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Hot!VBUS pin is 5V but the VBUS BITS reads 00 . PIC32MZ2048EFM064

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fravise
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2020/02/04 18:39:26 (permalink)
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VBUS pin is 5V but the VBUS BITS reads 00 . PIC32MZ2048EFM064

Hi Everyone,
I have a board on which I use PIC32MZ as USB HOST, It works okay under normal power ON/OFF conditions. But since the device will be used in scenario where there is lots of power on/off fluctuations there are some worst cases where the USB initialization procedure will freeze at WAIT_FOR_BUS_ENABLE_COMPLETE   at that point the USBOTG VBUS reads 00 instead of 11  while the VBUS pin on oscilloscope reads 5V.
 
I am using Harmony V2.06.
 
I will appreciate any hints to why VBUS pin reads 5V but VBUS register reads 0.
#1

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    nigelwright7557
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    Re: VBUS pin is 5V but the VBUS BITS reads 00 . PIC32MZ2048EFM064 2020/02/04 18:50:22 (permalink)
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    Not sure if it applies to your application but I had some problems with 2.06 and USB.
    Seemed to work ok until I closed down PC end then reopened it and the USB would be hung.
    I was advised to go back to 2.04 and that fixed the problem.
     
     
     
    #2
    mdehaven
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    Re: VBUS pin is 5V but the VBUS BITS reads 00 . PIC32MZ2048EFM064 2020/02/04 19:43:48 (permalink)
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    The analog comparator should read what is on the pin. I had this happen when *another pin* that was 3.3v tolerant was over driven above 3,3. Completely different port was diode clamped from a 6.5v source through a 100k resistor.

    Check all your pins.
    #3
    ric
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    Re: VBUS pin is 5V but the VBUS BITS reads 00 . PIC32MZ2048EFM064 2020/02/04 21:18:17 (permalink)
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    Sanity check.
    Make sure the USB module hasn't been powered down via the USBMD bit.
     

    I also post at: PicForum
    Links to useful PIC information: http://picforum.ric323.co...opic.php?f=59&t=15
    NEW USERS: Posting images, links and code - workaround for restrictions.
    To get a useful answer, always state which PIC you are using!
    #4
    Paul PortSol
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    Re: VBUS pin is 5V but the VBUS BITS reads 00 . PIC32MZ2048EFM064 2020/02/05 07:52:14 (permalink)
    5 (1)
    Ive been using Hv206 for USB Sticks, never lost USB access over all the power cycles.
    Did loose USB access when:
    - Heap was Too small (<10K)
    - Cap on VBUS was too small (using 150uF 6V ceramic, not higher voltage)
    - also recommended to have a 100ohm between PIC VBUS pin and the TPS2051+Connector.
     
    The Hv204 note by nigelwright7557 has been important if communicating to a PC over USB.
    I hadn't seen the 3.3V note before, thank you for posting that mdehaven.
     
    Paul
    #5
    fravise
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    Re: VBUS pin is 5V but the VBUS BITS reads 00 . PIC32MZ2048EFM064 2020/02/11 18:11:05 (permalink)
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    Thanks for the inputs 
    I will do my homework by trying them. Will provide with feedback
    #6
    yts
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    Re: VBUS pin is 5V but the VBUS BITS reads 00 . PIC32MZ2048EFM064 2020/02/14 16:32:31 (permalink)
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    When the rise time of the power supply is long, the reset doesn’t work essentially in case of PIC32MZ2048EFM064. I use a reset IC ( MCP121T-270E/LB(2.63V)) for this PIC.
     
    yts
    #7
    nigelwright7557
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    Re: VBUS pin is 5V but the VBUS BITS reads 00 . PIC32MZ2048EFM064 2020/02/14 19:01:27 (permalink)
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    VBUS is 3v3 in my PIC32 circuit.
    #8
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