Arria V Hard Processor System Technical Reference Manual

ID 683011
Date 12/02/2022
Public
Document Table of Contents

A.4.8. Preloader

The function of the preloader is user-defined. However, typical functions include:

  • Initializing the SDRAM interface
  • Configuring the HPS I/O pins
  • Initializing the interface that loads the next stage of software

Initializing the SDRAM allows the preloader to load the next stage of the boot software (that might not fit in the 60 KB available in the on-chip RAM) into SDRAM. A typical next software stage is the open source boot loader, U-boot. The preloader is allowed to load the next boot software stage from any device available to the HPS. Typical sources include the same flash device that contains the preloader, a different flash device, or a communication interface such as an EMAC.