transceiver PHY User Guide for more information about how to enable and disable background calibration.

6. Perform reconfiguration register accesses. 

7.  Enable background calibration by writing 0x1 to register 0x542[0]. If Adaption is desired, please refer to Adaptation Control - Start section of the Intel® Stratix® 10 L- and H-Tile Transceiver PHY User Guide for more information about how to start signal adaptation.