[SOLVED] problem in reading multiple adc channels

vinay bs · May 22, 2012

Hi,

i am new to micro controllers programming, and i stuck up in the middle of code, the problem i am facing is, i can read the data when i tried using single
adc channel, but i am not able to read data while using two adc channels,i am using pic16f676 microcontroller and hi tech c compiler for compilation..
when i debug the program using mplab sim the program works perfectly but failing to get the data from pins in the circuit...

please help me to continue

thanks

ud23 · May 22, 2012

post your hardware schematic also

vinay bs · May 22, 2012

hi,
i attached simple hardware schematic here, p.f.a

using ldr for input(solar sense) and variable dc for olsense..

using leds to check the output(load,spulse, solarled)

ud23 · May 22, 2012

vinay bs said:
View attachment 74691

hi,
i attached simple hardware schematic here, p.f.a

using ldr for input(solar sense) and variable dc for olsense..

using leds to check the output(load,spulse, solarled)

ok did you checked adc channel 1 separately? i guess you having adc channel 1 problem. did you check voltage on your that particular channel?
your schematic don't helpful.

i suggest if you have simulator try simulation your code.

vinay bs · May 22, 2012

actually i tried with single adc channel(solar sense).... it worked good....
in the same lines i tried to implement another channel using loop technique....
then checked voltage on first channel .... no use not getting any voltage...
i did circus in all the directions but no use....
did u cheked my code???

ud23 · May 22, 2012

I checked your code but not in detail though you just try swapping adc channels just for debugging i mean in your code use adc channel 1 in place of adc channel 0 so if your channel 1 sensor faulty then you can fix that

Surender Reddy · May 22, 2012

give some delay after reading one adc, then go for second one...
try for it , hope it works....

vinay bs · May 22, 2012

tried swapping channels, even by giving 1m sec delay....
not working in any ways....
atleast if i got to know algorithm to access 2 or more channels it may be help full....

ud23 · May 22, 2012

https://www.microchipc.com/sourcecode/
https://www.electro-tech-online.com...ny-sample-program-htc-pro-adc-pic16f877a.html
try this sites

vinay bs · May 22, 2012

thanks ud23 for the links...
but all examples they have given is for single adc channel.....

ud23 · May 22, 2012

Do it like this:

1. Set the desired channel.
2. Wait for 20 us.
3. Read the ADC.
4. Do the calculations.

The same steps are required for each channel.
Do it in a for(;

loop.

engshahrul · May 22, 2012

Put some delay about 2ms between analog channel transition.

internetuser2k11 · May 23, 2012

Try this.

Code:

[syntax = c]

//Overload, Dusk and Dawn Control
#include<htc.h>
#include<stdlib.h>
#include<stdio.h>
__CONFIG(FOSC_INTRCCLK&PWRTE_ON&BOREN_OFF&WDTE_OFF);
#define load PORTBbits.RB3
#define spulse PORTBbits.RB2
#define solarled PORTBbits.RB6
#define solarsense PORTAbits.RA0
#define olsense PORTAbits.RA1

unsigned long int analogchannel(unsigned int i)
{
	unsigned short int hbyte,lbyte,adcout;
        ADON = 1;
        GODONE = 1;
	switch(i)
	{
		case'0':
		ADCON0=0x81;
		while(GODONE);
                ADON = 0
                return ADRES;
                break;
		case'1':	
 		ADCON0=0x85;
                while(GODONE);
                ADON = 0
                return ADRES;
		break;
	}

	
}

void main(void)
{
unsigned long int ssvalue,olvalue;
unsigned long int lon_value=409;//(for 2V)
unsigned long int htvalue=665;//(for 3.25V)
unsigned long int ltvalue=563;//(for 2.75)
unsigned long int olvoltage=819;//(for 4V)
TRISBbits. TRISB2=0;//spulse
TRISBbits. TRISB6=0;//solarled
TRISBbits. TRISB3=0;//load
TRISAbits. TRISA1=1;//ol sense
TRISAbits. TRISA0=1;//solar sense
ANSEL = 0x03;
ADCON1=0x00;

	while(1)
	{
		solarled=1;//led ON to show uc working
		ssvalue=analogchannel(0);
		if(ssvalue >= ltvalue && ssvalue <= htvalue)
		{
			msdelay(5);
			if(ssvalue >= ltvalue && ssvalue <= htvalue)
			{
				spulse=1;
			}     	 
		}
		else
		spulse=0;

		if(ssvalue <= lon_value)
		{
			msdelay(5);
			if(ssvalue <= lon_value)
			{
				load=1;//light on
			}
		}	
		else
		load=0;//light off
		
		olvalue=analogchannel(1);
		if(olvalue >= olvoltage)
		{
			msdelay(5);
			if(olvalue >= olvoltage)
			{
				load=0;//light off
			}	
		}
		
	}
}

void msdelay(unsigned int time)
{
unsigned char i,j;
	for(i=0;i<time;i++)			
		for(j=0;j<165;j++);
}



[syntax]

Are you sure that passing arg to function uses single quotes?

Code:

[syntax = c]

ssvalue=analogchannel('0');
olvalue=analogchannel('1');

[/syntax]

Or is it

Code:

[syntax = c]

ssvalue=analogchannel(0);
olvalue=analogchannel(1);

[/syntax]

---------- Post added at 07:22 ---------- Previous post was at 06:52 ----------

Are you sure it is giving values for channel 1? Because you have not used hbyte,lbyte,adcout anywhere in your code. How can analogchannel(); return adcout when there is no code written for finding the value of adcout. Isn't there library for adc in htc?

---------- Post added at 07:52 ---------- Previous post was at 07:22 ----------

There is no algorithm to access 2 or more channels. You have to select a channel, then read the channel and assign the return value of some raed_adc(); function to some float variable. like.

float channel1_val, channel2_val;

channel1_val = read_adc(0);
channel2_val = read_adc(1);
.............
channeln_val = read_adc(n-1);

Do you know the what is the function used to read adc channels in htc?

vinay bs · May 23, 2012

//Overload, Dusk and Dawn Control
#include<htc.h>
#include<stdlib.h>
#include<stdio.h>
__CONFIG(FOSC_INTRCCLK&PWRTE_ON&BOREN_OFF&WDTE_OFF);
#define load PORTCbits.RC3
#define olsense PORTAbits.RA0
#define spulse PORTAbits.RA5
#define solarled PORTCbits.RC4
#define solarsense PORTCbits.RC2
void msdelay(unsigned int);

unsigned int oadc(unsigned char osource)
{
unsigned short int hbyteo,lbyteo,adcouto;
switch(osource)
{
case'o':
ADCON0=0x80;
ADCON1=0x10;
ANSEL=0x01;
TRISAbits. TRISA0=1;
}
msdelay(1);
ADCON0bits.ADON=1;
ADCON0bits.GO=1;
while(ADCON0bits.nDONE==1);
hbyteo=ADRESH;
lbyteo=ADRESL;
adcouto=lbyteo|(hbyteo<<8);
return adcouto;
}

unsigned int sadc(unsigned char ssource)
{
unsigned short int hbytes,lbytes,adcouts;
switch(ssource)
{
case's':
ADCON0=0x98;
ADCON1=0x10;
ANSEL=0x40;
TRISCbits. TRISC2=1;
}
msdelay(1);
ADCON0bits.ADON=1;
ADCON0bits.GO=1;
while(ADCON0bits.nDONE==1);
hbytes=ADRESH;
lbytes=ADRESL;
adcouts=lbytes|(hbytes<<8);
return adcouts;
}

//#pragma psect code main=0x100
void main(void)
{
unsigned short int ssvalue,olvalue;
unsigned short int lon_value=409;//(for 2V)
unsigned short int htvalue=665;//(for 3.25V)
unsigned short int ltvalue=563;//(for 2.75)
unsigned short int olvoltage=819;//(for 4V)
TRISAbits. TRISA5=0;//spulse
TRISCbits. TRISC4=0;//solarled
TRISCbits. TRISC2=1;//solar sense
TRISCbits. TRISC3=0;//load
TRISAbits. TRISA0=1;//ol sense

while(1)
{
solarled=1;//led ON to show uc working
ssvalue=sadc('s');
if(ssvalue >= ltvalue && ssvalue <= htvalue)
{
msdelay(5);
if(ssvalue >= ltvalue && ssvalue <= htvalue)
{
spulse=1;
}
}
else
spulse=0;

if(ssvalue <= lon_value)
{
msdelay(5);
if(ssvalue <= lon_value)
{
load=1;//light on
}
}
else
load=0;//light off

olvalue=oadc('o');
if(olvalue >= olvoltage)
{
msdelay(5);
if(olvalue >= olvoltage)
{
load=0;//light off
}
}

}
}

void msdelay(unsigned int time)
{
unsigned char i,j;
for(i=0;i<time;i++)
for(j=0;j<165;j++)
}

---------- Post added at 09:35 ---------- Previous post was at 09:32 ----------

this is my actual code.....

---------- Post added at 09:36 ---------- Previous post was at 09:35 ----------

please check the above code and let me know if any mistakes.....

---------- Post added at 09:45 ---------- Previous post was at 09:36 ----------

sorry no library function to read adc in htc :-(

internetuser2k11 · May 23, 2012

OK. I'll check your code. But is there a function read_adc(); in htc?

internetuser2k11 · May 23, 2012

Did you try this code?

Code:

[syntax = c]

//Overload, Dusk and Dawn Control
#include<htc.h>
#include<stdlib.h>
#include<stdio.h>
__CONFIG(FOSC_INTRCCLK&PWRTE_ON&BOREN_OFF&WDTE_OFF);
#define load PORTBbits.RB3
#define spulse PORTBbits.RB2
#define solarled PORTBbits.RB6
#define solarsense PORTAbits.RA0
#define olsense PORTAbits.RA1

unsigned long int analogchannel(unsigned int i)
{
	unsigned short int hbyte,lbyte,adcout;
        ADON = 1;
        GODONE = 1;
	switch(i)
	{
		case'0':
		ADCON0=0x81;
		break;

		case'1':	
 		ADCON0=0x85;
                break;
	}

        while(GODONE);
        ADON = 0
        return ADRES;

	
}

void main(void)
{
unsigned long int ssvalue,olvalue;
unsigned long int lon_value=409;//(for 2V)
unsigned long int htvalue=665;//(for 3.25V)
unsigned long int ltvalue=563;//(for 2.75)
unsigned long int olvoltage=819;//(for 4V)
TRISBbits. TRISB2=0;//spulse
TRISBbits. TRISB6=0;//solarled
TRISBbits. TRISB3=0;//load
TRISAbits. TRISA1=1;//ol sense
TRISAbits. TRISA0=1;//solar sense
ANSEL = 0x03;
ADCON1=0x00;

	while(1)
	{
		solarled=1;//led ON to show uc working
		ssvalue=analogchannel(0);
		if(ssvalue >= ltvalue && ssvalue <= htvalue)
		{
			msdelay(5);
			if(ssvalue >= ltvalue && ssvalue <= htvalue)
			{
				spulse=1;
			}     	 
		}
		else
		spulse=0;

		if(ssvalue <= lon_value)
		{
			msdelay(5);
			if(ssvalue <= lon_value)
			{
				load=1;//light on
			}
		}	
		else
		load=0;//light off
		
		olvalue=analogchannel(1);
		if(olvalue >= olvoltage)
		{
			msdelay(5);
			if(olvalue >= olvoltage)
			{
				load=0;//light off
			}	
		}
		
	}
}

void msdelay(unsigned int time)
{
unsigned char i,j;
	for(i=0;i<time;i++)			
		for(j=0;j<165;j++);
}



[syntax]

---------- Post added at 10:19 ---------- Previous post was at 10:02 ----------

In you code

Code:

olvalue=oadc('o');
ssvalue=sadc('s');

You've not initialized olvalue and ssvalue.

vinay bs · May 23, 2012

no library functions provided by htc for adc...

internetuser2k11 · May 23, 2012

Try this

In the code I've given, use ADCON0 = 80; and ADCON0 = 84; For ADCON1 you have to mention your Fosc. What is your Fosc?

ud23 · May 23, 2012

https://extremeelectronics.co.in/mi...tal-converter-–-pic-microcontroller-tutorial/

try this adc routines its give you idea how use two channels adcs they using adc channel selection and you using switch case in your code i guess

Code:

unsigned int analogchannel(unsigned int i)
{
	unsigned short int hbyte,lbyte,adcout;
	switch(i)
	{
		case'0':
		ADCON0=0x41;
		ADCON1=0x00;
        break;
		case'1':	
 		ADCON0=0x49;
		ADCON1=0x00;
		break;
	}

	
}

internetuser2k11 · May 23, 2012

Try this

Code:

[syntax = c]

//Overload, Dusk and Dawn Control
#include<htc.h>
#include<stdlib.h>
#include<stdio.h>
__CONFIG(FOSC_INTRCCLK&PWRTE_ON&BOREN_OFF&WDTE_OFF);
#define load PORTBbits.RB3
#define spulse PORTBbits.RB2
#define solarled PORTBbits.RB6
#define solarsense PORTAbits.RA0
#define olsense PORTAbits.RA1

unsigned long int analogchannel(unsigned int i)
{
	unsigned short int hbyte,lbyte,adcout;
        ADON = 1;
        GODONE = 1;
	switch(i)
	{
		case'0':
		ADCON0=0x80;
		break;

		case'1':	
 		ADCON0=0x84;
                break;
	}

        while(GODONE);
        ADON = 0
        return ADRES;

	
}

void main(void)
{
unsigned long int ssvalue,olvalue;
unsigned long int lon_value=409;//(for 2V)
unsigned long int htvalue=665;//(for 3.25V)
unsigned long int ltvalue=563;//(for 2.75)
unsigned long int olvoltage=819;//(for 4V)
unsigned long int ssvalue, olvalue;

TRISBbits. TRISB2=0;//spulse
TRISBbits. TRISB6=0;//solarled
TRISBbits. TRISB3=0;//load
TRISAbits. TRISA1=1;//ol sense
TRISAbits. TRISA0=1;//solar sense
ANSEL = 0x03;
ADCON1=0x00;

	while(1)
	{
		solarled=1;//led ON to show uc working
		ssvalue=analogchannel(0);
		if(ssvalue >= ltvalue && ssvalue <= htvalue)
		{
			msdelay(5);
			if(ssvalue >= ltvalue && ssvalue <= htvalue)
			{
				spulse=1;
			}     	 
		}
		else
		spulse=0;

		if(ssvalue <= lon_value)
		{
			msdelay(5);
			if(ssvalue <= lon_value)
			{
				load=1;//light on
			}
		}	
		else
		load=0;//light off
		
		olvalue=analogchannel(1);
		if(olvalue >= olvoltage)
		{
			msdelay(5);
			if(olvalue >= olvoltage)
			{
				load=0;//light off
			}	
		}
		
	}
}

void msdelay(unsigned int time)
{
unsigned char i,j;
	for(i=0;i<time;i++)			
		for(j=0;j<165;j++);
}



[syntax]

In your second version of code, you've to set the ADCON0 for channel 1 to 0x80 and ADCON0 for channel 2 to 0x84. For ADCON1, you've to calculate using your Fosc.

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