#include <stdio.h>
#include <dos.h>
#include "v25.h"

/* #define CHECK_BUSYFLAG */
#define  TEXTLCD      0x7A00		/* TEXT LCD Address */

/* TEXT LCD Instruction Set and Timimg Parameters (WRITE Control Register) */

#define CLS		0x01	/* Clear LCD -- 1.64ms */
#define RET_HOME	0x02	/* Return to Original Position -- 1.64ms */
#define ENTRYMODE	0x04	/* Entry Mode -- 40us */
#define	  EM_INC	0x02		/* Cursor Increment */
#define	  EM_DEC	0x00		/*	  Decrement */
#define   EM_SHIFT	0x01		/* Accompanies DIsplay Shift */
#define DISPLAYCONTROL	0x08	/* Display Control -- 40us */
#define   DC_ON		0x04		/* Display ON */
#define   DC_CURSOR	0x02		/* Cursor ON */
#define   DC_BLINK	0x01		/* Cursor Blink ON */
#define SHIFTMODE	0x10	/* Cursor or Display Shift -- 40us */
#define   SM_DISPLAY	0x08		/* DIsplay Shift */
#define   SM_CURSOR	0x00		/* Cursor Shift */
#define   SM_RIGHT	0x04		/* Shift Right */
#define   SM_LEFT	0x00		/* Shift Left */
#define FUNCTIONSET	0x20	/* Function Set */
#define   FS_8BIT	0x10		/* 8 Bit Mode */
#define   FS_4BIT	0x00		/* 4 Bit Mode */
#define   FS_2LINE	0x08		/* 2 Lines */
#define   FS_1LINE	0x00		/* 1 Line */
#define   FS_5x10	0x04		/* 5 x 10 Dots */
#define   FS_5x7	0x00		/* 5 x 7 Dots */
#define SET_CG_ADDR	0x40	/* Set CGRAM Address -- 40us */
#define SET_ADDRESS	0x80	/* Set DDRAM Address -- 40us */

/* TEXT LCD Status & Address (READ Control Register) */

/*#define CHECK_BUSYFLAG */	/* H/W Support Needed */
#define BUSY_FLAG	0x80	/* Busy Flag */

/* Port 0 - Bit Assignment */

#define TLCD_MASK	0xC0	/* Bits for TLCD */
#define TLCD_DATA	0x40	/* Bit 6 - 1 : data, 0 : Control */
#define TLCD_CTRL	0x00
#define TLCD_E		0x80	/* Bit 7 - 1 : Enable */

#define TLCD_SIZE	0x28
#define TLCD2_BASE	0x40

#define TLCDMODE	(FUNCTIONSET | FS_8BIT | FS_2LINE | FS_5x7)
#define DIS_ON		0x0F	/* LCD ON, Cursor-Blink ON -- 40us */
#define TLCD_DIR	0x06	/* Cursor Increase */
#define TLCD_SHIFT	0x14	/* Move cursor, right */

#define CURSOR_ON	0x0F
#define CURSOR_OFF	0x0C

int TLCD_INITed = 0;

void
delay_4ms(void)
{
	int i;
	for (i = 0; i < 10000; i++)
		;
}

void
TLCD_wait(void)
{
#ifdef CHECK_BUSYFLAG
	unsigned char other, status;

	other = peekb(V25_IRAM, V25_P0) & ~TLCD_MASK;  /* Read Current P0 */
	do {
		pokeb(V25_IRAM, V25_P0, other | TLCD_CTRL);
		pokeb(V25_IRAM, V25_P0, other | TLCD_CTRL | TLCD_E);
		status = inportb(TEXTLCD);
		pokeb(V25_IRAM, V25_P0, other | TLCD_CTRL);
	} while (status & BUSY_FLAG)
		;
#else
	int i;
	for (i = 0; i < 500; i++)
		;
#endif
}

void
TLCD_data(unsigned char data)
{
	unsigned char other;

	other = peekb(V25_IRAM, V25_P0) & ~TLCD_MASK;	/* Read Current P0 */
	pokeb(V25_IRAM, V25_P0, other | TLCD_DATA);
	pokeb(V25_IRAM, V25_P0, other | TLCD_DATA | TLCD_E);
	outportb(TEXTLCD, data);		 	/* send command */
	pokeb(V25_IRAM, V25_P0, other | TLCD_DATA);
	TLCD_wait();
}

void
TLCD_control(unsigned char control)
{
	unsigned char other;

	other = peekb(V25_IRAM, V25_P0) & ~TLCD_MASK;  /* Read Current P0 */
	pokeb(V25_IRAM, V25_P0, other | TLCD_CTRL);
	pokeb(V25_IRAM, V25_P0, other | TLCD_CTRL | TLCD_E);
	outportb(TEXTLCD, control);
	pokeb(V25_IRAM, V25_P0, other | TLCD_CTRL);
	if (TLCD_INITed)
		TLCD_wait();
}

void
TLCD_putch(unsigned location, char ch)
{
	if (location >= TLCD_SIZE)
		location += (TLCD2_BASE - TLCD_SIZE);
	TLCD_control(location | SET_ADDRESS);
	TLCD_data(ch);
}

void
TLCD_puts(unsigned char location, char *buf)
{
	while (*buf)
		TLCD_putch(location++, *buf++);
}

void
TLCD_init(void)
{
	pokeb(V25_IRAM, V25_PMC0, 0);       /* Set port 0 Output */
	pokeb(V25_IRAM, V25_PM0, 0);
	TLCD_control(TLCDMODE);	delay_4ms();
	printf(".");
	TLCD_control(TLCDMODE);	delay_4ms();
	printf(".");
	TLCD_control(TLCDMODE);	delay_4ms();
	printf(".");
	TLCD_INITed = 1;

	TLCD_control(TLCDMODE);
	TLCD_control(DISPLAYCONTROL);
	TLCD_control(CLS);
	TLCD_control(DISPLAYCONTROL | DC_ON );
	TLCD_control(ENTRYMODE | EM_INC);
}

void
main(void)
{
	printf("\nTEXT LCD TEST  ");
	TLCD_init();
	printf("LCD Initialize DONE\n");
	TLCD_puts(0,  "Hansung University");
	TLCD_puts(40, "Micro Processor LAB");
}