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Can i program MCu GPIO to be in Hi-z ?

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levnu

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Can i program the MCu GPIO output to '1' or 'Open circuit/Hi-Z/tri state'?

i thought that GPIO is sort of Open drain so how can it be Hi-Z?

Also i still couldn't understand how Hi-z is achived, is it only a FET switch?
 

Are you referring to a specific mcu?

There are mcu with open drain output or push-pull or others have a selection flag to make a pin open drain.
 
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    levnu

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No i asked in general.
i'm tring to understand how GPIO implemented in mcus & if also some mcu includes Hi-Z option in GPIO, so how it can be acheived?
 

levnu said:
No i asked in general.
i'm tring to understand how GPIO implemented in mcus & if also some mcu includes Hi-Z option in GPIO, so how it can be acheived? QUOTE]


Is this a college/university assignment i.e. is this your homework?

Either way, I think you need to do some fundamental digital electronics reading. Make sure you understand the TTL 'push-pull' logic output. From there you can read and understand open-drain and tri-state. Trying to teach you that here is not what the forum's aiming for.

Either way, the usual method to get a GPIO pin into high-impedance mode is to configure it as an input and ignore it in software.

However, if it's a true 8051 or similar, you configure a pin to be an input by writing a '1' to it's output register then leaving it alone. These MCUs implement 'quasi-bidirectional' GPIO pins which was a scheme that saved MCU logic gates by eliminating configuration registers etc back when every gate was precious.

Please do the reading, it's the best way. Good luck...
Click to expand...
 
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Thanks, it seems you trying to prevent me from asking whatever i see is right...it doesn't importent what is my reason for asking.....you had the choise not to answer and even not continue reading...
i'm autodidact and i try to find leads to info that interests me ...

if wouldn't ask this question here i could continue swimming in the ocean of endless knowlage w/o being refered by you to TTL 'push pull' logic output etc.

Moreover this forum is great!!!
and if i ever have enought knowlage to answer to others i'll defiently do it, although my own knowlage is limited so for now i only asking question in this forum.

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TonyM, what the forum's aiming for?
 

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