Honored Contributor
Honored ContributorAlthough this thread is stale by almost a year, I was wondering if anyone has had any luck (good or bad) with the coefficient reloading. I am currently working on a design that requires an 11-tap FIR filter that's re-loadable using the coef_in and coef_we ports. I have tried using the coef_seq program, and my 11 coefficients turn into 64 when I run the script, and I'm wondering why this is the case. I'm basically taking 11 values (already scaled) and running the following:
>coef_seq coef.txt coef_mod.txt PAR M512 MSYM 18 1 SGL 1 18 At least, in the example that Altera provides (using a 40-tap filter), the number doubled, which still isn't real intuitive, but at least it's not more than 4x. http://www.altera.com/support/examples/verilog/ver-fir-coefficient.html I was hoping to use this example, but my flavor of Modelsim AE is VHDL-only, so I couldn't get a good look at how the timing of the coef_in and coef_we signals was looking, because it's Verilog-based. The FIR Compiler datasheet gives a good enough description, but doesn't provide much insight to where to place, for example, a scaled 18-bit coefficient into a data bus that's 21-bits wide (which is another question that I've got). My most recent stab at simulating this has me instantiating my coefficient reload VHDL module into a DSP Builder .mdl and then trying to view the results of the coefficient reload "real time" in Simulink, but it's not exactly working as I had hoped. I also tried bringing the FIR filter in Modelsim, but I had too difficult of a time getting all of the proper libraries loaded (each time I found one that was missing, it called another library that either wasn't there or encrypted). Anyways, I don't have a really specific question, other than wondering if anyone's got this figured out. Jeff
