[sdiy] Some Audio DSP prototypes

Mike Bryant mbryant at futurehorizons.com
Sat Apr 16 11:57:14 CEST 2022

> If supply chain issues are making it difficult to obtain the most popular, general purpose chips - ARM - then it seems like a good time to consider designing with chips that have special purpose instructions sets intended for signal processing. DSP families > like the TMS320 and SHARC will process more audio per Watt than an ARM - even an ARM that has one or two token "DSP" instructions.

> I've designed with the TMS320VC5506, and it has an internal bus that's 80 bits wide, plus DMA and SRAM allowing parallel access of multiple data sets. There are floating point models in the family. They're not as easy to program as a general purpose > CPU, but the effort of learning their special tricks is well worth it.

> A few hundred MHz on a DSP architecture is more than enough to compete with general purpose GHz CPUs, and then you don't have to source expensive ARM-A chips.

> Brian Willoughby

Oddly enough the system I'm designing at the moment is an upgrade to an original design that used a ring of eight TMS320C55s.   But just like most other chips, those are also unavailable in large quantities.   

But anyway A-series chips have full vector processors in them nowadays so they beat any DSP I know of into the weeds.  However of course A series chips are also unobtainium so one has to warp the design to use large numbers of lower end M series processors which seem to be the only MCUs available to mere mortals at the moment.

Raspberry Pi were fortunate in buying up their slots at TSMC just before the crisis hit, and so they have longer term supply stability than many others.  If they were a plc with responsibilities to shareholders, they would probably have sold those slots on to ST or TI at far more profit than they'll ever make out of $1 RP2040s.

More information about the Synth-diy mailing list