temperature sensor -PIC 16f877

[jayanth.devarayanadurga]

You have to da as mentioned bu themask and configure ADCON1 register to use Vref. What Compiler are you using? Go to mikroE website and there is a free online book PIC Microcontrollers. Read it.

 

[paulfjujo]

hello,

You need to use an external VREF.
This means you connect a +1V circuit to the RA3/AN3/VREF pin of the PIC16F877a and enable this pin in your code as VREF+ instead of digital I/O or analog input.

you can not use a so low value as 1V for +vref
microchip recommand more than 2v between -vref and + vref
for 1v as full scale you must use an aop amplifier
or an external adc 12 or 16 bits. to increase resolution.

 

[themask]

Yes paul, that is correct...

To be honest I dont know why it is 2V, but it is what it is.

But then again its just an LM35 sensor, no need to complicate the hardware if you can get away with it :lol:

I havent encountered any problem using less than 2V, and havent read about anybody having the same. I used 2-2.5V at the start, but it is quite high for me so i tried 1.5V most of the time

To bad, though, that the PIC16F877a doesnt have an internal VREF, like the 1.1 for ATmega or 2V for ez8 chips

 

[d_ota]

help...
please send me the code in microbasic and the design simulation in proteus

 

[den23401]

Good day tahmid thank you for all your contribution in this forum, please I want to have wide knowledge on pic so I want to know the kind of books I will buy, sites I am to visits, examples of projects that I can lay my heads on and everything about programming thank you for your fast responses.