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Altera_Forum
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19 years ago

Booting Nios2 from custom NV-RAM

I tried this question on comp.arch.fpga newsgroup - no answer. Here is probably a better place to ask. Preface: When the Nios2 CPU reset vector points into Altera-provided CFI flash the SOPC ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
19 years ago

If you are using NVRAM instead of Flash you may place the component into SOPC builder as a normal RAM memory (the IDT SRAM for example). You will get a warning that the reset and exception address is pointing to a volatile memory, but you can ignore it.

Than instead of writing the code into Flash, just download (Run) it into NVRAM. The code should stay there after a power up sequence. In the properties dialog for the project library you van select which part of the code should be placed into NVRAM (only .text or variables too, the stack? ...).

If you would like to automate the process, subversion friendly, than modify the flash programmer script to use the nios2-download executable instead of the flash programmer.

You may have to add some format conversions if you would like to use the Altera provided boot loader.

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