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attila

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Posts posted by attila

    Digital Discovery to collect 16 bit SPI data - multiple slaves with same CS, CLK, MOSI and individual MISO

    in Test and Measurement

    Posted

    Hi @Shalin

    Try lower IO voltage. Eventual pullup which can help if the driver has some impedance.
    The absolute minimum is around 0.96V but even if you try lower value it will limit to what it can. (The minimum recommended for the FPGA IO supply is 1.1V)

    Here with 0.95V the threshold is 0.55V/0.65V
    AD3 Wavegen is connected to one DIO of Digital Discovery and another DIO outputs the logic level of the input (with ROM Logic) which is connected to AD3 Scope 1.

    image.png

    image.png

    Graphing wave frequency as custom channel (?) in WavForms

    in Test and Measurement

    Posted

    Hi @Agouti

    With Math channel the data can only be delayed. For compensation bidirectional shifting is available under Channel gear dropdown.
    However with Logging you can process the data to show the exact length of each pulse.

    image.png 

    if(!Scope.Ref1.enable) Scope.Ref1.Clone(Scope.Channel1);
var src = Scope.Channel1.data;
var c = src.length;
var dt = 1.0/Scope.Time.Rate.real;
var pwm = [];
var p = src[0]>0;
var t = dt, j = 0;
for(var i = 1; i < c; i++, t+=dt){
    if(p==(src[i]>0)) continue;
    p = !p;
    for(; j<i; j++) pwm.push(t);
    t = 0;
}
for(; j<c; j++) pwm.push(t);
Scope.Ref1.setData(pwm, Scope.Time.Rate.real);

     

    Working with the digital discovery board SDKs

    in Test and Measurement

    Posted

    Hi @ssm

    If you specify 32bit samples you get 32bit samples. You are also using 32bit array, uint. How are you looking at the values ?

    Here a 32bit walking 1 signal is connected to Digital Discovery DIN 0 to DIO 31 and captured like this:

    image.png 

    #include <stdio.h>
#include <stdlib.h>

#ifdef WIN32
#include "dwf.h"
#elif __APPLE__
#include "/Library/Frameworks/dwf.framework/Headers/dwf.h"
#else
#include <digilent/waveforms/dwf.h>
#endif

int main(int carg, char** szarg) {
    HDWF hdwf;
    STS sts;
    double hzSys;
    int cSamples = 100000;
    unsigned int* rgdwSamples = new unsigned int[cSamples];
    char szError[512] = { 0 };

    if (!FDwfDeviceOpen(-1, &hdwf)) {
        FDwfGetLastErrorMsg(szError);
        printf("Device open failed\n\t%s", szError);
        return 0;
    }

    FDwfDigitalInInternalClockInfo(hdwf, &hzSys);
    FDwfDigitalInDividerSet(hdwf, (unsigned int)(0.5 + hzSys / 200e3)); // 200kMHz
    FDwfDigitalInSampleFormatSet(hdwf, 32); // 32 bit samples
    FDwfDigitalInBufferSizeSet(hdwf, cSamples);
    FDwfDigitalInConfigure(hdwf, false, true);
    do {
        if (!FDwfDigitalInStatus(hdwf, true, &sts)) return 0;
    } while (sts != stsDone);
    FDwfDigitalInStatusData(hdwf, rgdwSamples, cSamples * sizeof(unsigned int));
    for (int i = 0; i < cSamples && i < 30; i++)  printf("0x%08X\n", rgdwSamples[i]);
    FDwfDeviceCloseAll();
}

     

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