They are capable of doing 2 data moves, a 16x16 multiply, a 40 bit accumulate and a prefech of the next instruction all in 100ns.
This is where a DSP really shines, since it's the fundamental operation in digital filtering; indeed it wouldn't be a DSP if it couldn't do a multiply/accumulate in a single clock cycle. But I wouldn't be too surprised if general purpose CPUs eventually get the same capability. And once they are, the distinction between a "DSP" and a "general purpose" CPU will pretty much vanish. DSPs are notoriously harder to program than general purpose CPUs, and being lower volume items they won't be able to compete in price or clock speed with general purpose CPUs made in the millions. But that's in the future. There's not much alternative to using a DSP chip right now if you want high quality low bit rate speech, but unfortunately the low-cost DSPs now appearing on PC sound cards are not quite up to the task yet. I think CELP encoding requires something like 30 million multiplies per second, which is beyond the reach of a 12.5 Mhz AD2105. On the other hand, simpler schemes and/or clever coding tricks might make it possible. And since these boards are now widely available in computer stores, they're hard to ignore in a project like this. Has anybody looked at them in detail? Phil