misel0019
Joined: 04 Oct 2010
Posts: 53
Location: Dhaka
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| Intro n abt LCD |
 Posted: Wed Oct 06, 2010 9:04 am |
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Hi, all
I'm new at the world of PIC also CCS.
I'm interfacing Lcd with PIC16F876a.
I connect PC0-2 as RS,RW, E and DATA PIN as PC4-PC7.
I used crystal 8MZ and 15pf capacitor.
and thanks for Flex_LCD420
I got only one line display and its Garbage.
The program is written down
| Code: |
#include <16F876A.H>
#fuses HS, NOWDT, NOPROTECT, NOBROWNOUT, NOPUT, NOLVP
#use delay(clock = 8000000)
#include <Flex_LCD420.c>
//===================================
void main()
{
lcd_init();
printf(lcd_putc, "\f");
delay_ms(500);
while(1)
{
printf(lcd_putc, "\fThis is the 1st line");
printf(lcd_putc, "\nNext is the 2nd line");
printf(lcd_putc, "\nThis is the 3rd line");
printf(lcd_putc, "\nFinally the 4th line");
delay_ms(3000);
}
} |
Flex_LCD420 is
| Code: |
// Flex_LCD420.c
#define LCD_DC4 PIN_C4
#define LCD_DC5 PIN_C5
#define LCD_DC6 PIN_C6
#define LCD_DC7 PIN_C7
#define LCD_RS PIN_C0
#define LCD_RW PIN_C1
#define LCD_E PIN_C2
#define USE_RW_PIN 1
// These are the line addresses for most 4x20 LCDs.
#define LCD_LINE_1_ADDRESS 0x00
#define LCD_LINE_2_ADDRESS 0x40
#define LCD_LINE_3_ADDRESS 0x14
#define LCD_LINE_4_ADDRESS 0x54
#define lcd_type 2 // 0=5x7, 1=5x10, 2=2 lines(or more)
int8 lcd_line;
int8 const LCD_INIT_STRING[4] =
{
0x20 | (lcd_type << 2), // Set mode: 4-bit, 2+ lines, 5x8 dots
0xc, // Display on
1, // Clear display
6 // Increment cursor
};
//-------------------------------------
void lcd_send_nibble(int8 nibble)
{
// Note: !! converts an integer expression
// to a boolean (1 or 0).
output_bit(LCD_DC4, !!(nibble & 1));
output_bit(LCD_DC5, !!(nibble & 2));
output_bit(LCD_DC6, !!(nibble & 4));
output_bit(LCD_DC7, !!(nibble & 8));
delay_cycles(1);
output_high(LCD_E);
delay_us(2);
output_low(LCD_E);
}
//-----------------------------------
// This sub-routine is only called by lcd_read_byte().
// It's not a stand-alone routine. For example, the
// R/W signal is set high by lcd_read_byte() before
// this routine is called.
#ifdef USE_RW_PIN
int8 lcd_read_nibble(void)
{
int8 retval;
// Create bit variables so that we can easily set
// individual bits in the retval variable.
#bit retval_0 = retval.0
#bit retval_1 = retval.1
#bit retval_2 = retval.2
#bit retval_3 = retval.3
retval = 0;
output_high(LCD_E);
delay_us(1);
retval_0 = input(LCD_DC4);
retval_1 = input(LCD_DC5);
retval_2 = input(LCD_DC6);
retval_3 = input(LCD_DC7);
output_low(LCD_E);
delay_us(1);
return(retval);
}
#endif
//---------------------------------------
// Read a byte from the LCD and return it.
#ifdef USE_RW_PIN
int8 lcd_read_byte(void)
{
int8 low;
int8 high;
output_high(LCD_RW);
delay_cycles(1);
high = lcd_read_nibble();
low = lcd_read_nibble();
return( (high<<4) | low);
}
#endif
//----------------------------------------
// Send a byte to the LCD.
void lcd_send_byte(int8 address, int8 n)
{
output_low(LCD_RS);
#ifdef USE_RW_PIN
while(bit_test(lcd_read_byte(),7)) ;
#else
delay_us(60);
#endif
if(address)
output_high(LCD_RS);
else
output_low(LCD_RS);
delay_cycles(1);
#ifdef USE_RW_PIN
output_low(LCD_RW);
delay_cycles(1);
#endif
output_low(LCD_E);
lcd_send_nibble(n >> 4);
lcd_send_nibble(n & 0xf);
}
//----------------------------
void lcd_init(void)
{
int8 i;
lcd_line = 1;
output_low(LCD_RS);
#ifdef USE_RW_PIN
output_low(LCD_RW);
#endif
output_low(LCD_E);
// Some LCDs require 15 ms minimum delay after
// power-up. Others require 30 ms. I'm going
// to set it to 35 ms, so it should work with
// all of them.
delay_ms(35);
for(i=0 ;i < 3; i++)
{
lcd_send_nibble(0x03);
delay_ms(5);
}
lcd_send_nibble(0x02);
for(i=0; i < sizeof(LCD_INIT_STRING); i++)
{
lcd_send_byte(0, LCD_INIT_STRING[i]);
// If the R/W signal is not used, then
// the busy bit can't be polled. One of
// the init commands takes longer than
// the hard-coded delay of 50 us, so in
// that case, lets just do a 5 ms delay
// after all four of them.
#ifndef USE_RW_PIN
delay_ms(5);
#endif
}
}
//----------------------------
void lcd_gotoxy(int8 x, int8 y)
{
int8 address;
switch(y)
{
case 1:
address = LCD_LINE_1_ADDRESS;
break;
case 2:
address = LCD_LINE_2_ADDRESS;
break;
case 3:
address = LCD_LINE_3_ADDRESS;
break;
case 4:
address = LCD_LINE_4_ADDRESS;
break;
default:
address = LCD_LINE_1_ADDRESS;
break;
}
address += x-1;
lcd_send_byte(0, 0x80 | address);
}
//-----------------------------
void lcd_putc(char c)
{
switch(c)
{
case '\f':
lcd_send_byte(0,1);
lcd_line = 1;
delay_ms(2);
break;
case '\n':
lcd_gotoxy(1, ++lcd_line);
break;
case '\b':
lcd_send_byte(0,0x10);
break;
default:
lcd_send_byte(1,c);
break;
}
}
//------------------------------
#ifdef USE_RW_PIN
char lcd_getc(int8 x, int8 y)
{
char value;
lcd_gotoxy(x,y);
// Wait until busy flag is low.
while(bit_test(lcd_read_byte(),7));
output_high(LCD_RS);
value = lcd_read_byte();
output_low(LCD_RS);
return(value);
}
#endif |
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