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Chaud
Joined: 11 Jan 2012
Posts: 39
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| Hello im newbie,need a bit help to simple write in my LCD |
 Posted: Wed Jan 11, 2012 8:33 am |
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Hello, i have PIC18F2550 and i want to write in my LCD , the string "hello world", i found some tutorials and i code this:
| Code: | #include <18f2550.h>
#use delay(clock=20M)
#include <lcd.c>
#define LCD_ENABLE_PIN PIN_RB0
#define LCD_RS_PIN PIN_RB1
#define LCD_RW_PIN PIN_RB2
#define LCD_DATA4 PIN_RB3
#define LCD_DATA5 PIN_RB4
#define LCD_DATA6 PIN_RB5
#define LCD_DATA7 PIN_RB6
void main()
{
lcd_init();
lcd_gotoxy(1,1);
lcd_putc("Hello world");
}
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But on my LCD I only see this:
[][][][][][][][][][][][] ( full black rectangles in all LCD chars)
It sounds like LCD is doing init, but isn't sending the string.
Can you help me there??
Thanks,
Chaud |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19552
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| Posted: Wed Jan 11, 2012 8:59 am |
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The LCD PIN definitions need to be _before_ of LCD.C. Otherwise it'll use it's default pins......
The block display is what you get 'by default' from the LCD, with no communication at all.
Best Wishes |
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Chaud
Joined: 11 Jan 2012
Posts: 39
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| Posted: Wed Jan 11, 2012 9:04 am |
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| Ttelmah wrote: | The LCD PIN definitions need to be _before_ of LCD.C. Otherwise it'll use it's default pins......
The block display is what you get 'by default' from the LCD, with no communication at all.
Best Wishes |
Hmm I see, I did it but know I get 40+ errors, all things like this:
"Undefined identifier PIN_RB6" etc etc for all pins
Aren't they identified already?? |
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sahu77
Joined: 08 Sep 2011
Posts: 202
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| Re: Hello im newbie,need a bit help to simple write in my LC |
| Posted: Wed Jan 11, 2012 9:15 am |
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| Chaud wrote: | Hello, i have PIC18F2550 and i want to write in my LCD , the string "hello world", i found some tutorials and i code this:
| Code: | #include <18f2550.h>
#use delay(clock=20M)
#include <lcd.c>
#define LCD_ENABLE_PIN PIN_RB0
#define LCD_RS_PIN PIN_RB1
#define LCD_RW_PIN PIN_RB2
#define LCD_DATA4 PIN_RB3
#define LCD_DATA5 PIN_RB4
#define LCD_DATA6 PIN_RB5
#define LCD_DATA7 PIN_RB6
void main()
{
lcd_init();
lcd_gotoxy(1,1);
lcd_putc("Hello world");
}
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But on my LCD I only see this:
[][][][][][][][][][][][] ( full black rectangles in all LCD chars)
It sounds like LCD is doing init, but isn't sending the string.
Can you help me there??
Thanks,
Chaud |
use this | Code: |
#define enable PIN_RB0
#define rs PIN_RB1
#define rw PIN_RB2
#define D4 PIN_RB3
#define D5 PIN_RB4
#define D6 PIN_RB5
#define D7 PIN_RB6 |
hope help u
_________________
sahu |
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Chaud
Joined: 11 Jan 2012
Posts: 39
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| Re: Hello im newbie,need a bit help to simple write in my LC |
| Posted: Wed Jan 11, 2012 9:17 am |
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| sahu77 wrote: |
use this | Code: |
#define enable PIN_RB0
#define rs PIN_RB1
#define rw PIN_RB2
#define D4 PIN_RB3
#define D5 PIN_RB4
#define D6 PIN_RB5
#define D7 PIN_RB6 |
hope help u |
got same errors,they are located in "lcd.c" |
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Chaud
Joined: 11 Jan 2012
Posts: 39
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| Posted: Wed Jan 11, 2012 9:38 am |
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| Porblem was i need to write PIN_Bx isntead of PIN_RBx, thanks for help , problem solved |
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Chaud
Joined: 11 Jan 2012
Posts: 39
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| Posted: Wed Jan 11, 2012 9:51 am |
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any1 know how to print "int values" with lcd_putc??
im doing this:
lcd_putc("Volts: %f", value);
And i get "Expecting a close paren" error |
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sahu77
Joined: 08 Sep 2011
Posts: 202
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| Posted: Wed Jan 11, 2012 10:13 am |
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| Chaud wrote: | any1 know how to print "int values" with lcd_putc??
im doing this:
lcd_putc("Volts: %f", value);
And i get "Expecting a close paren" error |
use this | Code: | lcd_gotoxy(1,1);
printf ( lcd_putc,"Volts ""%lu ",value); |
_________________
sahu |
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Chaud
Joined: 11 Jan 2012
Posts: 39
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| Posted: Wed Jan 11, 2012 10:38 am |
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Yeah it works, im doing a digital A/D converter, with ADC=8 bits
8 bits = 255 decimal
so
1= 0,019 V
255 = 5V
and i use this
value = read_Adc();
volts = 0.019 * value;
but to write on LCD, he only write decimal number
example, conversion = 4,995 volts
LCD screen = 4
with your code-> printf ( lcd_putc,"Volts ""%lu ",volts);
How can i print all numbers? and do you where i can see all sintaxes? like %lu
Thanks for help |
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sahu77
Joined: 08 Sep 2011
Posts: 202
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| Posted: Wed Jan 11, 2012 10:56 am |
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| Chaud wrote: | Yeah it works, im doing a digital A/D converter, with ADC=8 bits
8 bits = 255 decimal
so
1= 0,019 V
255 = 5V
and i use this
value = read_Adc();
volts = 0.019 * value;
but to write on LCD, he only write decimal number
example, conversion = 4,995 volts
LCD screen = 4
with your code-> printf ( lcd_putc,"Volts ""%lu ",volts);
How can i print all numbers? and do you where i can see all sintaxes? like %lu
Thanks for help |
what u want display ,
example, conversion = 4.995 volts or
conversion = 49.95 volts or
conversion = 499.5 volts or
conversion = 4995 volts
_________________
sahu |
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Chaud
Joined: 11 Jan 2012
Posts: 39
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| Posted: Wed Jan 11, 2012 11:03 am |
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I want to display "4,995 volts" can you explain how I do it??
And one more simple question, is there a command to clean all info from lcd??
| Code: |
while(1)
{
value = read_Adc();
lcd_gotoxy(1,1);
printf ( lcd_putc,"");
lcd_gotoxy(1,1);
printf ( lcd_putc,"%lu ""Volts",value);
}
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I'm using lcd_putc(""), but for example if it goes from 100 to 99, it appears "100 volts" to "99 voltss" with double "s".
Thanks for all help |
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sahu77
Joined: 08 Sep 2011
Posts: 202
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| Posted: Wed Jan 11, 2012 11:15 am |
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OK now change in your code as ....
| Code: |
/*******************************************************
ADC Defines
*******************************************************/
#bit ADFM = 0x1F.7 // A/D Result Formed Select bit
// 0=Left Justified, 1=Right Justified
#define ADC_AVERAGE_COUNT 10 // # of times to average ADC_Value
#define ADC_DELAY 1 // Change to "1" for 1 ms
#define ADC_2TAD 1 // Wait 1 ms for 2TAD to complete before doing another AD conversion.
int16 getchreading(int channel)
{
int32 tlong;
int1 done; // Put local variable at beginning of code block
int x; // Number of times to average ADC value
int16 temp_result, adc_value;
set_adc_channel(channel); // Select Channel
// Average ADC value
temp_result = 0;
for (x=1; x<=ADC_AVERAGE_COUNT; x++)
{
delay_us(ADC_DELAY); //Charge capacitor
read_adc(ADC_START_ONLY); //Do A/D conversion
done == adc_done();
while(!done) {
done = adc_done();
}
temp_result += read_adc(); // Read A/D register . Pin A0 in an input
delay_ms(ADC_2TAD); // Wait 2 TADs before doing another A/D conversion
}
adc_value = temp_result / ADC_AVERAGE_COUNT;
tlong = (int32)ADC_value*6000/255; //1023;
return (int32) tlong;
}
void Process_display(void)
{
int16 volt ;
ch_0 = getchreading(0); // ch_0 mens AN0
involts =(int16) ch_0 / 1000
lcd_gotoxy(1,1);
printf ( lcd_putc,"Volts ""%lu ",volt);
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hope help, now solve your problem ? or anything rest ?
_________________
sahu |
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RF_Developer
Joined: 07 Feb 2011
Posts: 839
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| Posted: Wed Jan 11, 2012 11:26 am |
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| Chaud wrote: |
with ADC=8 bits
8 bits = 255 decimal
so
1= 0,019 V
255 = 5V
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No, not quite right. 256 is 5V, not 255. So 1 bit is 0.0194549560546875V. That's way too precise for float maths however, so call it 19.45mV per bit. In general for unipolar ADCs the resolution is Vref/2^Bits and the range in volts is 0 to (2^Bits - 1) * resolution. Vin = Vref is overrange, not just Vin > Vref. Put another way the range is zero to one bit's worth less than the reference voltage.
I normally do all this in #defines so that I don't calculate the conversions, the compiler does it for me. If I change from 10 to 12 bit ADCs all I do is change one constant, from 1024 to 4096, everything else tracks that change automatically. I include analogue gains and that sort of thing. Here's one from one of my projects:
| Code: |
#define ADC_COUNTS 1024 // 10 bits unipolar
// The volts per dB is fixed and well defined. Its
// derived from the -22mv per dB of the log detector multiplied by
// the analogue gain, i.e. -3.
#define VOLTS_PER_DB -.022f // -22mV/dB
#define GAIN -3.0f // * -3 analogue gain
#define DB_PER_BIT ((ADC_VREF / ADC_COUNTS) / (VOLTS_PER_DB * GAIN) )
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This is a very common mistake, and I see quite experienced embedded engineers making it too. It makes a very small, insignificant error at 8 bits. A small error at ten bits that might cause trouble, and if you are going for 12 bits and more you should get it right! Why not get it right now and you're much more likely to keep on getting it right.
RF Developer |
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