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Is DSP/BIOS Overkill for a Control Project?

Other Parts Discussed in Thread: TMS320F28335, TMS320C28346

This question is open to TI employees and customers. I am interested in both perspectives.

I am developing a power electronics controller that must support a lot of features.  I started the project with a TMS320F28335 and had gotten to a point where all the peripheral devices woked in CCS3 with DSP/BIOS (internal ADCs synchronized with the ePWMs). The DSP/BIOS debugging/scheduling features was what originally attracted me to the framework.  Do practicing digital control engineers ever use the BIOS? The framework seems targeted to video/audio applications and not control. All TI's MCU examples are written without a BIOS and it was very painful to translate the non-BIOS code to BIOS supported code.

I put the project on hold for a few months since CCS4 was about to come out. The major overhaul ( the largest IDE change in TI history?) seemed to warrant the wait. Also, I switched to a TMS320C28346 with external ADCs, since I ran out of them on the TMS320F28335. So now I am back at ground zero--new processor, new IDE, and now a new BIOS (v6). 

I understand CCS4 is new, but I have already hit some pretty nasty errors trying to create a CCS4 RTSC project for the TMS320C28346. This has caused me to question if the debugging/scheduling features in the BIOS justify the added headaches and performance hits.

So here is the open question:
Do you use DSP/BIOS in your Control Projects? If so, in what ways has it helped you?

Thanks for the input.
Grant

  • Grant,

    Good question.  In my opinion BIOS is still a great fit for a control application assuming that you have "other stuff" besides your main control loop.  For your time sensitive control loop I recommend working "outside BIOS" by not using the dispatcher (i.e. reduced latency) and getting your time critical processing done ASAP.  For everything else, BIOS is awesome.  The concept of tasks gives you tremendous flexibility in terms of scheduling.  Plus you have all the other goodies like instrumentation, semaphores, etc.

    It's not clear to my why you're changing to CCS4 and BIOS6.  As far as BIOS6 goes, it's a total re-write of BIOS and has some nice new stuff in it.  Personally I think it's still too hard to use and for the time being I recommend that you stay with BIOS5.  In my mind, BIOS5 is the gold standard of TI software.  It's well documented, has clear examples, and is bullet proof.  As far as IDE, that's another one where you could stay with CCS 3.3 or move to CCS 4.0.  Personally I really like CCS 4.0 and I don't plan on going back to 3.3.  It's a lot different though and requires a bit of time to get used to it.

    Brad