gdb stm32 peek & poke

Pošto smo uspešno povezali razvojnu pločicu, da probamo da upalimo LED diodu na pločici.

Kod je preuzet iz https://github.com/satoshinm/pill_blink bare-metal/pill_blink.c

Pošto nam st-util prepoznaje pločicu, povezaćemo se gdb-om.

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$ arm-none-eabi-gdb -ex 'target extended-remote localhost:4242'
GNU gdb (GDB) 8.1
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License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
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and "show warranty" for details.
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Type "show configuration" for configuration details.
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Remote debugging using localhost:4242
warning: No executable has been specified and target does not support
determining executable automatically.  Try using the "file" command.
0xfffffffe in ?? ()
(gdb)

Zatim uraditi potrebnu inicijalizaciju, u ovom trenutku nemam pojma šta ovo tačno radi, prepisano je iz pill_blink primera.

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set *(unsigned int *)0x40021018 |= (1 << 4)
set *(unsigned int *)0x40011004 |= (0x00 << (((13 - 8) * 4) + 2))
set *(unsigned int *)0x40011004 |= (0x02 << ((13 - 8) * 4))

Po ovome LED na pločici ce početi da svetli. Da bi ga ugasili treba da izvšimo:

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set *(unsigned int *)0x40011010 = (1 << 13)

I potom da upalimo:

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set *(unsigned int *)0x40011014 = (1 << 13)

Kao u stara dobra vremena 8bitnih računara, osim što sve deluje malo komplikovanije.