K66 SPI MISO Decay

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K66 SPI MISO Decay

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lfost
Contributor I

Working with a k66 micro.  Noticed the spi miso line ends high then drifts low.  The k64 does not do this.  No software affects it.  A pull up resistor fixes the decay/drift but is typically not done.  Is this normal for a k66?

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myke_predko
Senior Contributor III

@lfost 

If you're not using one of the SPI pin functions, you don't need to assign a pin to the function.  

That's the easiest solution (with the next easiest one putting a pull up on it or tying the pin to GND the way you have) otherwise you'll probably see delays and other weirdness.  

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nxf77486
NXP Employee
NXP Employee

Hello @lfost ,

 

Some followers leaves the line floating when he is not handling it. In these cases the recommendation is to configure a pull-up in the MISO line so that it does not float when the follower so not driving the line.

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