# Digital I/O

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## 6501 digital input levels

Hello,

I am using 6501 port 1 to read digital logic of my circuit output.  In 6501  port pins  have +5V and 4.7K pull-up resistors. Up to what voltage on the port pin (configured as digital input), 6501 declare as LOW and  HIGH?. I read elsewhere that voltage between 0 to 0.8V will be  reported as logic 0 and voltage above 2V will be reported as  Logic high. Is this correct?

Thanks,

Leyo Joseph

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## Re: 6501 digital input levels

When in doubt, read the scpecifications: USB-6501 Specifications

@LeyoJoseph wrote:

I read elsewhere that voltage between 0 to 0.8V will be  reported as logic 0 and voltage above 2V will be reported as  Logic high. Is this correct?

After reading the specifications...Yes, that is correct.  Those are fairly standard voltages for TTL.

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## Re: 6501 digital input levels

Thanks.

One more question  on this, please. I think there is a way to change the +5V operation top +3.3V by setting some parameters of 6501. How to do this?

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## Re: 6501 digital input levels

@LeyoJoseph wrote:

I think there is a way to change the +5V operation top +3.3V by setting some parameters of 6501. How to do this?

As an input, it will accept 3.3V levels.  But as an output, it will use 5V levels.  You can use a level shifting circuit to change logic levels, for example a SN74LVCC4245APWR.

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