Admin at 04:15, 26 January 2013

2013-01-26T04:15:06Z

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This page shows the code for directly accessing an attached LCD device (here the 2x16 character lcd device from Jaycar).

<pre>

void Write_LCD_Nibble(unsigned short N, int RS)
{

digitalWrite(STR,0);

// ****** Write RS *********
digitalWrite(CLK,0);
digitalWrite(Dout,RS); // Data_Pin
digitalWrite(CLK,1);
digitalWrite(CLK,0);

// Shift in 4 bits
int t = 0;
int Flag = 0;
int Mask = 8;

for (t=0; t<4; t++)
{
Flag = N & Mask;
if(Flag==0)
{
digitalWrite(Dout,0); // Data_Pin
} else {
digitalWrite(Dout,1); // Data_Pin
}

digitalWrite(CLK,1);
digitalWrite(CLK,0);

Mask = Mask >> 1;
}

// One more clock because SC and ST clks are tied
digitalWrite(CLK,1);
digitalWrite(CLK,0);
digitalWrite(Dout,0); // Data_Pin
digitalWrite(STR,1); // Enable_Pin (to LCD)
digitalWrite(STR,0); // Enable_Pin (to LCD)

}

void Write_LCD_Data(unsigned short D)
{
int RS = 1; // It is Data, not command
int Low_Nibble = D & 15;
int High_Nibble = D/16;
Write_LCD_Nibble(High_Nibble,RS);
Write_LCD_Nibble(Low_Nibble,RS);
}

void Write_LCD_Cmd(unsigned short C)
{

int RS = 0; // It is command, not data
int Low_Nibble = C & 15;
int High_Nibble = C/16;
Write_LCD_Nibble(High_Nibble,RS);
Write_LCD_Nibble(Low_Nibble,RS);
}

void initialise_LCD()
{

pinMode(CLK,0);
pinMode(STR,0);
pinMode(Dout,0);

_delay_ms(100);

Write_LCD_Cmd(0x03); // function set
_delay_ms(50);

Write_LCD_Cmd(0x03);
_delay_ms(50);

Write_LCD_Cmd(0x03);
_delay_ms(50);

Write_LCD_Cmd(0x02);
_delay_ms(50);

Write_LCD_Cmd(0x2C); // Display ON, No cursors
_delay_ms(50);

Write_LCD_Cmd(0x06); // Entry mode- Auto-increment, No Display shifting
_delay_ms(50);

Write_LCD_Cmd(0x0E);
_delay_ms(50);

Write_LCD_Cmd(0x01);
_delay_ms(50);

Write_LCD_Cmd(0x80);
_delay_ms(50);

}

void Position_LCD(unsigned short x, unsigned short y)
{
int temp = 127 + y;

if (x == 2)
{
temp = temp + 64;
}

Write_LCD_Cmd(temp);
}

void Clear_LCD()
{
Write_LCD_Cmd(0x01); // Clear LCD
_delay_ms(5);

}

void Write_LCD_Text(char *StrData)
{

int p = 0;
int q = strlen(StrData);
int temp = 0;

for (p = 0; p < q; p++)
{
temp = StrData[p];
Write_LCD_Data(temp);
}
}

void Write_LCD_Number(char number)
{
// writes a number's digits on the display

int digits;

if (number == 0)
{
digits = 0;
int array[0];
array[0]=0;
Write_LCD_Data(array[0]+48);

} else {

// determine the number of digits
int digits = (int)(log(number)/log(10))+1;

// split up the number to an array
int i = digits - 1;
int array[digits];
while (number > 0)
{
array[i--] = number % 10;
number /= 10;
}

// display array on LCD
for(i = 0; i <= digits-1; i++)
{
Write_LCD_Data(array[i]+48);
}

}

}

</pre>

LCD - Revision history

Admin at 04:15, 26 January 2013