Intel® Agilex™ Configuration User Guide

ID 683673
Date 1/14/2022

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4.5.2. Preventing Register Initialization During Power-On

If not held in reset, both ALM and Intel® Hyperflex™ registers may lose their initial state if they initialize before their respective source.
You can prevent registers from initializing during power-on by enabling an option in the Intel® Quartus® Prime software. Complete the following steps to turn on this option:
  1. On the Assignments menu select Device > Device and Pin Options > Configuration.
  2. In the Configuration dialog box, turn on Disable Register Power-up Initialization.
    Figure 60. Disabling Register Initialization During Power-On

Coming out of reset, you cannot rely on the value of registers with initial conditions unless you gate your system reset using one of the following options:

  • Designs that include the Reset Release IP must route nINIT_DONE to the system reset.
  • Designs that do not include the Reset Release IP must route INIT_DONE to an external pin and feed INIT_DONE back into the FPGA as an input to system reset.