rendered paste body/***************************************************************************/
/* */
/* LcdTest.c */
/* LCD interface implementation */
/* */
/* Version : 1.3 */
/* */
/* */
/* By: J. Winpenny */
/* */
/* Date: 19/7/1999 */
/* */
/* */
/* Mode : HD44780 type LCD displays */
/* */
/* Interface : SEL = Port A bit 3 */
/* WR = Port A bit 2 */
/* RS = Port A bit 0 */
/* Data_7 = Port B bit 7 */
/* Data_6 = Port B bit 6 */
/* Data_5 = Port B bit 5 */
/* Data_4 = Port B bit 4 */
/* */
/* Notes : Requires "Delays.c" */
/* */
/* This version is for 4 bit mode */
/* */
/* */
/***************************************************************************/
void LCD_Setup(void);
void LCD_FunctionMode(void);
void LCD_DataMode(void);
void LCD_Write_8_Bit(char);
void LCD_Write_4_Bit(char);
void LCD_Delay(void);
/* General definitions */
#define TRISA 5
#define TRISB 6
#define PORTA 5
#define PORTB 6
/***********************************************************************/
/* Definitions for the LCD interface */
/***********************************************************************/
#define LCD_SEL 3 /* Port A bit 3 ( Enables LCD ) */
#define LCD_WR 2 /* Port A bit 2 ( Logic 0 = Write ) */
#define LCD_RS 0 /* Port A bit 1 ( Register select ) */
#define LCD_DATA_4 4 /* LCD BIT 4 */
#define LCD_DATA_5 5 /* LCD BIT 5 */
#define LCD_DATA_6 6 /* LCD BIT 6 */
#define LCD_DATA_7 7 /* LCD BIT 7 */
/* */
/* */
/***********************************************************************/
/* LCD Commands ( Refer to LCD Data Sheet ) */
/* Standard command should work with most common devices */
/***********************************************************************/
/* */
#define clear_lcd 0x01 /* Clear Display */
#define return_home 0x02 /* Cursor to Home position */
#define entry_mode 0x06 /* Normal entry mode */
#define entry_mode_shift 0x07 /* - with shift */
#define system_set_8_bit 0x38 /* 8 bit data mode 2 line ( 5x7 font ) */
#define system_set_4_bit 0x28 /* 4 bit data mode 2 line ( 5x7 font ) */
#define display_on 0x0c /* Switch ON Display */
#define display_off 0x08 /* Cursor plus blink */
#define set_dd_line1 0x80 /* Line 1 position 1 */
#define set_dd_line2 0xC0 /* Line 2 position 1 */
#define set_dd_ram 0x80 /* Line 1 position 1 */
#define write_data 0x00 /* With RS = 1 */
#define cursor_on 0x0E /* Switch Cursor ON */
#define cursor_off 0x0C /* Switch Cursor OFF */
/* */
/***********************************************************************/
/* PIC PORT SETUP */
#define TxMode 0x40 /* Set option reg TMR0 interupt */
/* source from counter. */
/* Max speed prescaler ( 1:2 ) */
/* ( Not needed for LCD ) */
#define PortAConfig 0x10 /* Configure port A ( 1 = input ) */
/* RA4/RTCC = Input / RA2 = Input */
#define PortBConfig 0x0B /* Configure port B */
/* START OF MAIN */
void main(void)
{
char a;
char b;
/* First setup PIC Ports and Interrupts */
set_bit( STATUS, RP0 );
OPTION_REG = TxMode; // Set Option register.
set_tris_a( PortAConfig); // Setup ports
set_tris_b( PortBConfig );
clear_bit( STATUS, RP0 );
output_low_port_a( LCD_SEL ); // Disable LCD
disable_interrupt( GIE ); // Enable Global Interrupts
/* End of Setup */
LCD_Setup(); /* Setup the LCD device */
LCD_Write_4_Bit('L'); /* Display a test message */
LCD_Write_4_Bit('C');
LCD_Write_4_Bit('D');
LCD_Write_4_Bit(' ');
LCD_Write_4_Bit('T');
LCD_Write_4_Bit('e');
LCD_Write_4_Bit('s');
LCD_Write_4_Bit('t');
delay_s(10);
while( 1 )
{
LCD_FunctionMode();
LCD_Write_4_Bit(clear_lcd);
LCD_DataMode();
a = 'a';
for ( b = 0; b < 16; b++ ) /* Write "abcdefghijklmnop" on line 1 */
{
LCD_Write_4_Bit(a++);
delay_ms(250);
}
LCD_FunctionMode();
LCD_Write_4_Bit(set_dd_line2); /* Goto line 2 */
LCD_DataMode();
for ( b = 0; b < 10; b++ ) /* Write "qrstuvwxyz" on line 2 */
{
LCD_Write_4_Bit(a++);
delay_ms(250);
}
delay_s(5);
}
}
/***********************************/
/* Setup the lcd device */
/***********************************/
void LCD_Setup(void)
{
/* Reset the LCD */
/* WARNING, AFFECTS ALL OF PORT A */
delay_ms(30); /* Power up delay */
LCD_FunctionMode();
LCD_Write_8_Bit( system_set_4_bit ); /* This sequence resets the LCD */
delay_ms(5);
LCD_Write_8_Bit( system_set_4_bit );
delay_ms(5);
LCD_Write_8_Bit( system_set_4_bit );
delay_ms(5);
LCD_Write_4_Bit( system_set_4_bit );
delay_ms(2);
LCD_Write_4_Bit( display_off );
delay_ms(2);
LCD_Write_4_Bit( entry_mode );
delay_ms(2);
LCD_Write_4_Bit( display_on );
delay_ms(2);
LCD_Write_4_Bit( set_dd_ram );
delay_ms(2);
LCD_DataMode();
}
/* END OF MAIN */
/***********************************/
/* Put LCD in Function Mode */
/***********************************/
void LCD_FunctionMode(void)
{
output_low_port_a( LCD_RS );
LCD_Delay();
}
/***********************************/
/* Put LCD in Data Mode */
/***********************************/
void LCD_DataMode(void)
{
output_high_port_a( LCD_RS );
LCD_Delay();
}
/***********************************/
/* Write a single byte to the LCD */
/* 8 Bit Mode */
/***********************************/
void LCD_Write_8_Bit(char d )
{
output_low_port_a( LCD_WR ); /* Write Mode */
LCD_Delay();
/* Setup data */
if ( d & 0x80 )
output_high_port_b( LCD_DATA_7 );
else output_low_port_b( LCD_DATA_7 );
if ( d & 0x40 )
output_high_port_b( LCD_DATA_6 );
else output_low_port_b( LCD_DATA_6 );
if ( d & 0x20 )
output_high_port_b( LCD_DATA_5 );
else output_low_port_b( LCD_DATA_5 );
if ( d & 0x10 )
output_high_port_b( LCD_DATA_4 );
else output_low_port_b( LCD_DATA_4 );
LCD_Delay();
output_high_port_a( LCD_SEL ); /* Select LCD */
LCD_Delay();
output_low_port_a( LCD_SEL ); /* De-select LCD */
}
/***********************************/
/* Write a single byte to the LCD */
/* 4 Bit Mode */
/***********************************/
void LCD_Write_4_Bit(char d )
{
output_low_port_a( LCD_WR ); /* Write Mode */
LCD_Delay();
/* Output Higher 4 bits */
if ( d & 0x80 )
output_high_port_b( LCD_DATA_7 );
else output_low_port_b( LCD_DATA_7 );
if ( d & 0x40 )
output_high_port_b( LCD_DATA_6 );
else output_low_port_b( LCD_DATA_6 );
if ( d & 0x20 )
output_high_port_b( LCD_DATA_5 );
else output_low_port_b( LCD_DATA_5 );
if ( d & 0x10 )
output_high_port_b( LCD_DATA_4 );
else output_low_port_b( LCD_DATA_4 );
LCD_Delay();
output_high_port_a( LCD_SEL );
LCD_Delay();
output_low_port_a( LCD_SEL ); /* Clock in the data */
LCD_Delay();
d <<= 4; /* Output Lower 4 bits */
if ( d & 0x80 )
output_high_port_b( LCD_DATA_7 );
else output_low_port_b( LCD_DATA_7 );
if ( d & 0x40 )
output_high_port_b( LCD_DATA_6 );
else output_low_port_b( LCD_DATA_6 );
if ( d & 0x20 )
output_high_port_b( LCD_DATA_5 );
else output_low_port_b( LCD_DATA_5 );
if ( d & 0x10 )
output_high_port_b( LCD_DATA_4 );
else output_low_port_b( LCD_DATA_4 );
LCD_Delay();
output_high_port_a( LCD_SEL );
LCD_Delay();
output_low_port_a( LCD_SEL ); /* Clock in the data */
}
/***********************************/
/* LCD timing delay */
/* Adjust for your LCD Display */
/***********************************/
void LCD_Delay(void)
{
delay_ms(1);
}