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Design Languages >> Verilog-AMS >> problems with verilog-A generate
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Message started by danmc on May 8^th, 2006, 6:30am

Title: problems with verilog-A generate
Post by danmc on May 8^th, 2006, 6:30am

Hello,

I"m trying to use generate() to produce a bunch of filters. I have an initial block where I use generate to initilialze the gain and banwdith of my filters and then try to do:

generate i (1 , 10) begin
// Transfer function for a first order low pass filter

V(OUT[i]) <+ laplace_nd(in[i], {gain[i]}, {1,tau[i]});
end /

but I get back:
Error found by spectre during SpectreHDL compile.
"/path/to/mycell/veriloga/veriloga.va", line 126: "{1,tau[i]})<<--? ;"
"/path/to/mycell/veriloga/veriloga.va", line 126: Error: arg #2 must be an array variable or a
constant array expression. It cannot be an array expression containing non-constant expressions. If you need
the argument to be variable, use an array variable instead.
"/path/to/mycell/veriloga/veriloga.va", line 126: Error: arg #3 must be an array variable or a
constant array expression. It cannot be an array expression containing non-constant expressions. If you need
the argument to be variable, use an array variable instead.

I want to be able to pass parameters into this model that determine the gain and bandwidth of each filter. However, the gain and bandwidth are functions computed from a different set of user parameters.

Any suggestions?

Thanks
-Dan

Title: Re: problems with verilog-A generate
Post by Geoffrey_Coram on May 16^th, 2006, 7:27am

It sounds like you could set up two array variables, this_gain[0:0] and this_tau[1:0] and assign them values inside the generate loop, ie,
this_gain[0] = gain[i];
this_tau[0] = 1;
this_tau[1] = tau[i];