Message-ID: <69ebefce@news.ausics.net> From: not@telling.you.invalid (Computer Nerd Kev) Subject: Re: Going to use gpio for the first time Newsgroups: comp.sys.raspberry-pi References: <877bq02r1o.fsf@rpi3> <10sb88a$2gl78$2@dont-email.me> <10sb9ul$2h0sl$1@druck.eternal-september.org> <10sba51$2h3ih$1@dont-email.me> User-Agent: tin/2.6.5-20251224 ("Glenury") (Linux/2.4.31 (i586)) NNTP-Posting-Host: news.ausics.net Date: 25 Apr 2026 08:33:50 +1000 Organization: Ausics - https://newsgroups.ausics.net Lines: 31 X-Complaints: abuse@ausics.net Path: csiph.com!news.bbs.nz!news.ausics.net!not-for-mail Xref: csiph.com comp.sys.raspberry-pi:37940 The Natural Philosopher wrote: > On 22/04/2026 21:09, druck wrote: >> On 22/04/2026 20:40, The Natural Philosopher wrote: >>> On 22/04/2026 17:08, Michael Schwingen wrote: >>>> On 2026-04-21, Daniel 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. >>>> >>> In theory., In practice they can tolerate 5V if not from an uber low >>> impedance source >> >> To avoid tears before bedtime, it is best to disregarded that. > > *shrug.* been running that way for some time It'll have protection diodes that limit the voltage at the inputs to less than the 3.3V supply. However they're not designed to be used in normal operation so the extra current carried from them on the power connections inside the chip might upset the voltage to other parts and cause weird problems, eg. when lots of inputs go to 5v. So it could be a source of very confusing behaviour and possible damage, though it's probably a small risk if there are just a few high-impedance 5V signals connected. -- __ __ #_ < |\| |< _#