timer.c

来自「WinCE 3.0 BSP, 包含Inter SA1110, Intel_815」· C语言 代码 · 共 90 行

/*++
THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT 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.
Copyright (c) 1995, 1996, 1997  Microsoft Corporation

Module Name:

   timer.c

Abstract:

Notes:


--*/

#include <windows.h>
#include <nkintr.h>
#include <alt_def.h>
#include <vrc5074.h>
#include "timer.h"

extern void InitMIPSClock();
extern UINT TimerISR();


void InitClockTimer2()
{
    PVRC5074_CONTROL pVrc5074 = (PVRC5074_CONTROL) (KSEG1_BASE | VRC5074_BASE);

		//RETAILMSG (1, (TEXT("T2CTRL.Lo address = 0x%x\r\n"), &pVrc5074->T2CTRL.Lo));
        //RETAILMSG (1, (TEXT("T2CTRL.Hi address = 0x%x\r\n"), &pVrc5074->T2CTRL.Hi));
        //RETAILMSG (1, (TEXT("T2CNTR.Lo address = 0x%x\r\n"), &pVrc5074->T2CNTR.Lo));
        //RETAILMSG (1, (TEXT("PERIOD_INC = 0x%x\r\n"), PERIOD_INC));
        
        pVrc5074->T2CTRL.Hi = 0x00;                     // Stop the timer.

        pVrc5074->T2CTRL.Lo = PERIOD_INC;       // This gives 1 ms !!!
        pVrc5074->T2CNTR.Lo = PERIOD_INC;       // Start counting from here.

        pVrc5074->T2CTRL.Hi = 0x01;                     // Let's boogie now...

        // Enable timer2 interrupt.
        //RETAILMSG (1, (TEXT("INTCTRL.Lo address = 0x%x\r\n"), pVrc5074->INTCTRL.Lo));
        pVrc5074->INTCTRL.Lo = pVrc5074->INTCTRL.Lo | 0x08000000;
}


void InitClock(void)
{
//    HookInterrupt(4, (void *)TimerISR);
//    InitMIPSClock();
}


int GetTimerPeriod(void)
{
   return(CPURTCSHORT_PERIOD);
}



// Return a better than 25 ms resolution...
DWORD SC_GetTickCount(void)
{	
	PVRC5074_CONTROL	pVrc5074 = (PVRC5074_CONTROL) (KSEG1_BASE | VRC5074_BASE);	
    DWORD				dwBaseMs, dwCurCount, dwTickCount;

    do
    {
        dwBaseMs = *(volatile unsigned long *)AddrCurMSec;		
		dwCurCount = pVrc5074->T2CNTR.Lo;		
    }
    while ((dwBaseMs != *(volatile unsigned long *)AddrCurMSec));

 	// Not forgeting that counter counts down.
	dwCurCount = PERIOD_INC - dwCurCount;
	
	//  Up to date mSecond = *AddrCurMSec + dwCurCount adjusted to ms unit.	
	dwTickCount = dwBaseMs + (dwCurCount * CPURTCSHORT_PERIOD) / PERIOD_INC;

	return dwTickCount;
}