Hi,

Testing ADC code in MP lab is this possible??
Don't know it will work but it is according to data sheet ....

#include <htc.h>
__CONFIG(LVP_OFF & BOREN_OFF & PWRTE_ON & WDTE_OFF & FOSC_HS);
#define _XTAL_FREQ 20000000


#define DAD PORTB


main(){
    TRISB=0X00;
TRISA = 0xff ;
ADCON1=0b00000000;
ADCON0=0b10000001;//000 = channel 0, (RA0/AN0)
while(1){
    ADIF=0;
    ADIE=1;
    PEIE=1;
    GIE=1;
    
    __delay_ms(1);
GO_DONE=1;
    __delay_ms(1);

    DAD=ADRESH;
    }
}

It is a very bad program.

1. The initialization is found inside the main loop. Nobody does that.
2. Interrupt is switched on, but no interrupt handler (this was pointed out already).
3. There are unneccessary delays.

OP needs to wait for the A/D like that:

while(!ADIF);

The flag gets set anyway, no matter if you have interrupts enabled.

4. Use MPLAB X + templates. This would save OP from such a bad starter for a program.

 

Then how to make ISR routine any hint????

 

Then how to make ISR routine any hint????

Would it not be an idea to master the more basics details of PIC programming. Before even thinking about using interrupts. You have to learn how to crawl, before you can walk, and walk properly before you can start to run

 

Then how to make ISR routine any hint????

Your focus is to use the ADC. Do that first. Then you can move on to interrupts, if you'd like. For now, remove the enabling of global interrupts and focus on the task at hand.

 

This code is working fine now...!!

2. Interrupt is switched on, but no interrupt handler (this was pointed out already).

How to do this??

while(!ADIF);

not clear to me!!

#include <htc.h>
__CONFIG(LVP_OFF & BOREN_OFF & PWRTE_ON & WDTE_OFF & FOSC_HS);
#define _XTAL_FREQ 20000000


#define DAD PORTB


main(){
    TRISB=0X00;
TRISA = 0xff ;
ADCON1=0b00000000;
ADCON0=0b10000001;//000 = channel 0, (RA0/AN0)
    ADIF=0;
    ADIE=1;
    PEIE=1;
while(1){

    //GIE=1;
    
    __delay_us(10);
GO_DONE=1;
    __delay_us(10);

PORTB=ADRESH;
    }
}

 

This code is working fine now...!!
How to do this??

You do like everyone else does read your datasheet and search for examples. Here is just one

http://forum.allaboutcircuits.com/showthread.php?t=67554


There are many more. This is not an uncommon problem. There are many, many examples an tutorials out there if you just took the time to search.

 

The example was for timer but in ADC i think there is no need of it.....
Actually what is the need of ISR in ADC. if the ADC is working fine without it??

 

This code is working fine now...!!

Excellent! Glad to see you keep at it.

I suggest you start by reading the C compiler manual for interrupts if you want to learn those.

not clear to me!!

while(!ADIF);

ADIF is a flag (single bit) of the PIR register that is set when the A2D completes it's conversion. So the code while(!ADIF) will loop just on that line until ADIF is set, or until the conversion is complete.

Once you detect the conversion is complete you then reset ADIF so it is ready for the next time

But... I wouldn't do it that way. The GO_DONE bit you set to start a conversion is automatically reset when the conversion completes. So if you use:

while(GO_DONE);

you get the same delay for the conversion to complete, and you need not reset the test bit.

ADIF is the Analog to Digital Interrupt Flag and is best for interrupt use... hey, that's what you want to learn, so there's some hints how to make the A2D trigger an interrupt.

 

The example was for timer but in ADC i think there is no need of it.....
Actually what is the need of ISR in ADC. if the ADC is working fine without it??

The only interrupt for ADC would be the interrupt that occurs when the ADC is ready but there is really not a need in most cases.

I believe you can also interrupt when ADC reaches a certain level but that would be through a comparator.

You can use timer interrupts with ADC to read the ADC at regular intervals.

 

OK, i want to connect this to lcd then for that how to convert binary to decimal ASCII??

 

OK, i want to connect this to lcd then for that how to convert binary to decimal ASCII??

Have you sorted out your LCD problems by now?

 

Take a look here.

http://www.asciitable.com/

What does decimal numbers have in common with ASCII numbers?

 

Lots of people don't like using it because it is memory intensive but I use sprintf to make my job easier in writing numbers to the LCD.