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Applying 9V on Vin, should VDD pin be 5V? — Parallax Forums

Applying 9V on Vin, should VDD pin be 5V?

hottnikks36hottnikks36 Posts: 8
edited 2006-01-09 00:28 in BASIC Stamp
Hello, I have a question regarding powering the BS2p,

i Read somewhere that if i don't have a steady 5V source, i can apply a 6V-12V on the Vin, and internal circuitry will regulate the voltage to 5V.

My question is:

If I apply a 9V voltage on the Vin pin (pin 24), and probe the VDD pin (pin 21) with a voltmeter should it read 5V ?

Simple question, I know, but it seems I can't get my stamp to work, i was wondering if it's busted.

Thanks

Comments

  • Tracy AllenTracy Allen Posts: 6,664
    edited 2006-01-07 18:26
    Yes. The voltage Vdd pin 21 should be 5V, with respect to Vss pin 23. Reset pin 22 will also read 5V.

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    Tracy Allen
    www.emesystems.com
  • allanlane5allanlane5 Posts: 3,815
    edited 2006-01-08 19:20
    Note that the voltage regulator on the BS2 is 'special', in that it can survive having +5 put IN to VDD, OR you can put 6 to 12 volts IN on Vin, and use Vdd as a +5 volt output.

    But yes, when you drive Vin, the Vdd pin should go to +5 out (as compared with Vss, which should be ground).
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-01-09 00:28
    Another thing to consider is that the on-board regulator can only supply about 43 mA of current, so it's not advised to use it for driving anything that would require that kind of current or more.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
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