Help for my project(16f877,2x16LCD,)

[karamastik]

Hello ! As you see i'm a newbee .
(Merhaba arkadaşlar.)
I've started to learn about a pic for about a month ago .
I learned to write something to the LCD with 2 lines(rows).
This was a first step for me to learn the 'p' of pic.
I'm an undergraduate student and my final project is to show the voltage change from the output of LM358 IC with 16f877 with using 2x16 LCD.
I'll show the change as the bar graph.
I have square wave 15V from the LM358 IC output.
The output mostly stays about 15V , so the ADC will be vice-versa.
I learned that 16f877 has 10 channels ADC , so we have 0-1023 interval.
As i said above , the peak of the signal is 15V and as i said above it's a square wave.
The most important point is , the ADC must be vice-versa.
For example : for my 15-14V input , the first interval must be 0-68 , for 13-12V input , second interval : 68-136 ...
I'm using pic basic pro and I don't know how to write a program .
And i read about LCD bar graphs , but i couldn't make it. ( http://www.picbasic.co.uk/forum/showthread.php?t=2359 )
Here is what i learned about pic :

@ DEVICE pic16F877
@ DEVICE pic16F877, WDT_on
@ DEVICE pic16F877, PWRT_ON
@ DEVICE pic16F877, PROTECT_OFF
@ DEVICE pic16F877, HS_OSC


DEFINE LCD_DREG PORTB
DEFINE LCD_DBIT 0
DEFINE LCD_RSREG PORTE
DEFINE LCD_RSBIT 1
DEFINE LCD_EREG PORTE
DEFINE LCD_EBIT 0
DEFINE LCD_RWREG PORTE
DEFINE LCD_RWBIT 2
DEFINE LCD_BITS 8
DEFINE LCD_LINES 2

DEFINE LCD_COMMANDUS 1000
DEFINE LCD_DATAUS 225

DEFINE ADC_BITS 10
DEFINE ADC_CLOCK 2
DEFINE ADC_SAMPLEUS 100
ADCON1=%10001110


TRISB=0
TRISE=0


LOW PORTE.2


LCDOUT $FE,1
PAUSE 200

LCDOUT $FE,2,"PIC BASIC"
LCDOUT $FE,$C0,"PRO"

END

I really need help .
Thank you

[mackrackit]

First you will need a 3 to 1 voltage divider so that 15 volts looks like 5.

Then this should get you started with ADC.
http://www.rentron.com/PICX2.htm

[karamastik]

Hmm , thank you .
Let's think , if i want to make it with 5V not 15V .
I just want to learn the main idea.
I think , if i learn the main idea , maybe i can go on with 15V.
In fact , i can change the output voltage from 1.67 V to 15V .
In this project we wanted to have good resolution , and we decided to get 15V from output.
As i said , let's think , the input changes 0-5V.
Thank you
By the way , my main project was to build an cell phone detector and i did it with a small circuit. In this circuit there are 2 same RF subcircuits ; one for the left side detection and the other side is for the right side detection.
We amplified the signals with LM358 and we may get output from 1.67 to 15V . ( with gain changing)
Finally we want to show the voltage change with the LCD bar graphs.
The first line of the LCD will be left channel and the second line will be the right channel .

[mackrackit]

Do small steps.
You have the LCD working.
Now make the ADC work with 8 bit resolution.
Then do two ADC channels.
Then work on 10 bit for more accuracy.
Then work on the bar graph.

[karamastik]

Okay ,
for ADC :

PORTA = %00000001
RAW var word ' the input voltage
volt var word
Mvolt var byte

START:

ADCIN 0,RAW ' Analog read from #ch0 and move it to RAW
LOOK : IF ADCON0.2=1 THEN LOOK ' when ADC finished ADCON0.2=0
' for 0-5V , 0-1024 - > 5/1024 = 0.0048828 = very small number
'0.0048828*1000 = 4.8828 ( raw/V)
'4.8828 * 256 = 1250 ( 1250 = 5/1024 * 256*1000 ) we made 32bits calculation
Volt=(Raw*/1250)/100
MVolt=Volt//10 ' Mvolt = Volt mod 10
Volt=Volt/10
LCDOUT $FE,2,"VOLT=",#VOLT,",",#Mvolt
PAUSE 500
GOTO START

I tried to read the voltage from LM358 and to write the LCD as Volt.Mvolt
I'm waiting for help.
Thanks.

[karamastik]

Sorry for the flood , but i must ;
i changed the ADC codes , but volt variable does not accept floating numbers :

START:

ADCIN 0,RAW
LOOK : IF ADCON0.2=1 THEN LOOK
Volt=(0,0048828125*RAW)*1000
MVolt=Volt//10 ' Mvolt = Volt mod 10
LCDOUT $FE,2,"VOLT=",#VOLT,",",#Mvolt
PAUSE 500
GOTO START