AVR lcd.c

1. include "lcd.h"

// *********************************************************** // ******************** PUBLIC FUNCTIONS ********************* // ***********************************************************

void lcdInit4(void) { // initialize LCD control & data // lines to output

PORTD = 0b00000001; // pull-up on unused input DDRD = 0b11111110; // set ctrl & data as outputs

delay_ms(50); // - wait 15ms or more // ------------------- CLEARBIT(PORTD, LCD_CTRL_RS); // set RS to "control" CLEARBIT(PORTD, LCD_CTRL_RW); // set R/W to "write" // 4 bit write SETBIT(PORTD, LCD_CTRL_E); // set "E" line // PORTD = (PORTD | 0x30) & 0x3F; // output data, high 4 bits PORTD = (PORTD | 0x20) & 0x2F; // output data, high 4 bits LCD_DELAY; // wait CLEARBIT(PORTD, LCD_CTRL_E); // clear "E" line // ------------------- delay_ms(5); // - wait 4.1ms SETBIT(PORTD, LCD_CTRL_E); // set "E" line LCD_DELAY; // wait CLEARBIT(PORTD, LCD_CTRL_E); // clear "E" line // -------------------

   delay_ms(1);	                        // -  wait 0.1ms

SETBIT(PORTD, LCD_CTRL_E); // set "E" line LCD_DELAY; // wait CLEARBIT(PORTD, LCD_CTRL_E); // clear "E" line // ------------------- while(lcdBusy()) /* wait */ ; // check for not busy

   										// -------------------

PORTD = (PORTD | 0x20) & 0x2F; // output data, high 4 bits SETBIT(PORTD, LCD_CTRL_E); // set "E" line LCD_DELAY; // wait CLEARBIT(PORTD, LCD_CTRL_E); // clear "E" line // ------------------- lcdControlWrite(0x28); // 0x28 - function set (2 rows, 5x8 font) lcdControlWrite(0x08); // 0x08 - display OFF lcdControlWrite(0x01); // 0x01 - clear display lcdControlWrite(0x06); // 0x06 - shift right lcdControlWrite(0x0C); // 0x0C - display ON, cursor OFF

}

// ************************************************************ // ********************** LOCAL FUNCTIONS ********************* // ************************************************************

void lcdControlWrite(unsigned char c_data) // write the CONTROL byte to the display controller { while(lcdBusy()) /* wait here */ ; // wait until LCD not busy or timeout

CLEARBIT(PORTD, LCD_CTRL_RS); // set RS to "control" CLEARBIT(PORTD, LCD_CTRL_RW); // set R/W to "write"

PORTD = (PORTD&0x0F)|(c_data&0xF0); // output data, high 4 bits SETBIT(PORTD, LCD_CTRL_E); // set "E" line LCD_DELAY; // wait CLEARBIT(PORTD, LCD_CTRL_E); // clear "E" line

PORTD = (PORTD&0x0F) | (c_data<<4); // output data, low 4 bits SETBIT(PORTD, LCD_CTRL_E); // set "E" line LCD_DELAY; // wait CLEARBIT(PORTD, LCD_CTRL_E); // clear "E" line }

void lcdDataWrite(unsigned char w_data) // write a DATA byte to the display { while(lcdBusy()) /* wait */ ; // wait until LCD not busy or timeout

SETBIT(PORTD, LCD_CTRL_RS); // set RS to "data" CLEARBIT(PORTD, LCD_CTRL_RW); // set R/W to "write"

PORTD = (PORTD&0x0F) | (w_data&0xF0); // output data, high 4 bits SETBIT(PORTD, LCD_CTRL_E); // set "E" line LCD_DELAY; // wait CLEARBIT(PORTD, LCD_CTRL_E); // clear "E" line

PORTD = (PORTD&0x0F) | (w_data<<4); // output data, low 4 bits SETBIT(PORTD, LCD_CTRL_E); // set "E" line LCD_DELAY; // wait CLEARBIT(PORTD, LCD_CTRL_E); // clear "E" line }

// ak vrati 1, OK // ak vrati 0, vyprsal timeout

volatile unsigned char t_out_LCD; // timeout displeja (krok 1024 us) // krok 1ms unsigned char lcdBusy(void) {

  delay_ms(10);
  return 0;

/* unsigned char pom; t_out_LCD=4; // pockam cca 4ms // wait until LCD busy bit goes to zero // do a read from control register CLEARBIT(LCD_CTRL_PORT, LCD_CTRL_RS); // set RS to "control"

LCD_DATA_PORT |= 0xF0; // set pull-ups to on (4bit) LCD_DATA_DDR &= 0x0F; // set data I/O lines to input (4bit)

SETBIT(LCD_CTRL_PORT, LCD_CTRL_RW); // set R/W to "read" SETBIT(LCD_CTRL_PORT, LCD_CTRL_E); // set "E" line LCD_DELAY; // wait pom= LCD_DATA_PIN&0xF0; // input data, high 4 bits CLEARBIT(LCD_CTRL_PORT, LCD_CTRL_E); // clear "E" line LCD_DELAY; // wait SETBIT(LCD_CTRL_PORT, LCD_CTRL_E); // set "E" line LCD_DELAY; // wait pom|=(LCD_DATA_PIN>>4)&0x0F; // input data, low 4 bits CLEARBIT(LCD_CTRL_PORT, LCD_CTRL_E); // clear "E" line

while ((pom & (1<<LCD_BUSY)) && t_out_LCD ) { SETBIT(LCD_CTRL_PORT, LCD_CTRL_E); // set "E" line LCD_DELAY; // wait pom=LCD_DATA_PIN&0xF0; // input data, high 4 bits CLEARBIT(LCD_CTRL_PORT, LCD_CTRL_E); // clear "E" line LCD_DELAY; // wait SETBIT(LCD_CTRL_PORT, LCD_CTRL_E); // set "E" line LCD_DELAY; // wait pom|=(LCD_DATA_PIN>>4)&0x0F; // input data, low 4 bits CLEARBIT(LCD_CTRL_PORT, LCD_CTRL_E); // clear "E" line }

// leave data lines in input mode so they can be most easily used for other purposes if(t_out_LCD) return 1; // ak vrati 1 timeout OK else return 0; // ak vrati 0 timeout notOK

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}

/* unsigned char lcdControlRead(void) { // read the control byte from the display controller register unsigned char r_data=0;

if(lcdBusyWait()) // wait until LCD not busy or time out { outb(LCD_DATA_PORT, inb(LCD_DATA_PORT)|0xF0); // set pull-ups to on (4bit) outb(LCD_DATA_DDR, inb(LCD_DATA_DDR)&0x0F); // set data I/O lines to input (4bit) CLEARBIT(LCD_CTRL_PORT, LCD_CTRL_RS); // set RS to "control" SETBIT(LCD_CTRL_PORT, LCD_CTRL_RW); // set R/W to "read"

SETBIT(LCD_CTRL_PORT, LCD_CTRL_E); // set "E" line LCD_DELAY; // wait r_data = inb(LCD_DATA_PIN)&0xF0; // input data, high 4 bits CLEARBIT(LCD_CTRL_PORT, LCD_CTRL_E); // clear "E" line LCD_DELAY; // wait SETBIT(LCD_CTRL_PORT, LCD_CTRL_E); // set "E" line LCD_DELAY; // wait r_data |= inb(LCD_DATA_PIN)>>4; // input data, low 4 bits CLEARBIT(LCD_CTRL_PORT, LCD_CTRL_E); // clear "E" line

// leave data lines in input mode so they can be most easily used for other purposes } return r_data; }

unsigned char lcdDataRead(void) { // read a data byte from the display register unsigned char r_data =0;

if(lcdBusyWait()) // wait until LCD not busy or time out { outb(LCD_DATA_PORT, inb(LCD_DATA_PORT)|0xF0); // set pull-ups to on (4bit) outb(LCD_DATA_DDR, inb(LCD_DATA_DDR)&0x0F); // set data I/O lines to input (4bit) SETBIT(LCD_CTRL_PORT, LCD_CTRL_RS); // set RS to "data" SETBIT(LCD_CTRL_PORT, LCD_CTRL_RW); // set R/W to "read"

SETBIT(LCD_CTRL_PORT, LCD_CTRL_E); // set "E" line LCD_DELAY; // wait r_data = inb(LCD_DATA_PIN)&0xF0; // input data, high 4 bits CLEARBIT(LCD_CTRL_PORT, LCD_CTRL_E); // clear "E" line LCD_DELAY; // wait SETBIT(LCD_CTRL_PORT, LCD_CTRL_E); // set "E" line LCD_DELAY; // wait r_data |= inb(LCD_DATA_PIN)>>4; // input data, low 4 bits CLEARBIT(LCD_CTRL_PORT, LCD_CTRL_E); // clear "E" line

} // leave data lines in input mode so they can be most easily used for other purposes return r_data; }

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void delay_ms(unsigned int ms) {

 unsigned int index;

 while (ms)
 {
  index = F_CPU / 5000;    // vypocitajte, kolko treba, aby sme dostali 1ms!!
       
  while (index)
  {
   asm volatile ("nop");
   index--;
  }

  ms--;
 }

}