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Testing a chip to see if it is fried? — Parallax Forums

Testing a chip to see if it is fried?

mosquito56mosquito56 Posts: 387
edited 2009-03-22 18:36 in General Discussion
·· I purchased a max1270 and cannot get it to work. It is an 7 chan adc. Whenever I connect any voltage to vref or refadj the prop shuts down. At $30 a pop I don't want to order another and fry it to. Is there any way to test this chip or any other chip in general?
·· Yes I've searched the forum with the good search.

· Can anyone recommend a multichannel adc. I found one tlv2534? for $9. I have a 8031 working well but need multiple inputs and don't want to use 3 pins per adc.

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······· "What do you mean, it doesn't have any tubes?"
······· "No such thing as a dumb question" unless it's on the internet
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Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2009-03-21 21:48
    Have you read the datasheet for the MAX1270? The MAX1270 operates off +5V and has +5V logic level outputs and inputs. You've probably damaged your Propeller chip. You don't normally attach external voltages to Vref or refAdj unless you're using an external reference. In that case, you connect refAdj to Vdd (+5V).

    Generally for complex ICs like the MAX1270, the only way to test them is to exercise them in a known good circuit.

    I suggest you go through the Object Exchange to see what ADC drivers exist for multichannel ADCs. I know there's one for the ADC0834 and the ADC0838.
  • Erik FriesenErik Friesen Posts: 1,071
    edited 2009-03-21 22:51
    An mcp3208 works well and there is a stock driver for it.

    Remember that if you want to feed 5 volts to an adc that is fed with 3.3 volts that it will not work because of the protection diodes built in. It will give the 3.3 line a 5v surge.
  • dandreaedandreae Posts: 1,375
    edited 2009-03-22 18:36
    This thread was moved to the "Sandbox" due to content.

    Thanks,

    Dave





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    Dave Andreae

    Parallax Tech Support·
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