#include <stdio.h>
#include <dos.h>
#include <conio.h>

#include "v25.h"     /*v25¿ë Header File */

#define  YES  1
#define  NO   0

void
delay_10(void)
{
	int i, j;
	for (i =0 ; i < 12; i++)
		for(j = 0; j < 5000; j++)
			;
}

volatile int interval_flag; /* Variable changed by ISR */
volatile int brightness;  /* -> always read real-memory, not in register */

void
bright_control(void)
{
	int i, tmp;

	printf("\nPress Any Key to Stop ");
	interval_flag=NO;
	for (i = 0; i < 200; i++) {
		/* Wait Another Timer Period */
		while(interval_flag != YES)
			;
		disable();  /* Disable Interrupt */
		interval_flag = NO;
		tmp = brightness;
		brightness = i / 20;
		if (tmp != brightness)
			printf("\n Brightness = %d", brightness);
		enable();   /* Enable Interrupt */

		if (kbhit()) {
			getch();
			break;
		}
	}
}

void
interrupt
new_int1Ch(void)
{
	/* TURBO_C does complex interrupt stuffs */

	static int timer_count = 0;
	enable();			/* Enable Higher Priority Interrupt */
	timer_count++;

	if (timer_count >= 10) {
		timer_count = 0;
		interval_flag = YES;
	}
	if (timer_count < brightness)
		pokeb(V25_IRAM,V25_P0,0x00);
	else
		pokeb(V25_IRAM,V25_P0,0xFF);
}

void
main(void)
{
	void interrupt (*old_int1Ch)();  /* Old Interrupt ISR */

	pokeb(V25_IRAM, V25_PMC0, 0x0);	/* V25 port 0 => OUTPUT  */
	pokeb(V25_IRAM, V25_PM0, 0x0);

	old_int1Ch = getvect(0x1C);	/* Save Original ISR */
	setvect(0x1C,new_int1Ch);	/* Set New Vector */

	bright_control();

	setvect(0x1C,old_int1Ch);	/* Restore Origianl Vector */

	printf("\nLED ");
	printf("ON ");  pokeb(V25_IRAM, V25_P0, 0x00); delay_10();
	printf("OFF "); pokeb(V25_IRAM, V25_P0, 0xFF); delay_10();
	printf("ON ");  pokeb(V25_IRAM, V25_P0, 0x00); delay_10();
	printf("\n");
}