SPI Bus Chip Select - not simply high/ low?

General Electronics
2

In my past experience the ~CS (as it normally is active low) should be the “dumbest” of the 4 SPI pins. If you see a 1 MHz sq wave on there, you probably are either connected to the wrong pin or are coupling in a signal from somewhere else.

I would expect it to look something like this:

image.jpg918×749 144 KB
http://www.byteparadigm.com/pictures/figure2.jpg

However, if you’re not reading the signals properly (even after you figure out that CS stuff), then you might be in the wrong “mode”. This relates to when signals are triggering. See here for more info:

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