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Power state of RPi and connecting the GPIOs

Posted: Thu Dec 10, 2015 3:18 pm
by linderman
Hello all,

when it is safe to connect GPIOs?

Only when RPi is totally disconnected from power source?

RPi can show only red indicator?

Or the ambitious one - GPIOs can be connected when RPi is fully running?

I want to connect some LEDS and play, but i think it will be too show if after every change in the LEDS, connectors and so on i have to turn off Pi and unplug it from power source , then connect it again and start it...

Thanks

Re: Power state of RPi and connecting the GPIOs

Posted: Thu Dec 10, 2015 3:27 pm
by BMS Doug
Your Pi, Your risk.

I have been known to make connections "on the fly" without powering everything down but I am not to be held responsible if you short together two GPIOs and destroy the SOC.

Re: Power state of RPi and connecting the GPIOs

Posted: Thu Dec 10, 2015 3:29 pm
by FTrevorGowen
linderman wrote:Hello all,
when it is safe to connect GPIOs?
Only when RPi is totally disconnected from power source?
RPi can show only red indicator?
Or the ambitious one - GPIOs can be connected when RPi is fully running?
I want to connect some LEDS and play, but i think it will be too show if after every change in the LEDS, connectors and so on i have to turn off Pi and unplug it from power source , then connect it again and start it...
Thanks
It depends upon your interpretation of "safe" ie. there is greater risk to the Pi than you. It also depends upon how you are (physically) making/breaking the connections. Generally speaking the GPIO's are not "plug'n'play" ie. it's better to plug/unplug (multiple) connections with the Pi powered down - that way you can "double-check" your "new" wiring to make sure that, for example, you haven't connected something providing more than 3.3V to a GPIO pin (which will fry the Pi).
Trev.

Re: Power state of RPi and connecting the GPIOs

Posted: Thu Dec 10, 2015 4:20 pm
by linderman
According to your replies i will always connect/disconnect pins when the RPi is down.

"Down" means also that the power adapter cable is unplugged right?

Re: Power state of RPi and connecting the GPIOs

Posted: Thu Dec 10, 2015 4:30 pm
by FTrevorGowen
linderman wrote: ...
"Down" means also that the power adapter cable is unplugged right?
Easier to have a switch in the uUSB cable (switched off after the software shutdown):
http://www.cpmspectrepi.webspace.virgin ... pterCables
Item "AB" above or "B" here:
http://www.cpmspectrepi.webspace.virgin ... arger.html
Trev.

Re: Power state of RPi and connecting the GPIOs

Posted: Thu Dec 10, 2015 4:43 pm
by linderman
Thank you for your help. "AB" device from above "is a must" for me

Re: Power state of RPi and connecting the GPIOs

Posted: Thu Dec 10, 2015 4:48 pm
by BMS Doug
linderman wrote:Thank you for your help. "AB" device from above "is a must" for me
I made my own.