# Arduino Forum

## Using Arduino => Microcontrollers => Topic started by: holmes4 on Oct 15, 2012, 08:56 pm

Title: At what voltage is a digital pin HIGH?
Post by: holmes4 on Oct 15, 2012, 08:56 pm
From the datasheet Section 28.2, for an UNO running at 5V a digital input will read high at a voltage of just 0.6V. Is this correct?.

Mark
Title: Re: At what voltage is a digital pin HIGH?
Post by: Coding Badly on Oct 15, 2012, 09:03 pm
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VCC = 2.4V - 5.5V

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2. "Min." means the lowest value where the pin is guaranteed to be read as high

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Is this correct?

Given the conditions, that's my interpretation.
Title: Re: At what voltage is a digital pin HIGH?
Post by: retrolefty on Oct 15, 2012, 09:14 pm

From the datasheet Section 28.2, for an UNO running at 5V a digital input will read high at a voltage of just 0.6V. Is this correct?.

Mark

No, the spec is saying that the minimum input pin voltage needed to be detected as a HIGH is .6 X Vcc (60% of the actual Vcc voltage being used). So for a 5 volt arduino board the minimum input pin voltage guaranteed to be detected as a HIGH is +3.0 vdc.
For a 3.3vdc powered board the value would be 1.98vdc.
Lefty

Ah, TC beat me to it.  ;)
Title: Re: At what voltage is a digital pin HIGH?
Post by: holmes4 on Oct 15, 2012, 09:20 pm
@retro and TC

now that makes a lot more sense!

Mark
Title: Re: At what voltage is a digital pin HIGH?
Post by: Coding Badly on Oct 15, 2012, 09:35 pm