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Raspberry pi zero

patil.sunny9999

Hello There,

Please help me out. I am using Raspbeery Pi zero and Raspberry pi Zero W. Currently I am working on Serial Transmission on it. First the Serial Transmission was working well on raspberry pi zero. but all of a sudden it stops receiving data.so i checked the TTL voltage level , on RX pin it showing only 0.35 volts. As i checked more i got to know that my RX pin and Ground are shorted. What should i do now ? please suggest.

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  • The raspberry pi and especially the -zero variant is a really simple board. There is not a "serial chip" that this RX pin connects to. The serial lines go directly into the CPU.

     

    It is also extremely unlikely that say a short has developed on the board. So the only thing that seems reasonable is that your CPU has developed a short on the RX pin.

     

    There is only one option  that I can think of that might have caused this: Illegal voltages at the RX pin. These are documented to "reduce reliability a lot", and that's what you seem to be seeing.

     

    The voltage at the RX pin should be between 0 and 3.3V at all times (that's what we mortals are supposed to attempt). The official specs will state something like ABSOLUTE MAXIMUM RATING: min -0.3V max: 3.6V.

     

    So... what are you using to drive the serial signal into the pi? Something that runs at 5V? Or maybe there are long lines between the two devices and some EMC events slowly wear down the pi?

Reply

  • The raspberry pi and especially the -zero variant is a really simple board. There is not a "serial chip" that this RX pin connects to. The serial lines go directly into the CPU.

     

    It is also extremely unlikely that say a short has developed on the board. So the only thing that seems reasonable is that your CPU has developed a short on the RX pin.

     

    There is only one option  that I can think of that might have caused this: Illegal voltages at the RX pin. These are documented to "reduce reliability a lot", and that's what you seem to be seeing.

     

    The voltage at the RX pin should be between 0 and 3.3V at all times (that's what we mortals are supposed to attempt). The official specs will state something like ABSOLUTE MAXIMUM RATING: min -0.3V max: 3.6V.

     

    So... what are you using to drive the serial signal into the pi? Something that runs at 5V? Or maybe there are long lines between the two devices and some EMC events slowly wear down the pi?

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