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MSP430F155: MSP430

robin gangopadhya18
Mastermind 6050 points
Part Number: MSP430F155
Other Parts Discussed in Thread: MSP430FR2355

I need to implement high order Bessel filter with least delay and phase shift of the input signal. Output has to be filtered version of the input. Input is 50Khz samples of 420 Hz signal. Essentially the idea is to recover the 420 Hz tone from the samples without any substantial phase shift.So if the cut-off freq of a 10th order Bessel is approx 5 Khz, I suspect phase shift on 420 Hz will be < deg or so. You would  think so?

Output also has to be "real time" meaning least delay.

Can this be implemented by using WDSP filter design techniques?

Then I need a DAC in the MCU.

I only find MSP430F155IPM, an LPQF 64 leadless device.

Isn't there a smaller device with DAC & with gull wing pins? As  you see, I do not strictly need an ADC.

This will go in a miniature product with lots of such capabilities. So a small device will suffice.

Any help in selecting the right device will be appreciated.

  • 0
    Guru 88580 points
    The msp430fr2355 has 4x DACs, and comes in an LQFP (quad leaded) and even a TSSOP. 24MHz, but no DMA.

    Analyzing samples at 50kHz might be a challenge. The FR2355 has some DSP function in ROM, but I haven't tried it.
  • 0 in reply to Bruce McKenney47378
    Mastermind 6050 points

    thnx Bruce.

    So what is the max easy to implement sampled signal one can send?

    bear in mind the original signal is a single tone signal.

    It is being chopped at 50 Khz but can be lower.

    Pulse duty is typ 50%

    All we need is to reproduce that signal in a manner with least phase shift between original & the filtered version.

    It is interesting to note that I can use Active filtering using opamps but will require at least 2 quads with mucho R &C- area taken up by them is MORE THAN a small MSP430 or similar.

    I  can also use some other chip but we are TI MCU based house- so prefer keeping one vendor for all embedded code based designs.

    Appreciate some other MSP or tiny DSP that can do the job.

    -robin

  • 0 in reply to robin gangopadhya18
    Guru 88580 points
    The "might be a challenge" was just a generic observation. There are certainly some things you can do at 50ksps, but 480 clocks/sample can go pretty quickly. I'm not familiar with WDSP, but I imagine those who are have some notion of its complexity.

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