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Configurable case loop in verilog

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pawangupta

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Hi all,

I want to write a configurable verilog code of case statement....please help me, if any idea...

Example_1:
In this simple example, i know how many case expressions may exist in my case loop...4:

parameter COUNT_WIDTH = 4

case (COUNT_WIDTH)
4'b0001: something;
4'b0010: something;
4'b0100: something;
4'b1000: something;
default: something;
endcase

But at latter time, user defined COUNT_WIDTH = 15, how can i write this configurable requirement in verilog HDL so that i need not to modify my RTL when user requirements changes.

CONFIGURABLE CASE LOOP ?????
 

Hi,

I'm not quite sure, whether I understand your question correct or not.

I think you could generate different case statements depending on your parameter

e.g.

Code: 
  generate
    if ( COUNT_WIDTH == 1 )
     begin : GEN_CW_1
        case (counter)
        1'b1: something;
        1'b0: something;
        default: something;
        endcase
     end
    else if ( COUNT_WIDTH == 4 )
     begin : GEN_CW_4
        case (counter)
        4'b0001: something;
        4'b0010: something;
        4'b0100: something;
        4'b1000: something;
        default: something;
        endcase
     end
...
    else if ( COUNT_WIDTH == 15 )
     begin : GEN_CW_15
        case (counter)
        15'h0001: something;
        15'h0002: something;
        15'h0003: something;
        15'h0004: something;
        ...
        15'h7fff: something;
        default: something;
        endcase
     end
    else
     begin : GEN_DEFAULT
     end
  endgenerate

or you could extend to your maximum case with and do something like this

Code: 
parameter COUNT_WIDTH = 4

reg [COUNT_WIDTH-1:0] counter;

wire [15:0] extended_counter;

assign extended_counter = {{(16-COUNT_WIDTH){1'b0}},counter}

case (extended_counter)
16'h0001: something;
16'h0002: something;
16'h0003: something;
16'h0004: something;
...
16'hffff: something;
default: something;
endcase

regards
 

the first solution pointed out by qieda works. yet, i really couldnt understand what you were actually trying to do. please ttry to explain better what u are trying to do, perhaps a better solution exists.
 

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