You just must be sure that your PCLK is at least 8x the inclock clock in
SCK pin.
jeffbranc01 wrote:
> --- In lpc2000@yahoogroups.com, Sean <embeddedrelated@w...> wrote:
> >
> > Jeff:
> >
> > In the LPC manual (at least for the 2148) it says that the clock speed
> > register is unused when you are operating in slave mode -- the incoming
> > clock signal is used to latch the data.
> >
> > -- Sean
> >
> > At 07:03 PM 1/26/2006, you wrote:
> > >Hello,
> > >This is more of a general question regarding using the SPI peripherals
> > >with the LPC2000 chips. I'm somewhat new to this form of serial
> > >communications, so sorry for boring all you pros out there. I'm
> > >developing with the LPC2220 chip, and am actually using the SSP
> > >peripheral, which, for all intents and purposes works just like an
> > >SPI, but with a few extra options.
> > >
> > >My question is, if you're running the processor's SPI in slave mode,
> > >do you still have to set up your clock speed in the SPI registers to
> > >match the SCLK speed that the external master is giving? Or does the
> > >external SCLK pretty much just clock in everything into the
> > >processor's SPI data registers for you and you don't have to worry
> > >about the SCLK speed (on the processor side)?
> > >
> > >Thanks so much in advance for your help.
> > >Jeff.
> >
> Sean,
> This is good to know because I was going to have conflicting crystal
> speed issues if it did require matching (regardless of clock
> dividers). What you've said is exactly what I had assumed, but I
> looked all over the LPC2220 datasheet and it didn't specify. There
> was one part that barely implied it, but I just wanted to make sure.
> Thanks for the info.
>
>
>
>
>
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