Wireless motor monitor reference design details

Hi Leonardo,

Thanks for the reply and the design! It’s quite neat. I think I should be alright without the tech basic code now, i’ve nearly finished building a script that graphs the output but i’m sure it will be useful for others. I actually used “pythonista” which is a python ide for iOS which has bluetooth support. I’d highly recommend it if anyone is looking for a tech basic alternative.

I just have one last question, i’m having a problem where the device will crash once I subscribe for updates on 0xFFF5, after writing the appropriate command to 0xFFF1. I haven’t modified the code at all. At the moment i’m trying to modify the ble peripheral code to update slower but not sure if this is the cause of the problem.

Thanks!

Ok, I think i get it now, you can't use updates because you're writing bytes one at a time to 0xFFF5. So basically you just keep reading 0xFFF5 until you've got one new set of data? I think I might modify the program to update on another register when there's a new set of data, then my client will get notified of that can can check 0xFFF5. I guess I could also buffer the incoming data and only write it to 0xFFF5 once. 

Is there anything useful in the other code that's commented out of the SimpleBLEPeriferial? 

Also, is this the actual FFT algorithm?

for(k=0; k<numSamples/2; k++){

zArrayFFT[k] = abs(zArray[j]*zArray[j])/256;

zArrayFFT[k] += abs(zArray[j+1]*zArray[j+1])/256;

j+=2;

}   }

Any progress on this? We're (my company) are currently waiting on it to get the device working.

Hey Leo,

Any update on this? I cant seem to find any 4k fft code that will fit on the microcontroller. To be honest i've been pretty annoyed and frustrated by the lack of detail in this project. Seems more of a show piece than a reference design. I won't be using any other TI reference designs and probably parts in the future. 

Hi John,

I apologize for not getting back to you sooner.  The FFT code should be released within a few weeks.  I'll be happy to help you with it as soon as it's been released.

BR,
Leo

Hi Leo,

How's this going? Any idea when the library might be released?

You could use the FIX_FFT code that I have seen around if for some reason that library doesn't get produced in your timeline.

Is one reference of it in action within TI there are many flavors of it out there.

Here is another more recent use of this library since it is open for public use.

Below is some C code I made that will also produce a table for you to use inside this fix_fft.c (This is tested some so keep in mind that it might need a tweek or too) 

You would just run the c code in an online IDE and the output can be copied and pasted into fix_fft.c 

#include <stdio.h>
#include <math.h>
#define POINTS 128
#define BITS   16




int main(void)
{
  int n;
  int a=0;
  int TF_FLAG=POINTS-POINTS/4;
printf("#define N_WAVE      %d    /* full length of Sinewave[] */\n",POINTS);
printf("#define LOG2_N_WAVE %d      /* log2(N_WAVE) */\n",(long)log2(POINTS));
printf("/* 3/4 of N_WAVE = %d  */\n",TF_FLAG);
printf("const int8_t Sinewave[N_WAVE-N_WAVE/4] = {\n");
  for (n=0; n<POINTS; n++){
        if(n==TF_FLAG){
          printf("/*");
        }




  if(a<15){
    printf("%d,", (int)floor(0.5 + ((1 << (BITS-1)) - 0.50001) * sin(2 * 3.1415926535897932 / POINTS * n)));
        a++;}
       else{
        a=0;
        printf("%d,\n", (int)floor(0.5 + ((1 << (BITS-1)) - 0.50001) * sin(2 * 3.1415926535897932 / POINTS * n)));
        }
}
printf("*/");
printf("};\n");




  return 0;
}

Hope that helps or gets you started :-)

Hi John,

The library has just been released! You can download it from:

http://msp430.sc.ti.com/msp430_releases/DSPLib/1_10_00_10/

BR,
Leo

Thanks very much for this Leonardo! Unfortunately I get a DNS error when I try to download the files. Maybe it's just taking a while to update?

msp_cmplx_fft_fixed_q15(const msp_cmplx_fft_q15_params *params, int16_t *src) Is the function I would study as this will pass the source and the params list (I think which is a struct....)