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Hello
I am working with a project using DE1 board. In my project I have to take input from a external circuit of 3.5 v . I use seven segment display to see my output in DE1 board . My verilog coding works well when i use toggle switches as input value. It gives me the output what i desired. But it creates problem when i assign gpio pin as input pin . When i just touch the gpio pin with my hand or connect by a wire with one side open, it gives me the output of logic high value. I set I/O standard as 3.3v LVTTL(default).
Thanks in advance
Biswajit
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I have the same problem, that I get no input from the GPIO pins of the de1. Output is no problem and I can measure the voltage. But when I want to use a gpio pin as input, it is always tied to ground. I tried an external pull-up resistor as well as the internal pull-up resistor, but it doesn't change anything. For testing I use one of the leds for signalling. When I use on of the switches as input everything works fine. Has anyone some idea or had the same problem and solved it?
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When you input a signal from an external circuit, you have to make sure that you unify the ground pins in order to band the logic levels together, so you need to tie the ground of your external circuit with the ground of the DE1 board (you can take it from the GPIO header, I think it's pin number 12... check out the schematics).
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