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jgfoster opened this issue Mar 31, 2021 · 4 comments
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Put string literals in flash memory #72

jgfoster opened this issue Mar 31, 2021 · 4 comments

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@jgfoster
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See the discussion of the F() macro here.
@jgfoster jgfoster added the good first issue Good for newcomers label Apr 13, 2021
eucalvo pushed a commit to eucalvo/TankController that referenced this issue Apr 28, 2021
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docs: add jgfoster as a contributor (Open-Acidification#72)
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@jgfoster
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jgfoster commented May 7, 2021

This may be a bit more complicated since these literals aren't C strings and can't be printed using printf() and friends.

@jgfoster jgfoster removed the good first issue Good for newcomers label Jun 3, 2021
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jgfoster commented Jul 9, 2021

According to this,

Classic AVR architecture is referred as modified Harward, because data and memory are in different address spaces (so address 0 could refer to ram or flash, and there are different functions to access them). New AVR (rebranded megaAVR) architecture is instead more conventional as flash and ram share the same address space (like ARM) so there's no need for special treatment if a variable is only in flash (adding const modifier is enough).

Therefore, "F() is useless in megaAVR architecture."

@jgfoster jgfoster closed this as completed Jul 9, 2021
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It appears that we can recover a substantial amount of memory by using the flash memory for strings. See #249 where we doubled free memory (from 1553 to 3113).

@jgfoster jgfoster reopened this Aug 26, 2021
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Fixed by #251. This gives us over 3000 bytes of free memory.

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