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I am having this problem in ADC MikroC; Comparission in IF statement is not working

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atifsheikh_91

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Compiler Used = MicroC for PIC
MicroController= Pic16f877a; (and tried other too).

hi all; I am designing a circuit in which ; a potentiometer is used to change the output of Portb; when the voltage is above 2.5 PORTB=1 and when it is low PORTB=0.

Please help me out ; i have chk a simple program with ADC ( given in MICROC) and it is working fine.

code is as

/* task is to make PORTB=1 when read>2.5 and PORTB=0 else; */

// I have tried different program ( without comparassion ) they are working fine
// but this comparission is not doing right operation





void main() {
float read;
ANSEL=0b00000001;
trisa=0xff;
TRISB=0X00;

portb=0x00;


ADC_Init();// ADC initiallized
while(1){

read=ADC_Read(0);
if(read>2.5)
{
portb=0xff;

}
else if(read<2.5)
{
portb=0x00;

}
}




}


Proteus Circuit is attached Capture.PNG


Please help me out
 

read doesn't represent a floating number voltage but a 10bit result .

The ACD result is 0 to 1023 where 0 represents 0 voltage and 1023 the Vref voltage.
To convert the result in voltage you have to use (ADCresult/1023) * Vref but in order to have an accurate result you need to store the result in a float.
An alternative is to multiply the result with 1000 so that the result becomes an integer, ((ADCresult*1000)/1023) * Vref , in that case the result will be in mV
 

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