Re: [coreboot] Memory clock cycles -> microseconds (us)

[Peter Stuge]

On Mon, Jun 09, 2008 at 01:06:08PM -0400, Joseph Smith wrote:
> > > Does anyone know the mathematical formula for converting memory
> > > clock cycles into microseconds (us)??
> >
> > 1 MHz means 1 million clock cycles per second, so 1 clock cycle
> > per microsecond.
> >
> > 166 MHz -> 166 clock cycles per microsecond.
>
> Thanks Myles:-)
> I didn't realize it was that easy.
> So, for example if a memory initialization datasheet says you
> should delay for 3 clocks than that means 3us, correct?

Only if the memory clock is 1MHz, but if it's 166MHz then delay for
3/166 microseconds = 18 nanoseconds

The formula is: t=1/f

If f=1000000, each cycle is 1/1000000 seconds, or 1 microsecond.
If f=166000000, each cycle is 1/166000000 seconds, or 1/166 us = 6 ns

//Peter