lcd_driver.c

一个LCD驱动程序

//*****************************************************************************
//
//  File........: LCD_driver.c
//
//  Author(s)...: ATMEL Norway
//
//  Target(s)...: ATmega169
//
//  Compiler....: IAR EWAAVR 2.27b
//
//  Description.: Functions used to control the STK502 LCD
//
//  Revisions...: 1.0
//
//  YYYYMMDD - VER. - COMMENT                                       - SIGN.
//
//  20021015 - 1.0  - General modifications and clean up            - JLL
//
//*****************************************************************************


// Include files.
#include "Main.h"
#include "LCD_driver.h"


union _LCD_status LCD_status = {0x01};    //LCD_status = {0, 0, 0, 0, 0, 0, FALSE, TRUE}; 
unsigned char LCD_timer = LCD_TIMER_SEED;

unsigned char LCD_displayData[LCD_REGISTER_COUNT];		// LCD display buffer (for double buffering).

// Look-up table used when converting ASCII to LCD display data	(segment control)
__flash unsigned int LCD_character_table[] = // Character definitions table.
{
	0x0A51,		// '*' (?)
	0x2A80,		// '+'
	0x0000,		// ',' (Not defined)
	0x0A00,		// '-'
	0x0A51,		// '.' Used in the Application Note AVR064, to write "degree" in the display
	0x0000,		// '/' (Not defined)
	0x5559,		// '0'
	0x0118,		// '1'
	0x1e11,
	0x1b11,
	0x0b50,
	0x1b41,
	0x1f41,
	0x0111,
	0x1f51,
	0x1b51,		// '9'
	0x0000,		// ':' (Not defined)
	0x0000,		// ';' (Not defined)
	0x0000,		// '<' (Not defined)
	0x0000,		// '=' (Not defined)
	0x0000,		// '>' (Not defined)
	0x0000,		// '?' (Not defined)
	0x0000,		// '@' (Not defined)
	0x0f51,		// 'A' (+ 'a')
	0x3991,		// 'B' (+ 'b')
	0x1441,		// 'C' (+ 'c')
	0x3191,		// 'D' (+ 'd')
	0x1e41,
	0x0e41,
	0x1d41,
	0x0f50,
	0x2080,
	0x1510,
	0x8648,
	0x1440,
	0x0578,
	0x8570,
	0x1551,
	0x0e51,
	0x9551,
	0x8e51,
	0x9021,
	0x2081,
	0x1550,
	0x4448,
	0xc550,
	0xc028,
	0x2028,		// 'Y' (+ 'y')
	0x5009,		// 'Z' (+ 'z')
	0x0000,		// '[' (Not defined)
	0x0000,		// '\' (Not defined)
	0x0000,		// ']' (Not defined)
	0x0000,		// '^' (Not defined)
	0x0000		// '_' (Not defined)
};


/******************************************************************************************
*
*	Function name : LCD_Init
*
*	Returns :		None
*
*	Parameters :	None
*
*	Purpose :		Initialize LCD_displayData buffer. Set up the LCD (timing, contrast, etc.)
*
******************************************************************************************/
void LCD_Init (void)
{
	LCD_AllSegments( FALSE );	// Clear segment buffer.
	LCDCRA = (1<<LCDEN);		// Enable LCD.

    LCD_CONTRAST_LEVEL(LCD_INITIAL_CONTRAST);    //Set the LCD contrast level

	// Select asynchronous clock source, enable all COM pins and enable all segment pins.
	LCDCRB = (1<<LCDCS) | (1<<LCDMUX1) | (1<<LCDMUX0) | (1<<LCDPM2) | (1<<LCDPM1)| (1<<LCDPM0); 
	LCDFRR = (1<<LCDPS0);                       // Set LCD prescaler to CLK(lcd)/64 = 64Hz.

	LCDCRA |= (1<<LCDIE);	                    //Enable LCD_Start_frame interrupt
}

/******************************************************************************************
*
*	Function name : LCD_WriteDigit( unsigned char c, unsigned char digit )
*
*	Returns :		None
*
*	Parameters :	Inputs 
*                    c - The symbol to be displayed in a LCD digit
*                    digit - The LCD digit that the symbol should be displayed in
*
*	Purpose :		Stores LCD control data in the LCD_displayData buffer.
*                   (The LCD_displayData is latched in the LCD_SOF interrupt).
*
******************************************************************************************/
void LCD_WriteDigit( unsigned char c, unsigned char digit )
{

	unsigned int seg;
	unsigned char i;
	unsigned char mask, nibble;
	unsigned char *ptr;

	//Lookup character table for segmet data
	seg = 0x0000;
	if ( (c >= '*') && (c <= 'z') )
	{
		// c is in character_table.
		// Convert to upper if necessarry.
		if ( c >= 'a' ) c &= ~0x20;
		c -= '*';
		seg = LCD_character_table[c];
	}

	// Adjust mask according to digit
	mask = 0x0F;		// (1), 3, 5, 7
	if ( digit & 0x01 )
	{
	}
	else
	{
		mask = 0xF0;		// (0), 2, 4, 6
	}

	i = digit-2;
	if ( i >= 6 )
		return;
	i >>= 1;
	ptr = LCD_displayData + i;		// i = {0,0,1,1,2,2}

	i = 4;
	do
	{
		nibble = seg & 0x000F;
		seg >>= 4;
		if ( digit & 0x01 )
			nibble <<= 4;
		*ptr = (*ptr & mask) | nibble;
		ptr += 5;
	} while ( --i );
}


/******************************************************************************************
*
*	Function name : LCD_AllSegments( unsigned char input )
*
*	Returns :		None
*
*	Parameters :	Inputs->
*                     input -  [TRUE;FALSE]=[DISPLAY;HIDE]
*
*	Purpose :		display all or hide all LCD segments on the STK502 LCD
*
******************************************************************************************/
void LCD_AllSegments( unsigned char input )
{
	unsigned char i;
	unsigned char *ptr;

	if( input )				    // if input == TRUE
		input = 0xFF;			// set setgemts to 0xFF
								// (else set segments to 0x00)
	
	ptr = LCD_displayData;
	i = 20;
	do							// Set all LCD segment register to the variable Segments
	{
		*ptr++ = input;		// Set/clear the bits in all LCD registers
	} while ( --i );
}


/******************************************************************************
*
*   LCD Interrupt Routine
*
*	Returns :		None
*
*	Parameters :	None
*
*   Purpose: Latch the LCD_displayData and Set LCD_status.updateComplete
*
*******************************************************************************/
#pragma vector = LCD_SOF_vect
__interrupt void LCD_SOF_interrupt( void )
{
	unsigned char i;
	unsigned char *src, *dest;

	LCD_timer--;
	if( LCD_timer == 0 )    // if time out
	{
	    if( LCD_status.updateRequired == TRUE )
		{
			LCD_timer = LCD_TIMER_SEED;         // Reload the LCD_timer
			LCD_status.updateComplete = TRUE;	// Set the LCD_ScrollReady to true.
			LCD_status.blinkLCD = ~LCD_status.blinkLCD;		// Toggle LCD_Blink variable.

			// Copy display data buffer to I/O segment registers.
			i = 20;
			dest = &pLCDREG;
			src = LCD_displayData;
			do
			{
				*dest++ = *src++;
			} while ( --i );
		}
		else
		{
		  LCD_timer = 1;              //If LCD timer allows update of the LCD, but update is blocked
		                              // by LCD_status.updateRequired == FALSE the LCD_timer is preloaded
		                              // with smallest timer seed to ensure fastest LCD update.
          LCD_status.updateComplete = FALSE;  //Block for further access to the LCD_displayData until
                                              // LCD update has been performed.
		}
	}
}