ADC not giving proper output

[ecaits]

Dear All Friends,

I am using pin RA.0 as analog input pin (0-5V) and display on LCD in PIC16F877 using Hi-Tech C compiler.

But as per my input voltage, I am not getting output. I have interface 4-bit LCD with Port D and control bit of LCD with Port A.

I am using Right Justified output in ADRES registers.

As per 0-5V input, I should get 0-1023 in ADRES register but it is not giving. LCD is working properly.

I have attached code for reference.

 

[PA3040]

How about configuration bits
Does LCD display some thing?

 

[wp100]

Hi,

+ what PA3040 has just asked plus show your circuit diagram.

Not a C person but your use of ADCON1 and ADCON0 looks strange.

In LCD_init your ADCON1 0x06 which makes all ports Digital, assuming your adc input is RA0/AN0 ? then make it so with the other pins Digital using ADCON1 0x0E, but also add in Right Justify so it becomes 0x8E
You correctly make RA0 input with TRISA 0x01

In the ADC_init you use ADCON0 seemingly ok, but follow it with another ADCON1 which actually selects RA0, RA1 and VREF+ & VREF-.
You do not, for now need Vrefs and using those pins throws your port allocation out for the LCD control Pins, so I would remove that instruction all together.

 

[milan.rajik]

The OP has already been answered in his previous thread here. https://www.edaboard.com/threads/312181/#post1336314

He has opened another thread. He was provided links which has Hi-Tech C code for 16F877 ADC and LCD which he is using.


Edit: Explain which adc inputs you are using and measuring what? Do you want to display adc value as int or float value? See attached code and Proteus simulation.

It is MPLAB 8.92, Hi-Tech PICC 9.83 Code.

 

[ecaits]

Thank you very much. I have solve the problem.