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### Topic: Max and Min voltage for digital input (Read 6838 times)previous topic - next topic

#### remout

##### Jul 25, 2011, 07:10 pm
What is the Min. voltage to move a pin from low to high?

What is the Max. voltage a digital input pin can take?

Thanks!

#### RuggedCircuits

#1
##### Jul 25, 2011, 07:15 pm
To guarantee that a pin is recognized as HIGH the voltage needs to be at least 3V.

The maximum voltage a pin can take is 5.5V.

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The Ruggeduino: compatible with Arduino UNO, 24V operation, all I/O's fused and protected

#### retrolefty

#2
##### Jul 25, 2011, 08:18 pm
What is the Min. voltage to move a pin from low to high?

From the datasheet: 0.7VCC (2), note 2 = "2. "Min" means the lowest value where the pin is guaranteed to be read as high"  So if the board is power with +5vdc then min high logic voltage input is = +3.5vdc.

What is the Max. voltage a digital input pin can take?

VCC + 0.5, so if chip is powered with +5vdc, max signal input is +5.5vdc.

Lefty

#### RuggedCircuits

#3
##### Jul 25, 2011, 08:28 pm
Quote
From the datasheet: 0.7VCC (2), note 2 = "2. "Min" means the lowest value where the pin is guaranteed to be read as high"  So if the board is power with +5vdc then min high logic voltage input is = +3.5vdc.

From Table 28.2 of the ATmega328P of the datasheet the threshold is 0.6VCC as long as Vcc is in the range 2.4V to 5.5V, which includes the Arduino, so the OP gets to work with the lower threshold 0.6*5V --> 3.0V.

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The Flexible MIDI Shield: MIDI IN/OUT, stacking headers, your choice of I/O pins

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