Arria V Hard Processor System Technical Reference Manual

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

A.4.6. I/O Configuration

The flash devices needed for booting must be connected to specific I/Os. The Boot ROM configures these I/Os depending on the flash device selected by boot select setting. To configure the I/Os, the boot ROM performs pin muxing and pin configuration on these I/Os.

At power up, the dedicated I/O are in tri-state with a weak pull-up until the Boot ROM or preloader configures the I/O. On cold reset, the boot ROM always configures the pin muxes and pin configurations. On warm reset, the user has the capability to specify whether or not the boot ROM code configures the I/Os and pin muxes for boot pins after a warm reset. This configuration on warm reset is enabled by programming the ctrl register in the Boot ROM Code Register group of the System Manager.