I am having some problems about using the FIR Compiler multi-column support in Spartan3400A.
I downloaded the Spartan3 and FIR Compiler user guides, but both aren't enough specific on how to configure the following:
First Column Length
Column Wrap Length
Ok, here's my problem:
I want to design a FIR filter with hardware-over-sampling rate of 4. And I want to use the 3 central columns of spartan3400A DSP. Each central column has 26 DSP48 slices.
When I use this configuration (only one column)
Filter Length= (26-1)*4
Hardware over sampling rate = 4
First Column Length = 26
Column Wrap Length = 26
There's no errors.
But when I try to use the 3 larger columns:
Filter Length= (26*3-1)*4
Column Wrap Length = 26*3
A "standard exception" is raised.
Well, there's some detail about the First Column and Column Wrap lengths that I'm skipping.
I want to find a mathematical equation that gives me the Filter Length from these other 3 inputs:
Hardware over sampling rate (hosr)
First Column Length (fcl)
Column Wrap Length (cwl)
F_length = (cwl-1)*hosr (works) *(1)
If fcl=26 and cwl=26*3 , I'm trying:
F_length = (cwl-1)*hosr (not works)
*(1) The "minus one" saves space for the accumulator.
Thanks everyone, and sorry if this post was too long.