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Pull up / pull down resistors for the propeller and other ICs ??? — Parallax Forums

Pull up / pull down resistors for the propeller and other ICs ???

Zap-oZap-o Posts: 452
edited 2009-12-21 23:05 in Propeller 1
When using a pull up / pull down resistor for the propeller how do you determine the right size? I know Ohms law but, I guess I am asking if there a specific place I need to look in a data sheet. Also, If I want to use other digital Ic's can I assume the process the same?

Thanks in advance

Comments

  • LeonLeon Posts: 7,620
    edited 2009-12-21 20:49
    It depends on the environment in which the system will be operating, and how much power you can spare. Large values will take less current but be more susceptible to noise.

    Leon

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    Amateur radio callsign: G1HSM
  • Zap-oZap-o Posts: 452
    edited 2009-12-21 21:05
    Leon there has to be a value that I can calculate in the data sheets. Anyone know?
  • LeonLeon Posts: 7,620
    edited 2009-12-21 21:13
    There isn't, I checked in Horowitz and Hill to make sure. 10k is a good value for many applications.

    Leon

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Amateur radio callsign: G1HSM
  • MikeKMikeK Posts: 118
    edited 2009-12-21 23:05
    See the section on Bus Pull-up Resistors in Microchip's app note AN1028
    ww1.microchip.com/downloads/en/AppNotes/01028B.pdf

    I haven't looked at it in a while, but it might be helpful.

    Mike

    Post Edited (MikeK) : 12/21/2009 11:19:02 PM GMT
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