konagold7
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Accidently plugged TTl into wrong pins

Thu Jan 07, 2016 5:23 am

help! :oops: I received my raspberry B+ today and immediately tried to plug it into my laptop. I was not aware at the time that the serial cables had a set pin. After a few moments being plugged in, the usb end was really hot to the point of when I pulled the usb out I left an indent where my thumb was at. Now when I plug in TTL cable I get a message saying that the usb device is malfunctioned but the leds on the pi still turn on. Do I need to get a new TTL cable, or did I completely fry my pi and get a new one :( ?



[/lol fry my piei] :lol:

klricks
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Re: Accidently plugged TTl into wrong pins

Thu Jan 07, 2016 8:33 am

konagold7 wrote:..... I was not aware at the time that the serial cables had a set pin. .......... I plug in TTL cable .....:
Not sure what you mean? .... What TTL cable? Link?

Plug in other USB devices such as keyboard and mouse into the same port. If it works then the RPi is probably OK........ If not and/or any part of the RPi gets really hot then time to buy a new RPi.
Unless specified otherwise my response is based on the latest and fully updated RPiOS Buster w/ Desktop OS.

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RaTTuS
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Re: Accidently plugged TTl into wrong pins

Thu Jan 07, 2016 8:44 am

I'm guessing here as you have only provided scant info
if you have plugged a 5V or more serial interface into the RPi you will have cabbaged something seriously
the GPIO pins on the RPI are 3.3V only

what where you attempting to plug into where ?

you can possibly power the RPi from a laptop usb but it's not recommended
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konagold7
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Re: Accidently plugged TTl into wrong pins

Mon Jan 11, 2016 11:51 am

klricks wrote:
konagold7 wrote:..... I was not aware at the time that the serial cables had a set pin. .......... I plug in TTL cable .....:
Not sure what you mean? .... What TTL cable? Link?

This cable https://www.adafruit.com/products/954
using this picture as reference http://grimbodroid.blogspot.com/2012/08 ... ges-1.html
I plugged the black ground wire into the 2 pin, the white wire into the 4 pin, and the green wire into the 6 pin. I hope that adds a little clarity to my question.

AndyPi
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Re: Accidently plugged TTl into wrong pins

Mon Jan 11, 2016 12:23 pm

Bit unsure about your pin numbering but see https://learn.adafruit.com/adafruits-ra ... t-the-lead

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Burngate
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Re: Accidently plugged TTl into wrong pins

Mon Jan 11, 2016 5:12 pm

Black wire (0v out of USB dongle) into Pi's pin 2 (Pi's+5v)
White wire (Rx into dongle) into Pi's pin 4 (also Pi's +5v)
Green wire (Tx out of dongle) into Pi's pin 6 (Pi's ground)

So your Pi probably survived, though the polyfuse may have tripped - if so, waiting for 24hrs will cure that.

You put -5v up the dongle's output. It's toast.

Since your laptop and your Pi's power supply are both floating - their grounds aren't connected to Earth - connecting the ground of one to the +5v of the other won't cause a problem.
Also connecting the dongle's input to the same point - Pi's 5v and laptop's ground won't hurt - it's designed to have that happen when data's flowing down it.
But the green wire, Tx out of the dongle, expects to see positive voltages, not negative.

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