AN 709: HPS SoC Boot Guide - Cyclone V SoC Development Kit

ID 683265
Date 1/27/2016
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1.2.2.6. Boot from RAM on Warm Reset

This scenario applies only for Warm resets. The Boot ROM can be instructed to directly jump to an image already loaded in OCRAM with an optional CRC check for that image.

The following registers located in sysmgr (romcodegrp and warmramgrp) are used to set up the Boot from RAM on Warm Reset:

  • enable - Set bit 0 to enable Boot from RAM on Warm reset.
  • datastart - Byte offset in OCRAM for the region to be CRC-validated. Needs to be 4 byte aligned.
  • length - Size of OCRAM area to be CRC-validated, in 4 byte words. Set to 0 to disable the CRC validation.
  • execution - Byte offset in OCRAM where to jump to.
  • crc - CRC value for the OCRAM area that is CRC-validated.
Note: When booting from RAM, the Boot ROM does not do any initialization, including clocking and it therefore ignores the CSEL pins.