Device Configuration User Guide Agilex™ 3 FPGAs and SoCs

ID 847422
Date 5/23/2025
Public
Document Table of Contents

2.4. Additional Clock Requirements for HPS

The Agilex™ 3 device has specific reference clocks for HPS and HPS EMIF IP. These clock requirements must be met before the FPGA configuration begins.

FPGA Configuration

The Agilex™ 3 device requires additional clocks for HPS and HPS EMIF IP. You must provide a free-running, stable reference clock to these blocks before configuration begins. The clock frequencies must match the frequency settings specified in the Quartus® Prime software during configuration. These reference clocks are in addition to the configuration clock requirements for an internal or external oscillator described in OSC_CLK_1 Requirements.

These blocks and their specific clock names are as listed below.
Table 4.  Additional reference clocks
Block Clock name
HPS reference clock HPS_OSC_CLK 3 4
HPS EMIF pll_ref_clk
Note: The GTS transceiver power supplies VCCEHT_GTS and VCCERT_GTS are required for successful configuration.

Quartus® Prime Pro Edition software allows you to configure the HPS prior to FPGA configuration. To enable this option, select HPS First in the Assignments > Device > Device and Pin Options > Configuration > HPS/FPGA Configuration order dialog box.

HPS First Configuration

Agilex™ 3 devices have the option of booting the HPS before configuring the FPGA core logic. This method is known as the HPS First or HPS Boot First configuration. When you choose this option in the Quartus® Prime Pro Edition software, the following clocks must be operational prior to the FPGA I/O, HPS I/O, and HPS boot, also called a phase 1 configuration.

Table 5.  Verify Clocks are Operational before Phase 1 Configuration
Block Clock name
HPS reference clock HPS_OSC_CLK
HPS EMIF pll_ref_clk

The remaining clocks specified in the FPGA Configuration must be fully operational prior the FPGA core logic configuration, also called phase 2 configuration.

There are additional requirements to ensure HPS Boot First configuration is successful for both phase 1 and phase 2 configuration. For more information about HPS Boot First mode and these requirements, refer to the Hardware Project Compatibility in HPS Boot First Mode section in the Hard Processor System Booting User Guide: Agilex™ 3 SoCs.

3 Only available when HPS is enabled.
4 If you use the FPGA to HPS free clock as the HPS PLL reference clock, the HPS_OSC_CLK clock may not be required.