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Jent
Joined: 04 Feb 2012
Posts: 20
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| LCD 16x2 interfacing with PIC18F4550 |
 Posted: Sat Feb 04, 2012 1:58 am |
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I'm new one here. Hope can obtain gurus help..
I intend to show character on the display on LCD 16x2. But I failed. I have read many regarding posts in this ccs forum, first time i just using lcd.c, but it seemed not to be worked. My LCD just showed all black boxes in first line, probably the initialization not going to work.
Then, i copy the code of flex.lcd.c in the ccs forum posts. I changed the pins for my board as follow:
| Code: |
#define LCD_DB1 PIN_D1
#define LCD_DB2 PIN_D2
#define LCD_DB3 PIN_D3
#define LCD_DB4 PIN_D4
#define LCD_DB5 PIN_D5
#define LCD_DB6 PIN_D6
#define LCD_DB7 PIN_D7
#define LCD_E PIN_B5
#define LCD_RS PIN_B4
#define USE_LCD_RW 1
#define LCD_RW USE_LCD_RW
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the LCD_RW have been connected to ground. Is there any problems if I define so?
The following is the coding, just follow the previous ccs forum posts:
| Code: |
#include <18F4550.h>
#fuses NOWDT, HS, NOPROTECT, NOPUT
#use delay(clock=20M, crystal)
#include <stdlib.h>
#include "flex_lcd.c"
void main()
{
lcd_init();
lcd_putc("Hello World\n");
lcd_putc("Line Number2");
delay_ms(20);
while(TRUE);
}
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Although the black boxes in the first line have been disappeared, but my LCD is still unable to show out the message, it is just blank...>.<..Hope gurus here can help me. |
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Jent
Joined: 04 Feb 2012
Posts: 20
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| Posted: Sat Feb 04, 2012 2:19 am |
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One more thing, i read the PIC18F4550 datasheet, it mentioned that PortB can be as analog pins or digital pins.
But at default they are analog pins. Since my PIC kit uses the RB4 for RS of LCD and RB5 for E of LCD...
If required to make these pins to digital, it has to disable PBADEN configuration bits.. Then how can be done in CCS C compiler? |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19555
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| Posted: Sat Feb 04, 2012 3:02 am |
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If you have LCD R/W tied to ground, you need to get _rid_ of the definitions:
#define USE_LCD_RW 1
#define LCD_RW USE_LCD_RW
The second is wrong anyway.
You #define 'USE_LCD_RW', if you are connecting the R/W pin. If not, don't define it.
Then if using a pin, LCD_RW, needs to be set to the pin number.
So with your line wired low, you must get rid of these lines.
Then in your fuses you need to add 'NOPBADEN' which says 'don't default to using the ADC on port B.
Best Wishes |
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Jent
Joined: 04 Feb 2012
Posts: 20
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| Posted: Sat Feb 04, 2012 3:34 am |
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But if didn't define for #define LCD_RW, this may cause errors in flex.lcd.c
3 errors: Undefined identifier LCD>RW
no matter how i change and edit, still the same...black boxes disappeared, but without showing any characters, just blank.. |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19555
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| Posted: Sat Feb 04, 2012 3:46 am |
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_Read_the text at the top of the flex_lcd driver.
If you get rid of the #define USE_LCD_RW, the code should not talk to the LCD R/W line at all. |
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Jent
Joined: 04 Feb 2012
Posts: 20
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| Posted: Sat Feb 04, 2012 4:03 am |
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| How to get rid? I don't too understand. Since there are some codings in flex_lcd.c are related to LCD_RW...if i didn't define it, errors appeared. |
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Jent
Joined: 04 Feb 2012
Posts: 20
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| Posted: Sat Feb 04, 2012 4:20 am |
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| Thanks so much. I just deleted the USE_LCD_RW. Finally I got the characters I want. Thank you so much...^.^ |
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[email protected]
Joined: 07 Feb 2012
Posts: 19
Location: pakistan
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| LCD Working Code |
| Posted: Mon Feb 20, 2012 7:15 am |
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| Code: |
#include<18F452.h>
#use delay(clock = 4000000)
//#use I2C(MASTER, SDA=PIN_B1, SCL=PIN_B0,FAST=400000)
//#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7)
#fuses NOWDT,NOPROTECT,NOLVP,XT
#define EN PIN_C7
#define RW PIN_C6
#define RS PIN_C5
unsigned char we[10]= "PIC LCD:";
void delay()
{
long i;
for( i=0;i<=6555;i++)
{}
}
void interface()
{
output_b(0x3c);
output_bit(EN,1);
output_bit(RS,0);
output_bit(RW,0);
delay();
output_bit(EN,0);
}
void DISPLAY_CURSOR()
{
output_b(0x08);
output_bit(EN,1);
output_bit(RS,0);
output_bit(RW,0);
delay();
output_bit(EN,1);
}
void clear_display()
{
output_b(0x01);
output_bit(EN,1);
output_bit(RS,0);
output_bit(RW,0);
delay();
output_bit(EN,0);
}
void blink()
{
output_b(0x0f);
output_bit(EN,1);
output_bit(RS,0);
output_bit(RW,0);
delay();
output_bit(EN,0);
}
void home ()
{
output_b(0x02);
output_bit(EN,1);
output_bit(RS,0);
output_bit(RW,0);
delay();
output_bit(EN,0);
}
void lcd(unsigned char ch)
{
output_b(ch);
output_bit(RS,1);
output_bit(RW,0);
output_bit(EN,1);
delay();
output_bit(EN,0);
}
void main (void)
{
int i,j,count;
for(i=0;i<3;i++)
{
interface();
delay();
}
DISPLAY_CURSOR();
delay();
clear_display();
delay();
blink();
delay();
home ();
delay();
for(j=0;j<10;j++)
{
lcd(we[j]);
//printf("char=%c",we[j]);
delay();
count=count+1;
if(count==16)
{
clear_display();
count=0;
}
}
}
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