Help using LM35 with 16F877A

[Asaeed]

I'm using this code to interface LM35 with 16F877A
sbit LCD_RS at RD0_bit;
sbit LCD_EN at RD1_bit;
sbit LCD_D4 at RD4_bit;
sbit LCD_D5 at RD5_bit;
sbit LCD_D6 at RD6_bit;
sbit LCD_D7 at RD7_bit;
sbit LCD_RS_Direction at TRISD0_bit;
sbit LCD_EN_Direction at TRISD1_bit;
sbit LCD_D4_Direction at TRISD4_bit;
sbit LCD_D5_Direction at TRISD5_bit;
sbit LCD_D6_Direction at TRISD6_bit;
sbit LCD_D7_Direction at TRISD7_bit;
char *tempC = "000.0";
unsigned int tempinC;
unsigned long temp_value;
void Display_Temperature( ) {
if (tempinC/10000)
tempC[0] = tempinC/10000 + 48;
else tempC[0] = ' ';
tempC[1] = (tempinC/1000)%10 + 48;
tempC[2] = (tempinC/100)%10 + 48;
tempC[4] = (tempinC/10)%10 + 48;
Lcd_Out(2, 6, tempC);
}
void main() {
ADCON1 = 0b00000001;
TRISD = 0b00000000;
TRISA = 0b11111111;
Lcd_Init();
Lcd_Cmd(_LCD_CLEAR);
Lcd_Cmd(_LCD_CURSOR_OFF);
Lcd_Out(2,1,"temp=");
Lcd_Chr(2,11,223);
Lcd_out(2,12," C");

while(1) {
temp_value = ADC_Read(0);
temp_value = temp_value*488;
tempinC = temp_value/10;
Display_Temperature();
Delay_ms(1000); // Temperature sampling at 1 sec interval
}
}

it works great on the proteus simulator but it didn't work in the real life the Lcd didn't show anything just turned its light on ..

Please any Help .

 

[Ian Rogers]

One of the favourites is the XT vs HS osc settings.... If the OSC is 4mhz < set XT otherwise 4mhz > its HS...... They wont boot if this setting is wrong.

ISIS doesn't use these settings, so it runs in simulation

 

[Asaeed]

thnx for replying ,, But i'm using Xt Mode already ..

 

[Ian Rogers]

If that be the case.. Check all your connections.... What did you do with MCLR?

 

[3v0]

Asaeed please try to use post titles that indicate what your post is about.

"Help using LM35 with 16F877A " would have been an good title.

I hope you get it worked out.

 

[ericgibbs]

hi H,
Helpful suggestion.

E

 

[Mr RB]

...
...it works great on the proteus simulator but it didn't work in the real life the Lcd didn't show anything just turned its light on ..
Please any Help .

OK, if the LCD does not display you can strip the code down to just initialise the LCD and write a word to the screen.

You seem to be using standard compiler LCD functions, which should work ok. Mains things to check will be;
1. wiring! all the LCD wires need to be correct!
2. power to LCD.
3. CONTRAST pot! This is a common one. It needs to be connected correct and adjusted before text will display.
4. maybe plug in a different LCD, that will tell if the first one is faulty.

 

[Asaeed]

Asaeed please try to use post titles that indicate what your post is about.

"Help using LM35 with 16F877A " would have been an good title.

I hope you get it worked out.

Ok Np .. it's my first

 

[Asaeed]

If that be the case.. Check all your connections.... What did you do with MCLR?

It's Connected To vcc Through 1K Res .. and a switch to Gnd to activate it ..

 

[Asaeed]

OK, if the LCD does not display you can strip the code down to just initialise the LCD and write a word to the screen.

You seem to be using standard compiler LCD functions, which should work ok. Mains things to check will be;
1. wiring! all the LCD wires need to be correct!
2. power to LCD.
3. CONTRAST pot! This is a common one. It needs to be connected correct and adjusted before text will display.
4. maybe plug in a different LCD, that will tell if the first one is faulty.

Thnx For ur suggestions But ,

i'm Already Do A S.C test .. and used a short code just t display my Name "Lcd_out(1, 1, "Ahmed")!!
the Lcd Is Powered correctly I think As It Lights ON All The Digits..
I thought The prob with the Pot First So I Disconnect it .. "Vss=Gnd ,Vdd=Vcc , Vee=Vcc ,Bl-=Gnd ,Hl+=Vcc,RW=Gnd, Rs,E,D4: D7 To the Pic "

 

[Ian Rogers]

What happens if you change the 1k for a 10k..... With a 1k it will sometimes not boot.

 

[Mr RB]

...
i'm Already Do A S.C test .. and used a short code just t display my Name "Lcd_out(1, 1, "Ahmed")!!

Did that test work?

...
I thought The prob with the Pot First So I Disconnect it .. "Vss=Gnd ,Vdd=Vcc , Vee=Vcc ...
...

OK, if you don't have the pot connected you need to make Vee = 0v (Gnd).

And it is still best to connect the pot, as best display is often when Vee = 0.5v or so.

 

[Asaeed]

Did that test work?

No :\


OK, if you don't have the pot connected you need to make Vee = 0v (Gnd).

And it is still best to connect the pot, as best display is often when Vee = 0.5v or so.

When i connected it to Gnd the Lcd Turned off !!! And nothing appear at all :|

 

[Mr RB]

Most LCDs will work fine with Vee = 0v. Some look a bit better with a small voltage on Vee, like 0.5v I mentioned.

I think you should connect the pot up again, chech your wiring, and start posting some photos of your display.