Datapath shift operation: what happens on a left/right shift if the shift output is set to right/left?

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RaAl_264636
Level 6
Level 6
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Hi,

   

 

   

I'm digging deeper into the datapath shift operation. I wonder what happens if a left/right shift operation is executed with the shift input or output set to right/left? Unfortunately I couldn't find explicit information about this special cases in the architecture technical reference manual.

   

 

   

For example, a typical configuration would be Shift = right, Shift in = from left (SIL), Shift out = right (SOR)

   

Now, if Shift out = left (SOL_MSB), the shift output will simply follow the shift input, right?

   

 

   

What happens if Shift out = right (SOR) and Shift in = from right (SIR)? If I understand the shift mechanism right, this combination is not possible, because the shift direction automatically selects the corresponding shift input. Is this true?

   


Regards,

   

 

   

Ralf

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Bob_Marlowe
Level 10
Level 10
First like given 50 questions asked 10 questions asked

-Ralf

   

Did you already have a look into the "DataPath Configuration Tool Cheat Sheet" www.cypress.com/ <- there?

   

Here the selections are explained a little bit (WHAT is a "little" bit? a bit is a bit! Schroedinger, please help me!) better than in other documentations.

   

 

   

Bob

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RaAl_264636
Level 6
Level 6
50 sign-ins 25 sign-ins 10 solutions authored

Hi Bob,

   

 

   

yes, the cheat sheet is is one of the documents which are always open when digging deeper into PSoC 😉

   

 

   

You're right, the bits are described, but the cheat sheet doesn't show the behaviour in detail for a given combination of bits. I'm aware that my above configurations are non-usual and I can't imagine a case where they're useful. I asked just for understanding the internals 😃 And the understanding is growing...

   

 

   

Regards,

   

 

   

Ralf

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