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[51] AT89C4051 what is the max current it can sink as input

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potatoo

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Hey,

i am a new to microcontrollers and trying to learn about this particular AT89C4051 microcontroller.

Let's say i wanna use PORT 1 as input port. The datasheet says P1.0 and P1.1 don't have internal pullups. I can't find the maximum input-low and input-high current values to apply to port as inputs.

Also it says P1.2-P1.7 has internal pullups. Does it mean that those pins will be read as HIGH if i dont connect anything to these ports? if so, for a LOW input do i only have to connect them to ground?

AT89C4051 Datasheet : http://www.atmel.com/Images/doc1001.pdf
 

Allen6502

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Let's say i wanna use PORT 1 as input port. The datasheet says P1.0 and P1.1 don't have internal pullups. I can't find the maximum input-low and input-high current values to apply to port as inputs.
Used as input, just connect a 10K resistor on each PORT 1.0 and 1.1 as external pullups.

Also it says P1.2-P1.7 has internal pullups. Does it mean that those pins will be read as HIGH if i dont connect anything to these ports? if so, for a LOW input do i only have to connect them to ground?
yes and yes.

Allen
 
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