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Design >> Mixed-Signal Design >> Questions about SPI interface.
https://designers-guide.org/forum/YaBB.pl?num=1328133385

Message started by xuedashun on Feb 1^st, 2012, 1:56pm

Title: Questions about SPI interface.
Post by xuedashun on Feb 1^st, 2012, 1:56pm

I am going to design a project which uses SPI interface, which has 4 signals: SS* SCLK MISO MOSI. To my knowledge,
SS*, SCLK and MOSI are input singal and MISO is output signals. I have two questions:

1)
I am told the SPI is 25MHz. Is 25MHz too high for this SPI interface? What's the normal frequency range for SPI.

2)
In order to generate the digital output signal (MISO), I need clock signal. Is it possible to directly use SCLK to generate
this digital output signal (MISO)

Thank you!

Title: Re: Questions about SPI interface.
Post by ywguo on Feb 1^st, 2012, 3:24pm

You must have the spec. And the timing diagram is already defined in that spec. Then it is not difficult.

If your chips work fine with 25MHz SCLK, it is OK.

Sure MISO signal can be clocked out by SCLK.

--Yawei

Title: Re: Questions about SPI interface.
Post by PW on Feb 26^th, 2012, 11:47am

You should use sclk as clock reference in transmition and reception.