Why does refclk_fgt_enabled_i in the F-Tile Reference and System PLL Clocks IP fail to assert even after in_refclk_fgt_i is active and stable and en_refclk_fgt_i is asserted?

Description

Due to a problem in the Quartus® Prime Pro Edition Software version 26.1.1 and earlier, you might observe refclk_fgt_enabled_i in the F-Tile Reference and System PLL clocks IP fail to lock.

Background:

When the FGT PMA reference clock source is not active at configuration, then you must unselect below parameter:

 

And the F-Tile Reference and System PLL Clocks FPGA IP will expose below control and status signals for each FGT PMA:

• en_refclk_fgt_i

• refclk_fgt_enabled_i

 

Expected behavior:

For each FGT PMA, after its reference clock source #i is active, then we can drive en_refclk_fgt_i to get refclk_fgt_enabled_i asserted.

 

Root Cause:

During support logic generation, Quartus creates a shared AVMM arbiter for the F-Tile Reference and System PLL Clocks IP internal datapath AVMM master and the F-Tile protocol IP datapath AVMM masters. In certain corner cases, the internal datapath AVMM master of the F-Tile System PLL IP is connected to a different reconfiguration clock source than the one used by the F-Tile protocol IP datapath AVMM masters. This clock mismatch causes the shared AVMM arbiter to malfunction, resulting in failed datapath AVMM transactions. As a result, the F-Tile System PLL IP internal state machine cannot complete its initialization sequence, and refclk_fgt_enabled_i remains deasserted.

Resolution

To work around this problem, you can apply below methods:

• For Quartus® Prime Pro Edition Software version 25.1.1, apply patch 1.53.
• For other Quartus® Prime Pro Edition Software versions, disable the F-Tile protocol IP datapath AVMM interface. As a result, no shared AVMM arbiter is generated between the F-Tile protocol IP datapath AVMM masters and the internal datapath AVMM master of the F-Tile System PLL IP.

This problem is scheduled to be resolved in a future release of the Quartus® Prime Installer Software.