Hard Processor System Technical Reference Manual: Agilex™ 5 SoCs

ID 814346
Date 4/01/2024
Public
Document Table of Contents

5.15.5.3. I/O Control Registers

The HPS provides control registers that allow the system to initialize the following I/O parameters at system startup:

  • Pin assignment for external oscillator clock input
  • Pin assignment for each HPS peripheral
  • HPS peripheral interfaces optionally exposed to FPGA fabric
  • I/O cell configuration
Note: Software can only access the HPS I/O control registers in secure mode.

Control registers can be divided into the following groups:

  • Dedicated pin MUX registers
  • Dedicated configuration registers
  • FPGA access MUX registers
  • HPS JTAG pin MUX register

When you configure the HPS component, Quartus determines the correct register settings, and stores them in the HPS handoff data structure. When the system boots up, the boot loader configures the HPS I/O control registers.