#include "LCD4bit.h"
// ---------------------------------------------------------------------------
// INCLUDES
#include <avr/io.h> // deal with port registers
#include <util/delay.h> // used for _delay_ms function
#include <string.h> // string manipulation routines
#include <stdlib.h>
// ---------------------------------------------------------------------------
// TYPEDEFS
typedef uint8_t byte; // I just like byte & sbyte better
typedef int8_t sbyte;
// ---------------------------------------------------------------------------
// MISC ROUTINES
void SetupPorts()
{
DDRB = 0x3F; // 0011.1111; set B0-B5 as outputs
DDRC = 0x00; // 0000.0000; set PORTC as inputs
}
void msDelay(int delay) // put into a routine
{ // to remove code inlining
for (int i=0;i<delay;i++) // at cost of timing accuracy
_delay_ms(1);
}
// ---------------------------------------------------------------------------
// HD44780-LCD DRIVER ROUTINES
//
// Routines:
// LCD_Init initializes the LCD controller
// LCD_Cmd sends LCD controller command
// LCD_Char sends single ascii character to display
// LCD_Clear clears the LCD display & homes cursor
// LCD_Home homes the LCD cursor
// LCD_Goto puts cursor at position (x,y)
// LCD_Line puts cursor at start of line (x)
// LCD_Hex displays a hexadecimal value
// LCD_Integer displays an integer value
// LCD_Message displays a string
//
// The LCD module requires 6 I/O pins: 2 control lines & 4 data lines.
// PortB is used for data communications with the HD44780-controlled LCD.
// The following defines specify which port pins connect to the controller:
#define LCD_RS 0 // pin for LCD R/S (eg PB0)
#define LCD_E 1 // pin for LCD enable
#define DAT4 2 // pin for d4
#define DAT5 3 // pin for d5
#define DAT6 4 // pin for d6
#define DAT7 5 // pin for d7
// The following defines are HD44780 controller commands
#define CLEARDISPLAY 0x01
#define SETCURSOR 0x80
void PulseEnableLine ()
{
SetBit(PORTB,LCD_E); // take LCD enable line high
_delay_us(40); // wait 40 microseconds
ClearBit(PORTB,LCD_E); // take LCD enable line low
}
void SendNibble(byte data)
{
PORTB &= 0xC3; // 1100.0011 = clear 4 data lines
if (data & _BV(4)) SetBit(PORTB,DAT4);
if (data & _BV(5)) SetBit(PORTB,DAT5);
if (data & _BV(6)) SetBit(PORTB,DAT6);
if (data & _BV(7)) SetBit(PORTB,DAT7);
PulseEnableLine(); // clock 4 bits into controller
}
void SendByte (byte data)
{
SendNibble(data); // send upper 4 bits
SendNibble(data<<4); // send lower 4 bits
ClearBit(PORTB,5); // turn off boarduino LED
}
void LCD_Cmd (byte cmd)
{
ClearBit(PORTB,LCD_RS); // R/S line 0 = command data
SendByte(cmd); // send it
}
void LCD_Char (byte ch)
{
SetBit(PORTB,LCD_RS); // R/S line 1 = character data
SendByte(ch); // send it
}
void LCD_Init()
{
LCD_Cmd(0x33); // initialize controller
LCD_Cmd(0x32); // set to 4-bit input mode
LCD_Cmd(0x28); // 2 line, 5x7 matrix
LCD_Cmd(0x0C); // turn cursor off (0x0E to enable)
LCD_Cmd(0x06); // cursor direction = right
LCD_Cmd(0x01); // start with clear display
msDelay(3); // wait for LCD to initialize
}
void LCD_Clear() // clear the LCD display
{
LCD_Cmd(CLEARDISPLAY);
msDelay(3); // wait for LCD to process command
}
void LCD_Home() // home LCD cursor (without clearing)
{
LCD_Cmd(SETCURSOR);
}
void LCD_Goto(byte x, byte y) // put LCD cursor on specified line, row
{
byte addr = 0; // line 0 begins at addr 0x00
switch (x)
{
case 1: addr = 0x80; break; // line 1 begins at addr 0x40
case 2: addr = 0xC0; break;
}
LCD_Cmd(addr+y); // update cursor with x,y position
}
void LCD_Line(byte row) // put cursor on specified line
{
LCD_Goto(0,row);
}
void LCD_Message(const char *text) // display string on LCD
{
while (*text) // do until /0 character
LCD_Char(*text++); // send char & update char pointer
}
void LCD_Hex(int data)
// displays the hex value of DATA at current LCD cursor position
{
char st[8] = ""; // save enough space for result
itoa(data,st,16); // convert to ascii hex
//LCD_Message("0x"); // add prefix "0x" if desired
LCD_Message(st); // display it on LCD
}
void LCD_Integer(int data)
// displays the integer value of DATA at current LCD cursor position
{
char st[8] = ""; // save enough space for result
itoa(data,st,10); // convert to ascii
LCD_Message(st); // display in on LCD
}
// ---------------------------------------------------------------------------
// DEMO FUNCTIONS
void UpdateCursor (byte count) // helper fn for FillScreen
{
switch(count)
{
case 0: LCD_Line(0); break;
case 16: LCD_Line(1); break;
case 32: LCD_Line(2); break;
case 48: LCD_Line(3); break;
}
}
char GetNextChar(char ch) // helper fn for FillScreen
{
if ((ch<0x20) | (ch>=0xFF))
return 0x20;
if ((ch>=0x7F) & (ch<0xA0))
return 0xA0;
return ++ch;
}
#define NUMCHARS 64 // number of characters per screen
void FillScreen ()
// fills LCD screen with ascii characters
// be sure to set NUMCHARS to 32 or 64 characters, depending on the size of your display
// 32 looks good on 16x2 displays; 64 looks good on 20x4 displays.
// four line displays also show an incrementing 1-99 page counter.
{
char ch = 'A';
LCD_Clear();
for (byte count=1;count<100;count++)
{
LCD_Goto(18,0);
LCD_Integer(count); // show counter (vis on 4-liners only)
for (byte i=0;i<NUMCHARS;i++) // do a screenful of characters
{
UpdateCursor(i); // go to next line, if necessary
LCD_Char(ch); // show current ascii character
ch = GetNextChar(ch); // update to next character
msDelay(60); // set animation speed
}
}
}
// ---------------------------------------------------------------------------
// MAIN PROGRAM
int main(void)
{
SetupPorts(); // use PortB for LCD interface
LCD_Init(); // initialize LCD controller
LCD_Message("Ready."); // welcome message
msDelay(2000); // wait
while(1)
FillScreen(); // fill screen with ASCII characters
}
