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PDB "Vpp Generation Failed" question — Parallax Forums

PDB "Vpp Generation Failed" question

John CoutureJohn Couture Posts: 370
edited 2008-02-11 21:33 in General Discussion
Before bothering tech support, I figured I'd ask here.

I'm teaching a class using the SX and the Professional Dev Boards.· We seem to be having trouble with a couple of components.

New PDB used by student.· He keeps getting "Vpp Generation Failed".· If I remember correctly from previous discussions, this means that the Key or Blitz cannot get the higher voltage to the chip to erase and program it. Here's what I tried:

1) Numbered the boards so that I can track problems in the future

2) PDB # 8001 give me "Vpp Generation Failed" when used with both an SX-Key (with USB converter) and an SX-Blitz.· Using 4mhz resonator.

I think I have narrowed it down to the PDB because:

3) When I use thet same SX-Key with another board, the key·works fine.

4) When I use the same SX-Key with another board, the blitz works fine.

5) When I changed the power supply from a 7.5Vdc to 9.8Vdc, I still get the Vpp error.

Did I miss something?





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John J. Couture

San Diego Miramar College

Comments

  • dandreaedandreae Posts: 1,375
    edited 2008-02-07 19:54
    Can you add a picture of your set up so that we can see your board?



    Thanks,



    Dave

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    Dave Andreae

    Parallax Tech Support·
  • BeanBean Posts: 8,129
    edited 2008-02-07 20:02
    Did any of the SX pins get bent when inserting it ?

    Try another SX28 chip in the PDB.

    Bean.

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  • John CoutureJohn Couture Posts: 370
    edited 2008-02-07 20:06
    Bean, All pins ok.

    Dave, no setup (i.e. no wires attached), I purposely wanted to try a blank Prof Dev Board so as to not muddy up the problem.

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    John J. Couture

    San Diego Miramar College
  • John CoutureJohn Couture Posts: 370
    edited 2008-02-07 20:11
    Bean, just inserted a new chip. Seems to be ok. Thus, throw out old chip?

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    John J. Couture

    San Diego Miramar College
  • BeanBean Posts: 8,129
    edited 2008-02-08 13:58
    John,
    It would seem that it is toast.

    Instead of throwing it away it might be worth trying to carefully sanding/filing/grinding down the top to expose the die. The students will get a kick out of seeing what is actually inside the chip.

    Bean.

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  • Shawn LoweShawn Lowe Posts: 635
    edited 2008-02-08 18:12
    Thats a good idea, bean!

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    Shawn Lowe


    Maybe I should have waited to do that......
  • John CoutureJohn Couture Posts: 370
    edited 2008-02-11 21:33
    Thanks Bean! Lucky I bought extras!

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    John J. Couture

    San Diego Miramar College
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