lcd.c


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#include <lpc21xx.h>

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#define LCD_RS  1 << 16

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#define LCD_R_W  1 << 17

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#define LCD_E  1 << 18

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#define LCD_D4  1 << 19

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#define LCD_D5  1 << 20

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#define LCD_D6  1 << 21

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#define LCD_D7  1 << 22

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void enable(void);

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void delay_30ms(void);

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void delay_1_53ms(void);

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void delay_39us(void);

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void main(void) 

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{    

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  IODIR1 |= LCD_RS | LCD_R_W | LCD_E | LCD_D4 | LCD_D5 | LCD_D6 | LCD_D7;  //portbits als output definieren

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  IOCLR1 |= LCD_RS | LCD_R_W | LCD_E | LCD_D4 | LCD_D5 | LCD_D6 | LCD_D7; //portbits auf low

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  delay_30ms();  // wait for power on of the lcd

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  //funtion set ->  4-bit mode, 2 rows, 5x7 dots

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  IOSET1 |= LCD_D5;

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  IOCLR1 |= LCD_RS | LCD_R_W | LCD_D4 | LCD_D6 | LCD_D7;

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  enable();

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  delay_30ms();

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  enable();

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  delay_30ms();

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  IOSET1 |= LCD_D7; 

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  IOCLR1 |= LCD_RS | LCD_R_W | LCD_D6; 

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  enable();

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  delay_30ms();

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  //display on, cursor on, blink on

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  IOCLR1 |= LCD_RS | LCD_R_W | LCD_D4 | LCD_D5 | LCD_D6 | LCD_D7; 

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  enable();

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  delay_30ms();

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  IOSET1 |= LCD_D4 | LCD_D5 | LCD_D6 | LCD_D7; 

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  IOCLR1 |= LCD_RS | LCD_R_W;

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  enable();

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  //clear display 

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  IOCLR1 |= LCD_RS | LCD_R_W | LCD_D4 | LCD_D5 | LCD_D6 | LCD_D7; 

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  enable();

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  IOSET1 |= LCD_D4;

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  IOCLR1 |= LCD_RS | LCD_R_W | LCD_D5 | LCD_D6 | LCD_D7; 

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  IOCLR0 |= 0x800;

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  enable();

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  delay_1_53ms();

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  //entry mode set -> increment mode, entire shoft on

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  IOCLR1 |= LCD_RS | LCD_R_W | LCD_D4 | LCD_D5 | LCD_D6 | LCD_D7; 

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  enable();

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  IOSET1 |= LCD_D4 | LCD_D5 | LCD_D6;

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  IOCLR1 |= LCD_RS | LCD_R_W | LCD_D7; 

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  enable();

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  //write 'A' to the display

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  IOSET1 |= LCD_RS | LCD_D6;

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  IOCLR1 |= LCD_R_W | LCD_D4 | LCD_D5 | LCD_D7;

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  enable();

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  IOSET1 |= LCD_RS | LCD_D4;

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  IOCLR1 |= LCD_R_W | LCD_D5 | LCD_D6 | LCD_D7;

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  enable();  

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  while(1);

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}

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void enable(void)

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{

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  delay_39us();

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  IOSET1 |= LCD_E;

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  delay_39us();

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  IOCLR1 |= LCD_E;  

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}

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void delay_30ms(void)

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{

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  unsigned int i=0, j=0;

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  for(i=0; i < 250000; i++)       //250000

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    j+=1;

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}

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void delay_1_53ms(void)

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{

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  unsigned int i=0, j=0;

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  for(i=0; i < 1500; i++)   //1500

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    j+=1;

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}

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void delay_39us(void)

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{

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  unsigned int i=0, j=0;

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  for(i=0; i < 350; i++)      //350

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    j+=1;

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}