Problem with reading port of ATMega16

[yas_iiee]

problem reading port

I m facing prob in reading port of avr ATMega16. I wanna check status of PINC bit 0 and I m using following instruction for the purpose:

if( ( PINC & 0x01 ) == 1)
keyg=1;
else
keyg=0;

obviously data direction is set and external pull-ups are used.

the problem is that unless I force all bits of the port high the statement doesnt work and if any bit gets low it works for 'else'.
Complete code is attatched

 

[btbass]

Re: problem reading port

Try reading the port first into a variable then just use the bitwise and.

unsigned char port = PINC;

if(port & 0x01){ 
  keyg = 1;
  } 
else{ 
  keyg = 0;
  }

 

[diegobb]

Re: problem reading port

Can you try the bit_is_set(PORT,PIN) of WinAVR, if you are using WinAVR. In this case it will be:

if (bit_is_set(PINC, PINC0)){
keyg=1;
}else{
keyg=0;
}

If you are not using WinAVR, you can do:

if (PINC & (1<<PINC0)){
keyg=1;
}else{
keyg=0;
}

Yes, this last one is the same code you are using, but who knows, maybe it works.
Do you have the "{" and "}" in your code? Maybe your compiler is not smart enought to realize what you want to do. Try adding the "{" and "}" first.

Regards

 

[yas_iiee]

Re: problem reading port

Try reading the port first into a variable then just use the bitwise and.

unsigned char port = PINC;

if(port & 0x01){ 
  keyg = 1;
  } 
else{ 
  keyg = 0;
  }

I ve tried this as well on the seggustion of my teacher but of no use. The problem still remains

Added after 3 minutes:

Can you try the bit_is_set(PORT,PIN) of WinAVR, if you are using WinAVR. In this case it will be:

if (bit_is_set(PINC, PINC0)){
keyg=1;
}else{
keyg=0;
}

If you are not using WinAVR, you can do:

if (PINC & (1<<PINC0)){
keyg=1;
}else{
keyg=0;
}

Yes, this last one is the same code you are using, but who knows, maybe it works.
Do you have the "{" and "}" in your code? Maybe your compiler is not smart enought to realize what you want to do. Try adding the "{" and "}" first.

Regards

I m using Winavr but the stuff u r reffering needs some header file i guess
Regards

 

[nandhu015]

problem reading port

Here is what you want about bit processing in winavr

https://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&t=91304

Nandhu