[coreboot] Memory clock cycles -> microseconds (us)
peter at stuge.se
Mon Jun 9 19:14:32 CEST 2008
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
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