F-tile Architecture and PMA and FEC Direct PHY IP User Guide

ID 683872
Date 1/25/2023
Public

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4.5.1. Example of Reference Clock Availability at Device Programming

All enabled system PLLs need to have the Refclk is available at power-on parameter set to the same value. Only the following two situations are supported.
  • All enabled system PLLs have Refclk is available at power-on parameter set to On.
  • Or all enabled system PLLs have Refclk is available at power-on parameter set to Off.
The following examples demonstrate the reference clock behavior during device programming.
In the following example:
Table 97.  Example 1 of System PLL and Reference Clock Availability
System PLL #N Mode of System PLL Refclk is available at power-on
0 Disabled N/A
1 User Configuration On
2 PCIE_FREQ_100 On
  • System PLL #0 is not used.
  • System PLL #1 locks automatically at device programming without the Global Avalon® memory-mapped interface write operations.
  • System PLL #2 locks automatically at device programming without the Global Avalon® memory-mapped interface write operations.
In the following example:
Table 98.  Example 2 of System PLL and Reference Clock Availability
System PLL #N Mode of System PLL Refclk is available at power-on
0 PCIE_FREQ_1000 Off
1 ETHERNET_FREQ_805_156 Off
2 User PCIE-based Configuration Off
  • System PLL #0 does not lock without the Global Avalon® memory-mapped interface write operations.
  • System PLL #1 does not lock without the Global Avalon® memory-mapped interface write operations.
  • System PLL #2 does not lock without the Global Avalon® memory-mapped interface write operations.
  • Device programming takes longer and all channels on this F-tile stay reset until the Global Avalon® memory-mapped interface write operations are completed.