hi, guys I have a doubt regarding interfacing lcd to arm7. I have an lpc2148 development board. This board did have a lcd interfacing example. I also have another program I got from internet. I see that the function to initialize the lcd are written in different ways in both the examples. In the example I got with the board the "void lcd_init()" is little complex. But the other example I got from internet the has "void init_lcd( void )" written in a simple way. I have edited and tried the codes in different ways and I see only the code I received with the board works. I am new to ARM, but I don't think this should be correct, we should be able to make new codes. Hoping someone can understand my doubt.
CODE THAT CAME WITH THE DEVELOPMENT BOARD
#include <LPC214x.H> #define LCD_RS (1<<10) #define LCD_RW (1<<12) #define LCD_EN (1<<13) #define LCD_D4 (1<<20) #define LCD_D5 (1<<21) #define LCD_D6 (1<<22) #define LCD_D7 (1<<23) #define LCD_DATA_MASK (LCD_D7|LCD_D6|LCD_D5|LCD_D4) #define LCD_IOALL_MASK (LCD_D7|LCD_D6|LCD_D5|LCD_D4|LCD_RS|LCD_EN|LCD_RW) //*************************** void enable_lcd(void) { unsigned int i; IOSET0 = LCD_EN; for (i=0;i<400000;i++); IOCLR0 = LCD_EN; } //************************** void lcd_init() { unsigned int i; PINSEL1 = 0x00000000; IODIR0 |= LCD_IOALL_MASK; for (i=0;i<1000;i++); IOCLR0 = (LCD_IOALL_MASK); IOSET0 = (LCD_D5|LCD_D4); enable_lcd(); for (i=0;i<100;i++); IOCLR0 = (LCD_IOALL_MASK); IOSET0 = (LCD_D5|LCD_D4); enable_lcd(); for (i=0;i<100;i++); IOCLR0 = (LCD_IOALL_MASK); IOSET0 = (LCD_D5|LCD_D4); enable_lcd(); delay(10000); while(busy_lcd()); IOCLR0 = (LCD_IOALL_MASK); IOSET0 = (LCD_D5); enable_lcd(); delay(10000); while(busy_lcd()); lcd_write_control(0x28); lcd_write_control(0x0C); lcd_write_control(0x06); lcd_write_control(0x01); lcd_write_control(0x0F); lcd_write_control(0x01); for (i=0;i<100000;i++); } //***************************** char busy_lcd(void) { unsigned long busy_status; unsigned int i; IODIR0 &= LCD_DATA_MASK; IOCLR0 = LCD_RS; IOSET0 = LCD_RW; IOSET0 = LCD_EN; for (i=0;i<1000;i++); busy_status = (IOPIN1 & 0x80000000); if(busy_status == 0x80000000) { IOCLR0 = LCD_EN; IOCLR0 = LCD_RW; IODIR0 |= LCD_IOALL_MASK; return 1; } else { IOCLR0 = LCD_EN; IOCLR0 = LCD_RW; IODIR0 |= LCD_IOALL_MASK; return 0; } } //****************************** void lcd_out_data4(unsigned char val) { IOCLR0 = (LCD_DATA_MASK); IOSET0 = (val<<20); } //********************************** void lcd_write_byte(unsigned char val) { lcd_out_data4((val>>4)&0x0F); enable_lcd(); lcd_out_data4(val&0x0F); enable_lcd(); delay(100000); // while(busy_lcd()); } //********************************** void lcd_write_control(unsigned char val) { IOCLR0 = LCD_RS; lcd_write_byte(val); } //********************************** void lcd_write_ascii(unsigned char c) { IOSET0 = LCD_RS; lcd_write_byte(c); } //******************************** void goto_cursor(unsigned char i) { i |= 0x80; lcd_write_control(i); } //******************************* void lcd_print(unsigned char* str) { int i; for (i=0;i<16 && str[i]!=0;i++) { lcd_write_ascii(str[i]); } } //****************************** void delay(unsigned long int count1) { while(count1 > 0) {count1--;} }
I will copy the other code in the below thread
Sorry the second code didn't come properly. Let me post it again THE OTHER EXAMPLE here i see the initialization of the lcd is done in a very simple way
#include <LPC214x.H> #include "lcd.h" #define LCD_DATA_DIR IO0DIR #define LCD_DATA_SET IO0SET #define LCD_DATA_CLR IO0CLR #define LCD_CTRL_DIR IO0DIR #define LCD_CTRL_SET IO0SET #define LCD_CTRL_CLR IO0CLR #define LCDRS (1 << 10) #define LCDRW (1 << 12) #define LCDEN (1 << 13) #define LCD_D4 (1 << 20) #define LCD_D5 (1 << 21) #define LCD_D6 (1 << 22) #define LCD_D7 (1 << 23) #define LCD_DATA_MASK (LCD_D4 | LCD_D5 | LCD_D6 | LCD_D7) #define LCD_BUSY_FLAG LCD_D7 //****************************************************** void delay(int count) { int j=0,i=0; for(j=0;j<count;j++) { for(i=0;i<35;i++); } } //****************************** void wait_lcd( void ) { LCD_CTRL_CLR |= LCDRS; LCD_CTRL_SET |= LCDRW |LCDEN; while(IO0PIN & LCD_BUSY_FLAG); LCD_CTRL_CLR |= LCDEN | LCDRW; LCD_DATA_DIR |= LCD_DATA_MASK; delay(100); } //****************************** void lcd_command_write( unsigned char command ) { unsigned char temp=0; unsigned int temp1=0; temp=command; temp=(temp>>4)&0x0F; temp1=(temp<<20)&LCD_DATA_MASK; LCD_CTRL_CLR = LCDRS; LCD_CTRL_SET = LCDEN; LCD_DATA_CLR = LCD_DATA_MASK; LCD_DATA_SET = temp1; delay(10000); LCD_CTRL_CLR = LCDEN; temp=command; temp&=0x0F; temp1=(temp<<20)&LCD_DATA_MASK; delay(100*2); LCD_CTRL_CLR |= LCDRS; LCD_CTRL_SET |= LCDEN; LCD_DATA_CLR = LCD_DATA_MASK; LCD_DATA_SET = temp1; delay(10000); LCD_CTRL_CLR |= LCDEN; wait_lcd(); } //****************************** void set_lcd_port_output( void ) { LCD_CTRL_DIR |= ( LCDEN | LCDRS | LCDRW ); LCD_CTRL_CLR |= ( LCDEN | LCDRS | LCDRW ); LCD_DATA_DIR |= LCD_DATA_MASK; } //******************************* void lcd_clear( void) { lcd_command_write( 0x01 ); } //******************************** int lcd_gotoxy( unsigned int x, unsigned int y) { int retval = 0; if( (x > 1) && (y > 15) ) { retval = -1; } else { if( x == 0 ) { lcd_command_write( 0x80 + y ); } else if( x==1 ){ lcd_command_write( 0xC0 + y ); } } return retval; } //****************************** void lcd_data_write( unsigned char data ) { unsigned char temp=0; unsigned int temp1=0; temp=data; temp=(temp>>4)&0x0F; temp1=(temp<<20)&LCD_DATA_MASK; LCD_CTRL_SET |= LCDEN|LCDRS; LCD_DATA_CLR = LCD_DATA_MASK; LCD_DATA_SET = temp1; LCD_CTRL_CLR |= LCDEN; temp=data; temp&=0x0F; temp1=(temp<<20)&LCD_DATA_MASK; LCD_CTRL_SET |= LCDEN|LCDRS; LCD_DATA_CLR = LCD_DATA_MASK; LCD_DATA_SET = temp1; LCD_CTRL_CLR |= LCDEN; wait_lcd(); } //******************************* void lcd_putchar( int c ) { lcd_data_write( c ); } //******************************* void lcd_putstring( unsigned char line, char *string ) { unsigned char len = MAX_CHAR_IN_ONE_LINE; lcd_gotoxy( line, 0 ); while(*string != '\0' && len--) { lcd_putchar( *string ); string++; } } //******************************* void lcd_backlight_on() { LCD_BACK_LIGHT_DIR |= LCD_BACKLIGHT; LCD_BACK_LIGHT_SET |= LCD_BACKLIGHT; } //********************************* void turn_off_lcd_back_light_cb(void) { LCD_BACK_LIGHT_DIR |= LCD_BACKLIGHT; LCD_BACK_LIGHT_CLR |= LCD_BACKLIGHT; } //********************************* void init_lcd( void ) { set_lcd_port_output(); delay(100*100); lcd_command_write(0x28); lcd_clear() ; lcd_command_write(0x02); lcd_command_write(0x06); lcd_command_write(0x0C); lcd_gotoxy(0, 0); lcd_clear(); }
I have copied only the lcd file, please let me know, if I need to explain anything
Check the LCD Initialization section in www.ocfreaks.com/.../
Thanks, I will go through the link
Thanks Foster, the link did help me.