pit.h

一个极小型的操作系统

/*
GazOS Operating System
Copyright (C) 1999  Gareth Owen <[e-mail]>

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/

#ifndef INCLUDE_PIT
#define INCLUDE_PIT

void init_pit(float h, unsigned char channel);
unsigned int pit_getchannel(unsigned char channel);

#define 	TMR_CTRL	0x43	/*	I/O for control		*/
#define		TMR_CNT0	0x40	/*	I/O for counter 0	*/
#define		TMR_CNT1	0x41	/*	I/O for counter 1	*/
#define		TMR_CNT2	0x42	/*	I/O for counter 2	*/

#define		TMR_SC0		0	/*	Select channel 0 	*/
#define		TMR_SC1		0x40	/*	Select channel 1 	*/
#define		TMR_SC2		0x80	/*	Select channel 2 	*/

#define		TMR_LOW		0x10	/*	RW low byte only 	*/
#define		TMR_HIGH	0x20	/*	RW high byte only 	*/
#define		TMR_BOTH	0x30	/*	RW both bytes 		*/

#define		TMR_MD0		0	/*	Mode 0 			*/
#define		TMR_MD1		0x2	/*	Mode 1 			*/
#define		TMR_MD2		0x4	/*	Mode 2 			*/
#define		TMR_MD3		0x6	/*	Mode 3 			*/
#define		TMR_MD4		0x8	/*	Mode 4 			*/
#define		TMR_MD5		0xA	/*	Mode 5 			*/

#define		TMR_BCD		1	/*	BCD mode 		*/

#define		TMR_LATCH	0	/*	Latch command 		*/

#define		TMR_READ	0xF0	/*    Read command 		*/
#define		TMR_CNT		0x20	/*    CNT bit  (Active low, subtract it) */
#define		TMR_STAT	0x10	/*    Status bit  (Active low, subtract it) */
#define		TMR_CH2		0x8	/*    Channel 2 bit 		*/
#define		TMR_CH1		0x4	/*    Channel 1 bit 		*/
#define		TMR_CH0		0x2	/*    Channel 0 bit 		*/

#endif