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Author Topic: At what voltage is a digital pin HIGH?  (Read 1469 times)
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holmes4
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« on: October 15, 2012, 01:56:14 pm »
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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
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Coding Badly
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« Reply #1 on: October 15, 2012, 02:03:54 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.
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retrolefty
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« Reply #2 on: October 15, 2012, 02:14:27 pm »
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Quote from: holmes4 on October 15, 2012, 01:56:14 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.  smiley-wink
« Last Edit: October 15, 2012, 02:17:18 pm by retrolefty » Logged

holmes4
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« Reply #3 on: October 15, 2012, 02:20:15 pm »
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@retro and TC

now that makes a lot more sense!

Mark
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Coding Badly
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« Reply #4 on: October 15, 2012, 02:35:12 pm »
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Yikes!  Sorry about that.
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retrolefty
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« Reply #5 on: October 15, 2012, 03:12:51 pm »
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Quote from: Coding Badly on October 15, 2012, 02:35:12 pm

Yikes!  Sorry about that.


Well at least you cast your answer as an interpretation, not a fact.  smiley-grin 

Lefty
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