On Thursday, June 04, 1998 0:19, Kevin Timmerman[SMTP:opossum@EGL.NET]
wrote:
> >         My problem is that, i want to have fixed clocks,
> > independent of machine, to talk with
> > DS1307. I have done a "delay" routine with "FOR" command, but
> > i think that's not correct!
> >
> >         Can someone say me how i do short 'delays' in
> > WINDOWS? (500us) for example!
> >
>
> The GetTickCount() kernal function provides 1ms resolution on Windows
> 95/98/NT.
>
> From the Visual C++ docs....
>
> The GetTickCount function retrieves the number of milliseconds that have
> elapsed since Windows was started.
>
> DWORD GetTickCount(VOID)
>
> Parameters
> This function has no parameters.
>
> Return Value
> If the function succeeds, the return value is the number of milliseconds
> that have elapsed since Windows was started.
>
> Remarks
> The internal timer wraps around to zero if Windows is run continuously for
> approximately 49.7 days.
> The GetTickCount function is identical to the GetCurrentTime function.
> Applications should use the GetTickCount function because its name matches
> more closely what the function does.

GetTickCount() granularity is 18ms although the result comes in ms. The
fuctions to use is QueryPerformanceFrequency and
QueryPerformanceCounter. With this two you get a resolution of
micro-seconds or better. They work in win95 and winnt.
Try this C code:

LARGE_INTEGER freq, antes, depois;
BOOL rr = QueryPerformanceFrequency(&freq);
QueryPerformanceCounter(&antes);
/* elapsed time */
QueryPerformanceCounter(&depois);
printf("tempo %g\n",
((double)(depois.QuadPart-antes.QuadPart))/freq.QuadPart);


Best Regards,
Paulo Soares
psoares@consiste.pt