wince下RTC驱动该如何写？芯片是M41T81

Question

我的板子核心CPU是PXA270，然后我有一个外接的RTC芯片M41T81，用它来实现实时时钟，可是现在关机后，每次重启时间都会归零。
我的IIC总线有两个IC器件在用，一个是摄像头，一个就是这个M41T81。我把我的RTC驱动部分代码贴出来，请大家指教。
BOOL
OEMGetRealTime(LPSYSTEMTIME lpst)
{
unsigned int cur_time;
// Get the RTC value
GetRTCTime (&cur_time);
FormatSystemTime (cur_time, lpst);

//QU_GetRTCTime (lpst);

#if 0
DEBUGMSG(0,(TEXT("OEMGetRealTime: Year: %u, Month: %u, Day: %u, Hour: %u, Minute: %u, second: %u rcnr=%Xh\n"),
lpst->wYear, lpst->wMonth,lpst->wDay, lpst->wHour, lpst->wMinute,lpst->wSecond, cur_time));
#endif

return TRUE;

}

//
//
// Sets the RTC.
// Called by kernel in response to SetSystemTime()
//
//
BOOL OEMSetRealTime(LPSYSTEMTIME lpst)
{
unsigned int cur_time;
ConvertSystemTime (lpst, &cur_time);
SetRTCTime (cur_time);
//QU_SetRTCTime (lpst);

#if 0
DEBUGMSG(0,(TEXT("OEMSetRealTime: Year: %u, Month: %u, Day: %u, Hour: %u, Minute: %u, second: %u rcnr=%Xh\n"),
lpst->wYear, lpst->wMonth,lpst->wDay, lpst->wHour, lpst->wMinute, lpst->wSecond, cur_time));
#endif

return TRUE;

}

//
//
// Set the RTC alarm.
// Ensure synchronization to RTC registers.
//
// Default behavior will allow setting an alarm
// (thereby cancelling any pending one)
//
//
BOOL OEMSetAlarmTime(LPSYSTEMTIME lpst)
{
unsigned int min, day, month, year;
unsigned int *mtbl;
unsigned int alarm_time;

XLLP_RTC_HANDLE_T   XllpRTCHandle;

XllpRTCHandle.pRTCRegs = (XLLP_RTC_T *)RTC_BASE_U_VIRTUAL;
XllpRTCHandle.pINTCRegs = (XLLP_INTC_T *)INTC_BASE_U_VIRTUAL;

day = 0;
for (year=ORIGINYEAR; year<lpst->wYear; year++) {
    day += 365 + isleap(year);
}

mtbl = isleap(year) ? monthtable_leap : monthtable;
for (month=0; month<((unsigned)lpst->wMonth-1); month++) {
    day += mtbl[month];
}

day += lpst->wDay - 1;

min = (day * 24 + lpst->wHour) * 60 + lpst->wMinute;

alarm_time = min * 60 + lpst->wSecond;

// 
// Configure and arm the alarm 
//
XllpRtcConfigureAlarm (&XllpRTCHandle, alarm_time);


return TRUE;

}