#include "t6963lcd.h"

#define     UC              unsigned char

void lcd_init(void);
void lcd_cls(void);
void lcd_putchar(UC achr);
void lcd_cmd(UC cmd);
void lcd_cmd1(UC cmd, UC arg1);
void lcd_cmd2(UC cmd, UC arg1, UC arg2);
void lcd_gotoxy(UC x, UC y);


// LCD IO mapping

xdata at LCD_CMDPORT UC lcd_cmdreg;
xdata at LCD_DATAPORT UC lcd_datareg;

// Global display status registers

data at 0x30 lcd_dx;             // Two registers in internal data ram that
data at 0x31 lcd_dy;             // should'nt be overwritten. These registers
// indicates the insert location on display


/************************************************************************************
 *Test code
************************************************************************************/

void main(void) {
    lcd_init();

    lcd_putchar('H');
    lcd_putchar('E');
    lcd_putchar('L');
    lcd_putchar('L');
    lcd_putchar('O');

    lcd_putchar('\n');
    lcd_putchar('L');
    lcd_putchar('C');
    lcd_putchar('D');
    lcd_putchar(' ');
    lcd_putchar('O');
    lcd_putchar('K');

    while (1);
}


/************************************************************************************
 * Lcd functions
************************************************************************************/

// Waits for controller to accept command

void lcd_wait_ready(void)  {

    while ((lcd_cmdreg & 3) != 3);
}

// Writes a command without paramerers to contoller

void lcd_cmd(UC cmd) {

    lcd_wait_ready();
    lcd_cmdreg = cmd;
}


// Writes a command with one parameter to contoller

void lcd_cmd1(UC cmd, UC arg1) {
    lcd_wait_ready();
    lcd_datareg = arg1;
    lcd_wait_ready();
    lcd_cmdreg = cmd;
}


// Writes a command with two parameters to contoller

void lcd_cmd2(UC cmd, UC arg1, UC arg2) {

    lcd_wait_ready();
    lcd_datareg = arg1;
    lcd_wait_ready();
    lcd_datareg = arg2;
    lcd_wait_ready();
    lcd_cmdreg = cmd;
}


// Filling display with ' '

void lcd_cls(void) {
    unsigned int i;

    lcd_cmd2(LCD_ADPSET, LCD_TEXT_MEM & 255, LCD_TEXT_MEM >> 8);

    lcd_cmd(LCD_AWRON);            		// Enable autowriting

    for (i = 0; i != (LCD_TEXT_WIDTH * LCD_TEXT_HEIGHT); i++) {
        while (!(lcd_cmdreg &  8)); 			// Check autowrite flag
        lcd_datareg = 0;
    }

    lcd_cmd(LCD_AWROFF);           		// Disable autowriting
    lcd_cmd2(LCD_ADPSET, LCD_TEXT_MEM & 255, LCD_TEXT_MEM >> 8);

    lcd_dx = lcd_dy = 0;
}

// Initializes controller and setting parameters

void lcd_init(void) {
    lcd_cmd2(LCD_TXHOME, LCD_TEXT_MEM & 255, LCD_TEXT_MEM >> 8);
    lcd_cmd2(LCD_GRHOME, LCD_GRAPH_MEM & 255, LCD_GRAPH_MEM >> 8);

    lcd_cmd2(LCD_TXAREA, LCD_TEXT_WIDTH, 0);
    lcd_cmd2(LCD_GRAREA, LCD_TEXT_WIDTH, 0);
    lcd_cmd2(LCD_OFFSET,  3, 0);

    lcd_cmd2(LCD_ADPSET, LCD_TEXT_MEM & 255, LCD_TEXT_MEM >> 8);

    lcd_cmd(0x80);               			// Internal character generator
    lcd_cmd(0x94);               			// Text: ON, Graphic: OFF, Cursor: OFF
    lcd_cls();                   			// Clears display

}


// Changes the instert location

void lcd_gotoxy(UC x, UC y) {

    unsigned int temp;

    lcd_dx = x;
    lcd_dy = y;


    temp = (y * LCD_TEXT_WIDTH + x) + LCD_TEXT_MEM;

    lcd_cmd2(LCD_ADPSET, temp & 255, temp >> 8);

}


// Writes an ascii char to display

void lcd_putchar(UC achr) {

    if (achr == '\n') lcd_gotoxy(0,lcd_dy+1);

    else lcd_cmd1(LCD_WRINC, achr - 0x20);

}