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Altera_Forum's avatar
Altera_Forum
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11 years ago

gpio input stuck on high level '1'

HI, i'm make a project using DE0-nano board. in my project i build a uart that recieve a signals from external bluetooth device and translate their ascii code to turn of the leds of the DEO-Nano. i defined one of my gpio as a input pin (GPIO_04) that conected to the blootooth device. the program is not working, and with some checks that i made, i found out that the signal that i get from the gpio is always in high level ('1') even it's doesn't conected to nothing. why is that happen? maby i need to change some settings of the gpio?

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  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    11 years ago

    You can double check the board schematic to see if there is any signal pulling that input pin to high. Also, check the Fitter report to see if it has internal pull up set or tied to vcc?