Hard Processor System Booting User Guide: Agilex™ 5 SoCs

ID 813762
Date 12/20/2024
Public
Document Table of Contents

1.2. Agilex™ 5 SoC FPGA Boot Overview

The Agilex™ 5 SoC FPGA combines an FPGA with a hard processor system (HPS) that is capable of booting operating systems such as Linux* and Zephyr* .

When booting the device from a power-on reset (POR), you can choose between two different methods of booting:
  • FPGA Configuration First Mode— When you select the FPGA First option, the SDM fully configures the FPGA, then configures the HPS SDRAM pins, loads the HPS first-stage bootloader (FSBL) and takes the HPS out of reset.
    Note: The FPGA and all of the I/Os are fully configured before the HPS is released from reset. Thus, when the HPS boots, the FPGA is in user mode and is ready to interact with the HPS.
  • HPS Boot First Mode—When you select the HPS First option, the SDM first configures the HPS SDRAM pins, loads the HPS FSBL and takes the HPS out of reset. Then the HPS configures the FPGA I/O and FPGA fabric at a later time.
    Note: This mode is also referred to as Early I/O Release Mode or Early I/O Configuration. After power-on, the device configures a minimal amount of I/O required by the HPS before releasing the HPS from reset. This mode allows the HPS to boot quickly without having to wait for the full configuration to complete. Subsequently, the HPS may trigger an FPGA configuration request during the SSBL or OS stage.