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How portable is the arc detection library?

Other Parts Discussed in Thread: TMS320F2812, TMS320F28033, TMS320F2808, TMS320F28335, TMS320F28064

How easily can the arc detection library be ported to a different C2000?  The SM73201-ARC-EV with a TMS320F28033 uses the Arc Detection library (C28x_ArcDetect_Lib.lib).  What work would be involved to use this library on a TMS320F2808 and on a TMS320F2812?  The other option is to force the customer to abandon the TMS320F2808 and TMS320F2812 in favour of the TMS320F28033.  What do you suggest?

  • Hi Jason,

    The major consideration is RAM space. Ive provided a space(RAM+FLASH) requirement breakdown for the arc detect library as it stands today. You will need about 6Kwords of RAM space(mainly for the FFT buffer and self-test vectors). The demo code that ships with the RD-195 board runs to about 8K of RAM space; the demo code has the application wrapper that goes around the arc detect library and it also integrates the IEC60730 safety library.

    It looks like the 2808, 2812 have about 18Kwords of RAM so it should fit and they are fast enough.

    Section                        Object File             Memory(hex) Memory(words)
    Code(.text)                   ArcDetect.obj            0x45a         1114
                                         FFT32_calc.obj        0x108         264
                                         CFFT32_brev.obj     0x020         32
                                         FFT32_izero.obj       0x00e         14
    RAM Functions            ad_acquire_data.obj 0x1c            28
    (ramfuncs)             
    Initialized Vars              ArcDetect.obj            0x038          56  
    (.cinit)               
    Test Vector                   ArcDetect.obj            0x800          2048
    (ArcTest)              
    Constants                    ArcDetect.obj
    (.econst)                       Hanning Window)    0x800          2048    
    Uninitialized Vars          ArcDetect.obj           0x120          288
    (.ebss)                
    FFT Buffers(FFTipcb)   ArcDetect.obj          0x1000        4096
    Twiddle Factors(FFTtf) ArcDetect.obj          0x600          1536
    Total                                                             0x2D04      11524

  • The speed and memory specifications of the F2812, F2808 and F28335 that the customer has been using are superior to the F28033.

    C2000   Device (US$)   @ 1 kU Series Flash(KB) RAM(KB) Frequency(MHz)
    TMS320F28335 $14.25 Delfino 512 68 150
    TMS320F2812 $14.25 C28x Fixed-point 256 36 150
    TMS320F2808 $11.05 C28x Fixed-point 128 36 100
    TMS320F28033 $4.60 Piccolo 64 20 60

    Aside from the performance specifications, are there any other restrictions we place as Texas Instruments about what C2000 device the arc detection library can be used on?  The Application Report, "AN-2154 RD-195 DC Arc Detection Evaluation Board," mentions that the filtering technique is proprietary.  What restrictions does this impose?

  • Vishal_Coelho said:

    FFT32_calc.obj

    On a separate note, how did Texas Instruments decide on using the TMS320F28033?  Was this purely based on the lowest cost part that can get the job done?  If you're doing a 32-bit FFT, why not use the TMS320F28064 which has a floating point unit and the Viterbi, Complex Math and CRC unit (VCU I)?

    C2000 FFT: VCU, FPU or FixedPoint

  • Jason

    with regards to the software, there is no restriction on which C2000 device the customer can use.  The F28033 was choosen originally due to being in the RSH package, which was attractive due to the small size for the eval board. As Vishal mentioned, as long as the code fits, it can migrate from device to device.

    You can email me direct about the licensing agreement. It's all free, we just need some customer signatures, nothing complicated.

    Brett N