slimplynth
Posts: 21
Joined: Tue Dec 27, 2011 12:50 am

GPIO state on boot >>> 5v and 3.3V pins

Fri Jun 14, 2013 11:28 am

Apologies if this question has been covered previously, I've tried to search the web/forum but I can't see a similar question.

Before attempting to connect a picaxe (08M2) to the RPi; I thought I'd just double check the voltage pins on the RPi GPIO pins. (3.3V and 5.0V so I don't kill my 08M2)

When I put my multimeter on the 5v + GND pins I read 0V (When RaspBMC is running.)

I thought maybe the GPIO needed to be 'switched on' so I tried the above while running Debian. Doing this also gives 0V but also causes the RPi to reboot.

Is this to be expected? I've tried powering the RPi from a powered USB Hub and Blackberry Phone Charger... same outcome... any ideas what am I doing wrong?

Many Thanks

Lee

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redhawk
Posts: 3465
Joined: Sun Mar 04, 2012 2:13 pm
Location: ::1

Re: GPIO state on boot >>> 5v and 3.3V pins

Fri Jun 14, 2013 11:33 am

The +5v rail is physically connected to the F3 polyfuse so there is no such thing as switching on the GPIO in this case.

Are you sure you're using the correctly pins?? - http://elinux.org/RPi_Low-level_periphe ... .28GPIO.29

I would also double check your multimeter it may require a battery change or there's an intermittent fault with your test leads.

Richard S.

slimplynth
Posts: 21
Joined: Tue Dec 27, 2011 12:50 am

Re: GPIO state on boot >>> 5v and 3.3V pins

Fri Jun 14, 2013 12:16 pm

Cheers Richard, you were spot on with your advice to check the multimeter leads.

They are okay but as soon as I read your post I realised I'd used the 10ADC socket last week, put the probe into the correct socket and all is fine.

(It pains me to publicly admit an incident of stupidity, I'm 100% it won't be the last :D)

Thanks

Lee

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