help in input of atmega 8l

[Ahmet]

  

im a begineer 
i have learn`t to use avr`s outputs (did sum blinking..,patterns,7seg display..etc) 
but its a week now and im not able to read inputs.. 
PLZ HELP 
also tell that can avr detect an output high of 3v..

[GANEEV SINGH]

Hi Ahmet

Make sure that you are defining a particular pin/port as input, also after that declare whether it is pulled up or not. Go as follows:

DDRC & = ~(1<<0);    // defined PORTC's 0 pin as i/p pin

PORTC | = (1<<0);     // declared it as a pulled up i/p pin

Now if you try reading this pin's value it will give you a high state unless any logic 0 is applied to it externally, this is because its pulled up.

This might help, good luck

[Ashutosh Bhatt]

always connect pull up resistor of 1K-10K with ATmega pin when it is used as input

[Author]

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