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USB is Not Connecting — Parallax Forums

USB is Not Connecting

karlprescottkarlprescott Posts: 15
edited 2016-06-23 14:25 in General Discussion
Whilst programming my Propeller P8X32A-Q44 I have declared ports 30 & 31 and now can't connect using USB as I wrote the code to EEPROM so when it starts up it runs the code that is stopping USB communication.

Is there a way to clear the EEPROM (Allowing me to rewrite correct code)?

Comments

  • kwinnkwinn Posts: 8,697
    Download some other code. The download program resets the propeller and the rom code downloads the new code and writes it to eeprom if desired.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    kwinn,

    I think he's saying he can't connect to update the program.

    My suggestion would be to connect the board to USB with the power off.
  • karlprescottkarlprescott Posts: 15
    You are right. I now can't update the program. Tried reprogramming with power off on USB and that does not even light up. Think we have blown the USB chip
  • MikeDYurMikeDYur Posts: 2,176
    I'm probably dumb but, if he repurposed the USB pins in his program, don't he just have to be quick enough to load a new program into EEPROM after turning the power on.
  • kwinnkwinn Posts: 8,697
    karlprescott wrote: »
    You are right. I now can't update the program. Tried reprogramming with power off on USB and that does not even light up. Think we have blown the USB chip

    You should be able to use a terminal emulator to do a loopback test on the USB chip by putting a jumper between Rx and Tx.
  • ElectrodudeElectrodude Posts: 1,657
    edited 2016-06-24 15:00
    kwinn wrote: »
    karlprescott wrote: »
    You are right. I now can't update the program. Tried reprogramming with power off on USB and that does not even light up. Think we have blown the USB chip

    You should be able to use a terminal emulator to do a loopback test on the USB chip by putting a jumper between Rx and Tx.

    Also, if the Prop is doing IO on the Rx and Tx lines, you should probably hold the Propeller in reset by manually holding down its reset button (or by shorting its reset pin to ground) while doing this, so the USB chip doesn't fight the Propeller.

    EDIT: This is assuming you have an onboard USB chip.
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