timer.h

this is for 8051 analog document

/* File: TIMER.H
** Description:
**   Constants and declarations for use with TIMER.C.
** Copyright:
**   Copyright 1994, David G. Roberts
*/

#ifndef _TIMER_H

#include "gamedefs.h"

/* CONSTANTS */
/* counter port addresses */
#define COUNTER_0		0x40
#define COUNTER_1		0x41
#define COUNTER_2		0x42
#define COUNTER_MODE	0x43

/* mode control bit definitions */
/* select bits (bits 7 & 6) */
#define SELECT_0		0x00
#define	SELECT_1		0x40
#define SELECT_2		0x80
#define READ_BACK		0xC0
#define SELECT_MASK		0xC0

/* read/write/latch bits (bits 5 & 4) */
#define LATCH_CNTR		0x00
#define RW_MSB			0x10
#define RW_LSB			0x20
#define RW_LSB_MSB		0x30
#define RWL_MASK		0x30

/* counter mode bits (bits 3, 2, & 1) */
#define MODE_EVENT			0x00
#define MODE_ONE_SHOT		0x02
#define MODE_DIV_N			0x04
#define MODE_SQUARE_WAVE	0x06
#define MODE_SW_STROBE		0x08
#define MODE_HW_STROBE		0x0A
#define MODE_MASK			0x0E

/* counter type bit (bit 0) */
#define TYPE_BINARY		0x00
#define TYPE_BCD		0x01
#define TYPE_MASK		0x01

void ProgramTimer(UINT8 Mode, UINT16 Count);
UINT16 ReadTimerCount(int Timer);
void far interrupt (*HookAndProgramSysTimer
	(
	void far interrupt (*Address)(),
    UINT8 Mode,
	UINT16 Count
	))();
void RestoreSysTimer(void);
void UnhookAndRestoreSysTimer(void far interrupt (*Address)());
void RestoreDOSTime(void);

#define _TIMER_H

#endif