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sequential and combinational logic in VHDL

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Alles Gute

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vhdl combinational logic

In a VHDL code , we MUST separate the sequential and combinational logic, otherwise the code will obsolutely be unsynthesizable.
Is this correct?
 

combinational logic vhdl

You can mixed combinational (AND OR NOT...) and sequential ( CLOCK process ) in VHDL code.
 

combinational vs sequential process vhdl

Wrong!
Its a good coding practice to separate the sequential and combinational logic; But
even if you mix them the code will be synthesizable.
 

vhdl programming - combinational logic

ive uploaded some ppts reg seq and combinations ckts.
 

vhdl model of combinational logic forums

I guess it is a better coding practice to Have sewuential logic and Combinational logoc separate. Some experienced coder doesnt like the idea as their code becomes more redable try to club them together appropriately
 

model combinational sequential separately

You can easy mix them together. Sometime, the structure of your program will become more clear with mixed type of definition. Also, it will be more easy for synthesizer to optimize your code. For example, if you want to define simple adder with latch on output, I think this construction:
Code:
PROCESS(clk)
BEGIN
   IF (clk'EVENT AND clk='1') THEN
      C_latch<=A+B;
   END IF;
END PROCESS;
will look much better than this:
Code:
PROCESS(A,B)
BEGIN
   C<=A+B;
END IF;

PROCESS(clk)
BEGIN
   IF (clk'EVENT AND clk='1') THEN
      C_latch<=C;
   END IF;
END PROCESS;
 

good coding practices vhdl

Separating sequential from compinational logic ease the synthesis process, and make it easyer to track and debug your code.

using either technique, your design will be synthesisable.
 

vhdl +ppts

i don't agree with you Gute...
one can have combinational circuit...and sequential circuits.....
but it all depends on the design requirements....combination of combinational logic and sequential logic is SYNTHESIZABLE.....
 

advantage of sequential logic in vhdl

No.. That isnt the case....
 

vhdl code sequential & combinational processes

yes i do agree with nand gates .when u synthesize your code u should be able to ciscern whether u have got the correct results or not by an inspection.so if u seperate your code and use good coding practices like not using variables in clocked processes and also code so that unnecessary muxes are not inferred ur design should be prefectly synthesizable.

regards
amarnath
 

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