Re: [LAD] Is RME HDSPe AES supported by alsa?

Niels,

> IIRC, they put such a huge matrix on it because they designed one
> chip to slap on all their cards in that family. Saves money to just
> design and fab one chip instead of a separate chip for each unit.
> RME uses FPGA's, which is why they're so expensive

The Spartan 3 doesn't cost that much. What's in the firmware is what
makes them expensive.

> ( http://www.rme-audio.de/en_support_techinfo.php?page=content/support/en_support_techinfo_hdsp_totalmix_hardware ).
> It's several bazillion of
> these http://en.wikipedia.org/wiki/File:FPGA_cell_example.png that you
> can connect up into any electronic circuit you want.

Not really. And it's only a few thousand.

> I'd imagine they
> designed it so that each FPGA takes a certain number of channels and
> there's an addressing limit to how many FPGA's can be chained together
> in a multi-channel rig... thus the 64 channels of inputs even though
> each card has only 16 ins.

Well, there are constraints, like the number of dedicated multipliers,
you have almost no storage capabilities and so on. But if you think of
the 8192 mixers for example a MADI card has to calculate for each sample
period, you can use a divide and conquer strategy to add up the data and
be done with it in a matter of a few cycles. After all, 64 is a nice
two's complement :)

Flo

-- 
Machines can do the work, so people have time to think.
public key DA43FEF4          x-hkp://wwwkeys.eu.pgp.net
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