pit.h

// file: "pit.h"

// Copyright (c) 2001 by Marc Feeley and Universit? de Montr?al, All
// Rights Reserved.
//
// Revision History
// 22 Sep 01  initial version (Marc Feeley)

#ifndef __PIT_H
#define __PIT_H

//-----------------------------------------------------------------------------

#include "general.h"

//-----------------------------------------------------------------------------

//
// Definitions for 8254 programmable interval timer.
//

#define PIT1_PORT_BASE 0x40
#define PIT2_PORT_BASE 0x48

#define PIT_PORT_CTR(n, base) ((n) + (base))
#define PIT_PORT_CW(base) (3 + (base))

#define PIT_CW_CTR(n) ((n) << 6)
#define PIT_CW_READ_BACK (3 << 6)
#define PIT_CW_CTR_LATCH (0 << 4)
#define PIT_CW_LSB (1 << 4)
#define PIT_CW_MSB (2 << 4)
#define PIT_CW_LSB_MSB (3 << 4)
#define PIT_CW_MODE(n) ((n) << 1)
#define PIT_CW_BCD (1 << 0)

#define PIT_COUNTS_PER_SEC 1193182 // clock frequency at input of PIT1 and PIT2

//-----------------------------------------------------------------------------

#endif

// Local Variables: //
// mode: C++ //
// End: //