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Active high or active low. — Parallax Forums

Active high or active low.

WebheadFredWebheadFred Posts: 27
edited 2010-10-27 13:18 in Propeller 1
Greetings,
In my project, I'm using a cog to monitor a push button and take action/modify variables in the main program. I am able to use either an active high or active low. Is there any real advantage or disadvantage to one over the other in this simple input?

Regards,
Fred

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2010-10-27 11:33
    With active high switches, you need to run Vdd to where the switches are which may or may not be convenient. With active low switches, you need to run Vss to the switches which you are likely to have there anyway. That's probably the main distinction.
  • WebheadFredWebheadFred Posts: 27
    edited 2010-10-27 11:44
    Thanks Mike.
    I'm about to finish my first real project and it's all self contained. I was wondering if the active high (it wired this way now) took any more battery power than the active low as far as longevity.

    Best Regards,
    Fred
  • kwinnkwinn Posts: 8,697
    edited 2010-10-27 13:18
    Power use should be the same if you use pullups for active low and pulldowns for active high.
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