Em 26/6/2010 15:42, Harold Hallikainen escreveu:
>> Harold Hallikainen wrote:
>>> The 75MHz speed is what the SPI flash is rated at. I'm running a LOT
>>> slower than that. But, the fact that the flash can respond to 75MHz
>>> clocks makes it real sensitive to very short reflections on the line
>>> that other chips do not respond to.
>> OK, but it's still useful to know the top speed the clock will actually =
be
>> run at.  That determines how much you can filter the clock output and
>> therefore avoid frequencies that are susceptible to reflections and the
>> like.
> Because I'm using 16 bit PMP on the part, all the SPI ports are not
> available. I'm bit banging at about 2MHz.
>
> Harold


At such low speed you can use a higher value for the series resistor,
lowering the slew-rate to a point where the transmission-line effects
disappear.

Isaac

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