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PIC port bits as input

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Naumanpak

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Hi,

I am trying to get my basics right for PIC microcontrollers, before going to interface to a keypad.


I need to know, how can I use a port pin as input. If I take output from an output port pin for eg,

TRISD.RD0=0;// declare output
PORTD.RD0=1//high

and use it as input to an input pin via wiring,

TRISD.RD1=1;//input

I don't get the results on performing any operation?


Please help me out experts!


cheers
 

Hi,

Yes, you can use most i/o pins as Digital Inputs or Digital Outputs in any combination.

You do not specify the chip you are using, but some i/o ports default to Analogue mode and must be Set to Digital mode before the Tris instruction.
The datasheet I/O Ports section details which i/o ports have an Analogue function.
 

    N

    Naumanpak

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Hi, thank you for replying.

Currently I am using pic18f452,

I will check out the datasheet an respond again.


thanks again
 

IF your using a PIC Microcontroller have a look at the ADC section of the Data sheet. For PICs the Special function register to look at is: ADCON1. This regiser selects the pins as analogue or digital.
 

    N

    Naumanpak

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Hi, thanks.

I have been trying for the last two days for nothing.

Can any one of you write me a simple code in c for 18f452 for portd(any 2 bits).

If input at bit7 is 1, bit6 goes high.

I just need to learn how to initialize pins as digital inputs.

I want to interface the keypad later, so I need to get my basics right.


thanks
 

syntax error in ur code.. this is the configuration ...
TRISD0=0; // PORTD pin 0 as OUTPUT

TRISD1=1; // PORTD pin 1 as INPUT...
 

    N

    Naumanpak

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I am using mikroc pic compiler and it works fine with the first syntax.

I need to know the port settings to accept digital input.

ANSEL and ITCON1 etc


thanks

Added after 1 hours 1 minutes:

ok, I have this code now.

It should toggle values of portd with changes in input at portb but.... it doesnt.

But portd remains high.



Code: 
void main()
{
     ADCON1 = 0x0F;          // configure AN pins as digital
     TRISB  = 0xFF;          // set PORTB to be input
     TRISD  = 0x00;
     PORTD=0x00;
     PORTB=0x00;
     while(1)
     {

             if(PORTB==0x00)
             {
                 PORTD=0x00;
             }
             else
             {
                 PORTD=0xFF;
             }
     }
}

Please help me out....!!

Added after 24 minutes:

Hey! thanks all.

I finally got it working!

I wasn't using any pull resistor networks :)


thanks all again!! HELPED


Will you please help me out with this one as well??
 

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