[SOLVED] Temperature sensor using pic18f452...require urgent help!!

• Mar 18, 2012

• #1

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huzeeigat

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Hey i m making a temperature sensor using lm35 and pic18f452
the objective is to control the temperature between 25 and 27'C...when the temperature is below 25'c,a heater is to be turned on at pin RD3 and when the temperature is above 27'c,a cooling fan is to be turned on at pin RD2...I have written the code in c lang..and compiled successfully in mplab..but when i tried it on proteus along with the circuit...i get an error as follows...
Processor has been reset by watchdog timer expiring at xyz time...i disabled the wdt from mplab...and then again tried on proteus but i get the same error...i dont knw how to change the oscillator frequency in mplab...m posting the code along with the proteus ckt...can any1 tell me wat is the problem....



---------- Post added at 15:43 ---------- Previous post was at 15:31 ----------

here is an image of the simulation window that i get on proteus after i execute the above circuit

 

Last edited: Mar 18, 2012

• Mar 18, 2012

• #2

xpress_embedo

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The Problem is in Your Connection's...

The First Pin of Micro-Controller MCLR is pulled-high to Vdd by a 10K resistance and after that you have attached a capacitor to ground.
Which always reset your controller.
Remove that connection from ground.
This is causing reset

Hope this helps..

 

• Mar 18, 2012

• #3

xpress_embedo

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Do like this, as shown in the above pic

Hope this help

 

• Mar 18, 2012

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huzeeigat

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Hey thanks for ur reply....
But i am still getting the same error of processor is reset by watchdog timer...

 

• Mar 18, 2012

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xpress_embedo

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Upload your code in zip format and Proteus Simulation File...

I will see and correct your problem...

---------- Post added at 21:55 ---------- Previous post was at 21:40 ----------

Also Check PIC18F452 Configuration Bits, Set them Properly and try again i don't anyother problem.
If you could be able to upload your code and hex file and proteus file then i could do something..

 

• Mar 18, 2012

• #6

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huzeeigat

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Hey i have attached the c file and the proteus design here..have a look...

Thanks,
Regards
Huzefa Igatpuriwala

 

Attachments

• tmp sensor.zip

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• Mar 18, 2012

• #7

xpress_embedo

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I am not using the same Compiler as u are using...

Try to give me the whole project, till then i am looking at it..

I also need hex file, thats why i want whole Project in Zip Format

 

• Mar 18, 2012

• #8

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I am attaching the entire project files now...i am using mplabc18 compiler for my c code...
I checked the configuration bits and disabled the watchdog timer...i saw in one of the threads that i also have to set the oscillator frequency, but that i was unable to change in configuration bits...
And also i dont have any idea about the rest of the configuration bits..
Regards,
Huzefa

 

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• tmp sensor.zip

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• Mar 18, 2012

• #9

Tahmid

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You need to disable WDT in the configuration bits.

 

• Mar 18, 2012

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@Tahmid: I did that but still have the same error..

 

• Mar 18, 2012

• #11

xpress_embedo

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Small mistake in your code...

in the void temperature function, you have use a while loop

Have a look at it

Code:

void temperature(void)
{
ADCON0=0X81;
ADCON1=0XC5;
[B][I][U]while(1);[/U][/I][/B]
{
delay();

ADCON0bits.GO=1;
while(ADCON0bits.DONE==1);
l_byte=ADRESL;
h_byte=ADRESH;
l_byte>>=2;
l_byte &=0X3F;
h_byte<<=6;
h_byte=0XC0;
bin_temp=l_byte|h_byte;
}
}

Have you seen that while(); the semi-comma make the controller to stay here forever
Remove that

Code:

void temperature(void)
{
ADCON0=0X81;
ADCON1=0XC5;
while(1)
{
delay();

ADCON0bits.GO=1;
while(ADCON0bits.DONE==1);
l_byte=ADRESL;
h_byte=ADRESH;
l_byte>>=2;
l_byte &=0X3F;
h_byte<<=6;
h_byte=0XC0;
bin_temp=l_byte|h_byte;
}
}

---------- Post added at 22:48 ---------- Previous post was at 22:43 ----------

You can have a look at this link....

https://sites.google.com/site/coole...0/tutorial-list/temperature-monitoring-system

 

• Mar 18, 2012

• #12

Tahmid

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In the beginning of the code, after the #include statement, add these two lines:

Code:

#pragma config WDT=OFF //Turn watchdog timer off
#pragma config OSC=XT //For 4MHz oscillator

Now, I don't get any errors in simulation. Also, make the change done by arunsharma0731.

Hope this helps.
Tahmid.

 

• Mar 18, 2012

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Hey i removed the semi colon from the function but still i have the same error of processor getting reset by WDT... and i also want to ask you that in all the while loops of my code..i have a semicolon at every end...just have a look is it right?

 

• Mar 18, 2012

• #14

Tahmid

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You've probably set it from Configure > Configuration Bits. But in the past that had cause problems for me. And it's also not working now. So, just mention config bits in code by checking Configuration Bits Set in Code.

---------- Post added at 23:22 ---------- Previous post was at 23:22 ----------

huzeeigat said:

Hey i removed the semi colon from the function but still i have the same error of processor getting reset by WDT... and i also want to ask you that in all the while loops of my code..i have a semicolon at every end...just have a look is it right?

Click to expand...

Did you add the #pragma config statements?

 

• Mar 18, 2012

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xpress_embedo

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I think you don't know how to write a C Program...
You have done so many mistakes in that...
After every while() loop you have put a semicolon which means infinite loop

Tahmid have a look at code, he has used so many while loops and
statements like
while();

which is causing the controller to Hangs and reset always...

Friend first try with Simple programs then go to some advanced ones...

 

Last edited: Mar 18, 2012

• Mar 18, 2012

• #16

Tahmid

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arunsharma0731 said:

Oh My ***....

I think you don't know how to write a C Program...
You have done so many mistakes in that...
After every while() loop you have put a semicolon which means infinite loop

Click to expand...

The code is pretty messed up. The loops are all messed up.

 

• Mar 18, 2012

• #17

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@Arun and Tahmid: thanks for ur help friends...i am not getting the error of wdt now...but in proteus the circuit isnt working according to my program...when the temperature is below 25'c the led at pin rd3 should glow...and when above 27'c the led at pin rd2 should glow...can ull tell me what is the problem?
i am attaching the image and also the design file along with it...

 

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• project.zip

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• Mar 18, 2012

• #18

Tahmid

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Firstly, you should understand the while loop.

Code:

while (a == b);
{
//...........
//...........
}

In the code above, the code will check if a == b. If it does, it will stay there doing nothing until a is not equal to b. And then the part within braces is executed.

Code:

while(a==b)
{
//.......
//.......
}

In the code above, if a==b, the part within the braces is executed repeatedly until a is not equal to b.

Placing a ; after the while loop and the condition like in the 1st example I provided and like what you initially did, "terminates" the while loop execution block in the sense that it signals that it is where code execution is condition is true is limited. So, if ; is placed directly after the while loop, it's just doing nothing while the condition is true.

Hope this helps.
Tahmid.

---------- Post added at 23:35 ---------- Previous post was at 23:33 ----------

I'm looking at the corrections to be made and will let you know.

 

• Mar 18, 2012

• #19

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Yup arun..i removed all the semi colons from while loops in my code..and yes this is the first time that we are using embedded c for pic18f so i dont have much practice with i....

 

• Mar 18, 2012

• #20

xpress_embedo

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Friend have a look at this site...
I will provide you the libraries for LCD ans Serial Communication if You want..

https://sites.google.com/site/coole...0/tutorial-list/temperature-monitoring-system

And Your code is prettly ugly.. don't be sad, during starting stage all face these sort of problems..


If you want me to write a code for ur controller then give me some time i will write a one for you..
Not a big task for me...