Hard Processor System Technical Reference Manual: Agilex™ 5 SoCs

ID 814346
Date 7/19/2024
Public
Document Table of Contents

8.6.2.2. Reset De-assertion Sequence

The reset de-assertion flow has been upgraded to enable any new higher priority reset request that is received to preempt the completion of the flow and return to the HPS idle sequence so that the higher priority reset can be taken.

The following diagram shows the flow for the reset de-assertion sequence.

Figure 271. Reset De-assertion Sequence
  1. De-assert all resets except for the DSU, bridge, peripheral, and individual CPUx warm resets.
  2. At the appropriate time, the power manager requests the reset manager to release all DSU resets so that the default power state can be configured.
  3. The reset manager waits for the SDM to set one or more CPURSTRELEASE[CPUx_RELEASE] bit(s) or the power manager requesting CPUx reset to be released.
  4. The appropriate CPU(s) reset is de-asserted.
  5. After sixteen (16) boot_clk cycles, the reset manager clears any CPURSTRELEASE[CPUx_RELEASE] bit(s) set in the previous step.
  6. The CPUINRESET[CPUx_IN_RESET] bits must be set to indicate which enabled CPUs are still being held in individual core warm reset. This provides you with an indication of the additional CPU resources that are available.
  7. The reset manager continues sequencing other resets.
Note: The assertion of POR immediately causes the state machine to abort this sequence at any step.