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Re: Going to use gpio for the first time

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Michael Schwingen <news-1513678000@discworld.dascon.de> writes:

> On 2026-04-21, Daniel <me@sc1f1dan.com> wrote:
>> Are there any newbie things I should look out for while I dive in?
>> I'll be doing all the work on my trusty stock pi500.
>
> Be careful about different voltage levels. The atmega *can* run on 5V, while
> the raspberry's GPIO pins only tolerate 3.3V.
>
> If you run the atmega from 3.3V too (ideally sourced from the pi, so they
> come up at the same time), you have fewer problems.

Still haven't initiated planning or coding yet. It's a crazy sports time
for me with basketball playoffs and regular season baseball in full
swing.

Off the top of my head I don't intend on using gpio power. I figure the
atmega could be powered by the bench power supply. The data line could
get a diode, now that you mention the risk of voltage backfeed to
gpio. That, or disconnect the wire between programming steps. And
connect atmega and breadboard ground to gpio ground.

Lacking an EE degree, learning all this magic has been a blast.

Of course, that's just off the top of my head. The pi500 has a different
pinout from other rpi models based on the few bits I've seen in the pdf
guide. I have the gpio extender being shipped and the pinout guide
thingamabob for reference.

--
Daniel
sysop  | air & wave bbs
finger | calcmandan@bbs.erb.pw

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Going to use gpio for the first time Daniel <me@sc1f1dan.com> - 2026-04-21 09:53 -0700
  Re: Going to use gpio for the first time rbowman <bowman@montana.com> - 2026-04-22 00:54 +0000
    Re: Going to use gpio for the first time Daniel <me@sc1f1dan.com> - 2026-04-22 07:09 -0700
  Re: Going to use gpio for the first time Michael Schwingen <news-1513678000@discworld.dascon.de> - 2026-04-22 16:08 +0000
    Re: Going to use gpio for the first time The Natural Philosopher <tnp@invalid.invalid> - 2026-04-22 20:40 +0100
      Re: Going to use gpio for the first time druck <news@druck.org.uk> - 2026-04-22 21:09 +0100
        Re: Going to use gpio for the first time The Natural Philosopher <tnp@invalid.invalid> - 2026-04-22 21:13 +0100
          Re: Going to use gpio for the first time Theo <theom+news@chiark.greenend.org.uk> - 2026-04-22 23:45 +0100
            Re: Going to use gpio for the first time The Natural Philosopher <tnp@invalid.invalid> - 2026-04-23 09:58 +0100
          Re: Going to use gpio for the first time not@telling.you.invalid (Computer Nerd Kev) - 2026-04-25 08:33 +1000
    Re: Going to use gpio for the first time Daniel <me@sc1f1dan.com> - 2026-04-22 23:55 -0700
      Re: Going to use gpio for the first time rbowman <bowman@montana.com> - 2026-04-23 18:35 +0000
  Re: Going to use gpio for the first time Gordon Henderson <gordon+usenet@drogon.net> - 2026-04-23 12:36 +0000

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