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Altera_Forum's avatar
Altera_Forum
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13 years ago

Storing values as non-volatile in SRAM during RUNTIME

:confused: I am working on a meter based on Cyclone III (using all logic on Quartus and display related using NIOS). i now want to store/change some value during run-time and recollect on consequent...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
13 years ago

If you might have to save multiple items something a little more complex is worth the effort.

I used a 24bit 'tag' and 8 bit 'length' in one 32bit word, followed by 'length' data words.

Update sequence:

1) Find the end and write in the new length (leaving the tag 0xffffff)

2) Write in the new data.

3) Modify the new tag.

4) Change the old tag to zero.

That will survive most interrupted write sequences.