AnsweredAssumed Answered

FRDM-KL05Z SPI problem?

Question asked by gary shi on Nov 28, 2013
Latest reply on Feb 17, 2016 by Carlos Hass

Hi all,

I used SPI to read a 12-bits device. Thus, the SPI read 2 bytes to finish the read.

However, something strange is, if I set the SPI clock rate faster than 0.333525us, then the "chip select" will still toggle even I set it as no.

It cause a wrong reading if CS was toggled between characters transmission.

SM1_clock.jpg

Below waveform shown the result when set the clock rate to 0.333525us.

The SPI read 2 bytes data continually without CS toggling.

tek00005.png

Below waveform shown the result when set the clock rate to 0.083381us.

The CS will be toggling between characters transmission.

tek00006.png

 

Hope someone can help one this.

 

Thanks.

Gary.

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