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Selection of an appropriate DSP processor

gaurav pant
Prodigy 50 points
Other Parts Discussed in Thread: TMS320F28335

Hi, i am a Student of Electrical engineering and i m working on a project which involves harmonic analysis of current (50 Hz fundamental). Can anyone suggest me a cheap DSP processor for this purpose.

  • 0
    TI__Guru*** 125430 points

    Does the board need to interface to something?  How will you get data in and out of the board?  Or is this more of a simulation where you'll just define a test vector in memory and then process it?

  • 0 in reply to Brad Griffis
    Prodigy 50 points

    we will be giving the inputs directly to ADC (in built ADC in the chip) via current sensor.

  • 0 in reply to gaurav pant
    TI__Guru*** 125430 points

    How many bits of resolution do you want/need in the ADC?  What's the voltage range of the signal you're measuring?  At what speed do you want/need to sample?

    There's also question about what other peripherals you might need: USB, UART, SPI, I2C, etc.

    How much memory do you need?  Do you need to do floating point arithmetic or fixed point arithmetic?  Any guess of how many MIPS/MHz?  Do you have a cost target?

    These are the things that need to be known in order to choose the right processor.  Otherwise you'll likely end up with a processor that doesn't get the job done.

  • 0 in reply to Brad Griffis
    Prodigy 50 points

    10 to 12 bits will be sufficient, the out put of the current sensor will be 5V (max), as i m working with 50 Hz fundamental so any reasonable sampling frequency will be okay.

    at least one UART must be there as i am continuously displaying the harmonics (average of the samples within 0.5 second or so).

    i need to implement FFT code on the input waveform using Fixed Point (Q number format), i don't know how much memory i will need. can you help me out here.

    and thank you very much for your replies.

  • 0 in reply to gaurav pant
    TI__Guru*** 125430 points

    I think something like our F28335 eZdsp would be a good fit:

    http://www.ti.com/tool/tmdsez28335

    Our c2000 family of processors is geared toward things like motor control, digital power supplies, etc.  There are libraries available for fixed FFTs and various control algorithms.

    If you have follow-on questions related to this processor please start a new post in the c2000 forum.  Please click "verify answer" on this post if this looks like a good fit for your application.

    Best regards,
    Brad

  • 0 in reply to Brad Griffis
    Prodigy 50 points

    hey brad, that's great help

    thank you so much for your responses. i read the datasheet and it is quite good for our purposes. i want to buy this processor (only processor, not the whole target board), so how can i buy it and how much it will cost? also how do i program it. is there a specific programmer?

     

    gaurav

  • 0 in reply to gaurav pant
    TI__Guru*** 125430 points

    This info can be found in the product folder here:

    http://www.ti.com/product/tms320f28335#pricingpackaging

    Just click the "Sample or Buy" button.  Make sure you choose the appropriate package.  It looks like there's inventory available at multiple distributors.

    Brad

  • 0 in reply to Brad Griffis
    Prodigy 10 points

    Hello TI,

        I have a question regarding TMS320F28335. 

    Context: Connecting 256kX16 SRAM to TMS320F28335.

    Problem: There are two external write enable pins in TMS320F28335, XWE0 (pin137) and XWE1 (pin 151). I am confused in connecting them to an external SRAM as there is only one write enable pin in the SRAM. 

    Looking forward to your positive reply..