Intel® Arria® 10 Hard Processor System Technical Reference Manual

ID 683711
Date 8/28/2023
Public
Document Table of Contents

23.3.3. Taking the GPIO Interface Out of Reset

When a cold or warm reset is issued in the HPS, the reset manager resets this module and holds it in reset until software releases it.
  • Cold reset—HPS I/O are in frozen state (tri-state with a weak pull-up). Pin Mux and GPIO/LoanIO Mux are in the default state.
  • Warm reset—HPS I/O retain their configuration. The Pin Mux and GPIO/LoanIO Mux do not change during warm reset, meaning it does not reset to the default/reset value and maintain the current settings. Peripheral IP using the HPS I/O performs proper reset of the signals driving the IO.

After the Cortex*-A9 MPCore* CPU boots, it can deassert the reset signal by clearing the appropriate bits in the reset manager's corresponding reset register. For details about reset registers, refer to "Module Reset Signals".