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creating a matrix of instances in verilog-A

rickrevolta

Hello

I am trying to create a matrix of instances but not successfully so far. It is composed by 120 rows and 160 columns. I have to separate it in row/column even and odd. So I have 60 even and odd rows and 80 even and odd columns. I am trying to use  two for construction to instantiate the devices  between the rows and columns but I am facing some difficulties. I have to name the instances, and I tried to do it using a variable but does not work. It thinks that i am trying to use a function. The instance is a photodiode and I am nameing them by d_odd and d_even. Could you help me on that ? thanks

 

`include "constants.vams"
`include "disciplines.vams"
`include "photodiode.va"
module fpa_120_160(col_even, col_odd, row_even, row_odd);

inout [1:80] col_even;
electrical [1:80] col_even;
inout [1:80] col_odd;
electrical [1:80] col_odd;
inout [1:60] row_even;
electrical [1:60] row_even;
inout [1:60] row_odd;
electrical [1:60] row_odd;

genvar a,b;
integer c,d,k;

real i ;

analog begin
    
    @(initial_step)     begin
        
                                       k = 0;
                                       c = 1;
                                       d = 1;
                              end            
    
    for (a = 1 ; a <= 60 ; a = a + 1 )
        
        i = 0 + 1.666*k;
        
        begin
        
            for (b = 1 ; b <= 80 ; b = b + 1 )
            
                d_odd(c) (col_odd[b] row_odd[a]) photodiode intensity = i;

                c = c + 1;
            
                d_odd(c) (col_even[b] row_odd[a]) photodiode intensity = i;

                c = c + 1;
                
                
                d_even(d) (col_odd[b] row_even[a]) photodiode intensity = i;

                d = d + 1;
            
                d_even(d) (col_even[b] row_even[a]) photodiode intensity = i;
                
                d = d + 1;
        end
                
        k = k + 1;
        
    end        
                
endmodule

  • Andrew Beckett

    You didn't say which simulator you're using. If it's AMS Designer, then this is possible - I added some `DEFINE to make it a little easier to test. The key things wrong were:

    1. You need to put the structural instantiations inside a generate block
    2. You had the syntax of the instantiations wrong
    3. You don't need to make the instances unique over the entire generate - it does that for you
    4. You can't have the assignments inside the for loops like you did - so I did the calculations on the fly on the instance lines

    Note that I don't think this is possible in spectre's VerilogA. The generate statement was the old way of doing genvars in VerilogA - but it has a different meaning than generate in VerilogAMS (I think the new generate comes from Verilog-2001).

    Anyway, here's the code I got to compile. Note I did not test this other than compiling it with "ncvlog -ams". 

    `include "constants.vams"
`include "disciplines.vams"
//`include "photodiode.va"

`define ROWSIZE 60
`define COLSIZE 80

// dummy module because I didn't have it
module photodiode(x,y);
inout x,y;
electrical x,y;

parameter real intensity=1.0;

analog 
  V(x,y) <+ I(x,y)*intensity;
endmodule

module fpa_120_160(col_even, col_odd, row_even, row_odd);

inout [1:`COLSIZE] col_even;
electrical [1:`COLSIZE] col_even;
inout [1:`COLSIZE] col_odd;
electrical [1:`COLSIZE] col_odd;
inout [1:`ROWSIZE] row_even;
electrical [1:`ROWSIZE] row_even;
inout [1:`ROWSIZE] row_odd;
electrical [1:`ROWSIZE] row_odd;

genvar a,b;

generate
    for (a = 1 ; a <= `ROWSIZE ; a = a + 1 ) begin
	for (b = 1 ; b <= `COLSIZE ; b = b + 1 ) begin
                photodiode #(.intensity(1.666*((b-1)*`COLSIZE+(a-1)))) d_odd1(col_odd[b],row_odd[a]);
                photodiode #(.intensity(1.666*((b-1)*`COLSIZE+(a-1)))) d_odd2(col_even[b],row_odd[a]);
                photodiode #(.intensity(1.666*((b-1)*`COLSIZE+(a-1)))) d_even1(col_odd[b],row_even[a]);
                photodiode #(.intensity(1.666*((b-1)*`COLSIZE+(a-1)))) d_even2(col_even[b],row_even[a]);
        end
    end
endgenerate
                
endmodule

    Regards,

    Andrew.

     

  • Andrew Beckett
    Quick reply to see whether email replies are working. Will try to answer the question properly later.

    Regards,

    Andrew.

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