Reading input pin of pic microcontroller with MIKROC

Question

I need to write a program that will check if an input pin of PIC has a voltage. If a voltage exists then it will give voltage to a selected output pin like PORTB.RB1=1;. Else it will give voltage to other selected output pin like PORTC.RC1=1;.

Is it possible? I have tried to do this, but it does not work .

void main() {

    TRISB=0;
    TRISA=1;
    TRISC=0;

    while(1){
        delay_ms(500);
        // PORTB=0;
        if(PORTA==1){
            PORTB.RB1 =1;
        }
        else{
            PORTC.RC1 =1;
        }
    }
}

Solution

You have not turned off the other port output, and you have not isolated the input pin of PORTA. If it's bit 0 the mask is 1, if it's bit 1 the mask is 2, etc.

void main() {

    TRISB=0;
    TRISA=1;
    TRISC=0;

    while(1){
        delay_ms(500);
        if(PORTA & 1){
            PORTB.RB1 =1;
            PORTC.RC1 =0;
        }
        else{
            PORTB.RB1 =0;
            PORTC.RC1 =1;
        }
    }
}

Comments

[Mushfiqul Tuhin]

thanks for reply . It works , but sorry to say that , I have added a push button to PORTA.RA1 for turning off the voltage of PORTA to see if it works after turning off the voltage . But it acts like first state , it acts perfectly , but dont work after turning off the voltage ( the code as you corrected above , works when I run . But when I disconnect the voltage (by pressing push button )it should turn off " PORTB.RB1 " voltage and turn on the voltage of "PORTC.RC1" . But it dosent . Do you have any solution about that ?

[Weather Vane]

Perhaps the port has a pull-up resistor to stop it floating.

[Mushfiqul Tuhin]

Could you please elaborate it ? When I give voltage to PORTA will it return 1? so that I can check programmatically and do whatever I want after checking PORTA voltage . Input voltage will be turned off or turned on any time by user , using a push button.

[Weather Vane]

I am saying removing an input from the port (leaving it open circuit) won't necessarily make the input go low. If there is a pull-up resistor it will stay high. This is often done to prevent unconnected inputs from floating.

[Mushfiqul Tuhin]

Thank you . actually I was very busy with researching about microcontroller (coz I am new here) . I was googling and working with your corrected code .Though I was delaying But I did not forget to accept your answer . BTW thanks again .

[Weather Vane]

If you want to test the input to a port pin, you must specifically drive it low or high with 0v or +5v, not leave it open circuit.