DIRECT HARDWARE ACCESS - DOS
// File...: RTCTEST.C (c) SSV SOFTWARE SYSTEMS 1998
// Version: 1.00 (Build 2 - 16 Bit DOS)
// Date...: 27.Jul.1998
// *** DISCLAIMER OF WARRENTY ***
// =======================================================
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT
// A WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
// Typedefs
typedef unsigned char BYTE;
typedef unsigned int WORD;
// Includes
#include ‹stdlib.h›
#include ‹stdio.h›
#include ‹graphics.h›
#include ‹conio.h›
#include ‹dos.h›
#include ‹bios.h›
#include ‹string.h›
// Defines
#ifdef __cplusplus
#define __CPPARGS ...
#else
#define __CPPARGS
#endif
#define ID_TIMER 1 // Timer ID
#define RTC_AdrPort 0x70 // I/O Addr. RTC Addr. Port
#define RTC_DataPort 0x71 // I/O Addr. RTC Data Port
#define RTC_Seconds 0x00 // AddrIndex RTC Seconds
#define RTC_SecondsAlarm 0x01 // AddrIndex RTC Seconds Alarm
#define RTC_Minutes 0x02 // AddrIndex RTC Minutes
#define RTC_MinutesAlarm 0x03 // AddrIndex RTC Minutes Alarm
#define RTC_Hours 0x04 // AddrIndex RTC Hours
#define RTC_HoursAlarm 0x05 // AddrIndex RTC Hours Alarm
#define RTC_DayOfWeek 0x06 // AddrIndex RTC Day of Week
#define RTC_DateOfMonth 0x07 // AddrIndex RTC Date of Month
#define RTC_Month 0x08 // AddrIndex RTC Month
#define RTC_Year 0x09 // AddrIndex RTC Year
#define RTC_RegisterA 0x0a // AddrIndex RTC RegisterA
#define RTC_RegisterB 0x0b // AddrIndex RTC RegisterB
#define RTC_RegisterC 0x0c // AddrIndex RTC RegisterC
#define RTC_RegisterD 0x0d // AddrIndex RTC RegisterD
#define MASTER_PIC 0x20 // Base Addr. Master PIC
#define SLAVE_PIC 0xa0 // Base Addr. Slave PIC
#define EOI 0x20 // PIC EndOfInterrupt Command
#define IRQ1 1 // Interrupt Request 1
#define IRQ2 2 // Interrupt Request 2
#define IRQ3 3 // Interrupt Request 3
#define IRQ4 4 // Interrupt Request 4
#define IRQ5 5 // Interrupt Request 5
#define IRQ6 6 // Interrupt Request 6
#define IRQ7 7 // Interrupt Request 7
#define IRQ8 8 // Interrupt Request 8
#define IRQ9 9 // Interrupt Request 9
#define IRQ10 10 // Interrupt Request 10
#define IRQ11 11 // Interrupt Request 11
#define IRQ12 12 // Interrupt Request 12
#define IRQ13 13 // Interrupt Request 13
#define IRQ14 14 // Interrupt Request 14
#define IRQ15 15 // Interrupt Request 15
// Globals
long glIrq8Counter= 0l;
void interrupt (*oldIRQ8Handler) (__CPPARGS);
// Internal Function Prototyps
BYTE ReadPort (WORD);
void WritePort (WORD, BYTE);
void SendEOI (BYTE);
void EnableIRQ (BYTE);
void DisableIRQ (BYTE);
void SetIRQ (BYTE, void interrupt (*) ());
void interrupt IRQ8Handler (__CPPARGS);
BYTE ReadTimeByte (BYTE);
BYTE ReadRTC (WORD);
void WriteRTC (WORD, BYTE);
void main ();
//***************************************************************************
BYTE ReadPort (WORD wPortAddr)
{
return (inportb (wPortAddr));
}
//***************************************************************************
void WritePort (WORD wPortAddr, BYTE bData)
{
outportb (wPortAddr, bData);
}
//***************************************************************************
void SendEOI (BYTE bIrqNumber)
{
if (bIrqNumber › 7) WritePort (SLAVE_PIC, EOI);
WritePort (MASTER_PIC, EOI);
}
//***************************************************************************
void EnableIRQ (BYTE bIrqNumber)
{
int nPort;
// Build PIC Mask Port Addr. (BaseAddr + 1)...
nPort= (bIrqNumber ‹= 7) ? MASTER_PIC : SLAVE_PIC;
nPort++;
bIrqNumber &= 0x0007;
WritePort (nPort, ReadPort (nPort) & ~(1 ‹‹ bIrqNumber));
}
//***************************************************************************
void DisableIRQ (BYTE bIrqNumber)
{
int nPort;
// Build PIC Mask Port Addr. (BaseAddr + 1)...
nPort= (bIrqNumber ‹= 7) ? MASTER_PIC : SLAVE_PIC;
nPort++;
bIrqNumber &= 0x0007;
WritePort (nPort, ReadPort (nPort) | (1 ‹‹ bIrqNumber));
}
//***************************************************************************
void SetIRQ (BYTE bIrqNumber, void interrupt (*IrqHandler) (__CPPARGS))
{
switch (bIrqNumber) {
case IRQ1 : setvect (0x09, IrqHandler); break;
case IRQ2 : setvect (0x0a, IrqHandler); break;
case IRQ3 : setvect (0x0b, IrqHandler); break;
case IRQ4 : setvect (0x0c, IrqHandler); break;
case IRQ5 : setvect (0x0d, IrqHandler); break;
case IRQ6 : setvect (0x0e, IrqHandler); break;
case IRQ7 : setvect (0x0f, IrqHandler); break;
case IRQ8 : setvect (0x70, IrqHandler); break;
case IRQ9 : setvect (0x71, IrqHandler); break;
case IRQ10: setvect (0x72, IrqHandler); break;
case IRQ11: setvect (0x73, IrqHandler); break;
case IRQ12: setvect (0x74, IrqHandler); break;
case IRQ13: setvect (0x75, IrqHandler); break;
case IRQ14: setvect (0x76, IrqHandler); break;
case IRQ15: setvect (0x77, IrqHandler); break;
default : break;
}
}
//***************************************************************************
void interrupt IRQ8Handler (__CPPARGS)
{
glIrq8Counter++;
ReadRTC (RTC_RegisterC);
SendEOI (IRQ8);
}
//***************************************************************************
BYTE ReadTimeByte (BYTE AddrIndex)
{
// Wait if RTC internal "Update in Progress"...
while (ReadRTC (RTC_RegisterA) & 0x80);
// Read RTC Time Byte in Bin or BCD format, return always Bin...
if (ReadRTC (RTC_RegisterB) & 0x02)
return ((ReadRTC (AddrIndex) ›› 4) * 10 + (ReadRTC (AddrIndex) & 0x0f)); // BCD -› Bin
else
return (ReadRTC (AddrIndex));
}
//***************************************************************************
void WriteRTC (WORD Addr, BYTE Value)
{
WritePort (RTC_AdrPort, (BYTE) Addr); // Write Addr. to RTC Addr. Port
WritePort (RTC_DataPort, Value); // Write Data to RTC Data Port
}
//***************************************************************************
BYTE ReadRTC (WORD Addr)
{
WritePort (RTC_AdrPort, (BYTE) Addr); // Write Addr. to RTC Addr. Port
return (ReadPort (RTC_DataPort)); // Read RTC Data Port
}
//***************************************************************************
void main (void)
{
int nGdriver, nGmode, nColor;
char szBuffer[16];
// Setup GraphicsMode...
detectgraph (&nGdriver, &nGmode);
initgraph (&nGdriver, &nGmode, "..\\bgi");
nColor= getcolor ();
setfillstyle (EMPTY_FILL, nColor);
settextstyle (DEFAULT_FONT, HORIZ_DIR, 8);
setviewport (0, 0, 639, 479, 0);
// Set new InterruptHandler for IRQ8 (RTC Interrupt)...
oldIRQ8Handler= getvect (0x70);
SetIRQ (IRQ8, IRQ8Handler);
// Enable RTC Interrupt...
WriteRTC (RTC_RegisterB, (BYTE) ((ReadRTC (RTC_RegisterB) | 0x40) & 0x7f));
EnableIRQ (IRQ8);
// Update RTC Time and Interrupt Counter on Screen...
while (bioskey (1) == 0) {
// Update RTC Time in upper half...
clearviewport ();
sprintf (szBuffer, "%02d:%02d:%02d",
ReadTimeByte (RTC_Hours),
ReadTimeByte (RTC_Minutes),
ReadTimeByte (RTC_Seconds));
outtextxy (65, 95, szBuffer);
// Update Interrupt Counter in lower half...
if (glIrq8Counter › 999999l) glIrq8Counter= 0;
sprintf (szBuffer, "%06ld", glIrq8Counter);
outtextxy (130, 325, szBuffer);
// Line upper/lower half. Delay for next Update...
line (0, 240, 640, 240);
delay (1000);
}
// Disable RTC Interrupt, Reset IRQ8 Vector...
DisableIRQ (IRQ8);
WriteRTC (RTC_RegisterB, (BYTE) (ReadRTC (RTC_RegisterB) & 0xbf));
SetIRQ (IRQ8, oldIRQ8Handler);
bioskey (0);
closegraph ();
}