NeedHelpSyncing

So what's the relationship between cSamples/2 and 0? How are they both the "middle of buffer"?

Hi, How would I make sure that the data collected from both the digitalIn and the analogIn is from the same stretch of time? I have data going into the both scopes on the Analog Discovery 2 and data going into 5 of the digitalIn inputs. I am trying to use the external trigger T1 to trigger both analog and digital data collection. I am doing this through python. from ctypes import * from dwfconstants import * import time import matplotlib.pyplot as plt import sys import numpy def analogSetup(dwf, hdwf, analogFreq, nSamples, trigSeconds): dwf.FDwfAnalogInChannelEnableSet(hdwf, c_int(0), c_int(1)) dwf.FDwfAnalogInChannelEnableSet(hdwf, c_int(1), c_int(1)) dwf.FDwfAnalogInTriggerSourceSet(hdwf, c_ubyte(11)) # 11 = external trigger T1 dwf.FDwfAnalogInChannelRangeSet(hdwf, c_int(0), c_double(20)) dwf.FDwfAnalogOutNodeOffsetSet(hdwf, c_int(1), c_double(-10)) dwf.FDwfAnalogInFrequencySet(hdwf, analogFreq) dwf.FDwfAnalogInTriggerPositionSet(hdwf, c_double(trigSeconds)) def digitalSetup(dwf, hdwf, digitalFreq, nSamples, hzDI, trigSamples): dwf.FDwfDigitalInInternalClockInfo(hdwf, byref(hzDI)) print("DigitanIn base freq: "+str(hzDI.value)) divider = int(hzDI.value/digitalFreq) dwf.FDwfDigitalInDividerSet(hdwf, c_int(divider)) dwf.FDwfDigitalInSampleFormatSet(hdwf, c_int(16)) # 16bit per sample format dwf.FDwfDigitalInTriggerSourceSet(hdwf, c_ubyte(11)) # digital trigger with T1 dwf.FDwfDigitalInBufferSizeSet(hdwf, c_int(nSamples)) # set number of sample to acquire dwf.FDwfDigitalInTriggerPositionSet(hdwf, c_int(trigSamples)) # set number of sample to acquire after trigger def triggerSetup(dwf, hdwf): dwf.FDwfAnalogInTriggerAutoTimeoutSet(hdwf, c_double(10)) # 10 second auto trigger timeout dwf.FDwfAnalogInTriggerTypeSet(hdwf, c_int(0)) # trigtypeEdge dwf.FDwfAnalogInTriggerChannelSet(hdwf, c_int(0)) # channel 1 dwf.FDwfAnalogInTriggerLevelSet(hdwf, c_double(5)) # 5V max dwf.FDwfAnalogInTriggerHysteresisSet(hdwf, c_double(0.01)) # 0.01V dwf.FDwfAnalogInTriggerConditionSet(hdwf, c_int(0)) # trigcondRisingPositive def frameRequest(dwf, hdwf): dwf.FDwfAnalogOutNodeEnableSet(hdwf, c_int(0), c_int(0), c_bool(True)) dwf.FDwfAnalogOutNodeFunctionSet(hdwf, c_int(0), c_int(0), funcPulse) dwf.FDwfAnalogOutNodeFrequencySet(hdwf, c_int(0), c_int(0), c_double(50000)) dwf.FDwfAnalogOutNodeOffsetSet(hdwf, c_int(0), c_int(0), c_double(0)) dwf.FDwfAnalogOutNodeAmplitudeSet(hdwf, c_int(0), c_int(0), c_double(float(3.3))) dwf.FDwfAnalogOutWaitSet(hdwf, c_int(0), c_double(5)) # wait length dwf.FDwfAnalogOutNodeSymmetrySet(hdwf, c_int(0), AnalogOutNodeCarrier, c_double(2)) dwf.FDwfAnalogOutConfigure(hdwf, c_int(0), c_bool(True)) if sys.platform.startswith("win"): dwf = cdll.LoadLibrary("dwf.dll") elif sys.platform.startswith("darwin"): dwf = cdll.LoadLibrary("/Library/Frameworks/dwf.framework/dwf") else: dwf = cdll.LoadLibrary("libdwf.so") #declare ctype variables hdwf = c_int() sts = c_byte() sts_d = c_byte() hzAcq = c_double(10e6) DIG_ACQ_FREQ = 10e6 AN_ACQ_FREQ = 10e6 nSamples = 1000 nSamples_d = 1000 rgdSamples1 = (c_double*nSamples)() rgdSamples2 = (c_double*nSamples)() rgwSamples = (c_uint16*int(nSamples))() cAvailable = c_int() cAvailable_d = c_int() cLost = c_int() cCorrupted = c_int() fLost = 0 fCorrupted = 0 hzDI = c_double() trigSamples = int(nSamples/2) # Digital Samples are number of samples after we see the trigger trigSeconds = (1.0/int(hzAcq.value))*(nSamples-trigSamples) # Analog samples are seeing the trigger at this time #print DWF version version = create_string_buffer(16) dwf.FDwfGetVersion(version) print("DWF Version: "+str(version.value)) #open device print("Opening first device") if dwf.FDwfDeviceOpen(c_int(-1), byref(hdwf)) != 1 or hdwf.value == hdwfNone.value: szerr = create_string_buffer(512) dwf.FDwfGetLastErrorMsg(szerr) print(str(szerr.value)) print("failed to open device") quit() print("Digital Setup") digitalSetup(dwf, hdwf, DIG_ACQ_FREQ, nSamples, hzDI,trigSamples) print("Analog Setup") analogSetup(dwf, hdwf, hzAcq, nSamples,trigSeconds) print("Starting oscilloscope") dwf.FDwfDigitalInConfigure(hdwf, c_int(0), c_int(1)) dwf.FDwfAnalogInConfigure(hdwf, c_int(0), c_int(1)) print("Frame Request") frameRequest(dwf, hdwf) sts_a = c_byte() while True: dwf.FDwfDigitalInStatus(hdwf, c_int(1), byref(sts)) dwf.FDwfAnalogInStatus(hdwf, c_int(1), byref(sts_a)) print("Digital Status:", str(sts.value)) print("Analog Status:", str(sts_a.value)) if sts.value == 2 & sts_a.value == 2: # done break time.sleep(1) print("Digital and Analog done") dwf.FDwfDigitalInStatusData(hdwf, rgwSamples, 2*nSamples) # Need to do 2*samples because this function is in bytes dwf.FDwfAnalogInStatusData(hdwf, c_int(0), rgdSamples1, nSamples) dwf.FDwfAnalogInStatusData(hdwf, c_int(1), rgdSamples2, nSamples) dwf.FDwfAnalogOutReset(hdwf, c_int(0)) dwf.FDwfAnalogInReset(hdwf) dwf.FDwfDigitalInReset(hdwf) dwf.FDwfDeviceCloseAll() print("Recording done") dsamples_mask =[] for i in range(len(rgwSamples)): dsamples_mask.append(int(rgwSamples[i]) & 0b10000) plt.plot(numpy.fromiter(dsamples_mask, dtype = numpy.uint16)) plt.plot(numpy.fromiter(rgdSamples1, dtype = numpy.float64), color='orange') plt.plot(numpy.fromiter(rgdSamples2, dtype = numpy.float64), color = 'green') plt.show() This is what I have so far. I tried to use some math to figure out what the trigger positions is supposed to be given a digital trigger position, but that hasn't really worked out. The best I can get is shifting around the analog and digital plot by changing the triggerPositionSet value, but I need it so that both digital and analog is captured at the exact same time. For the thing I'm measuring, I KNOW that the analog and digital lines up, I just can't figure it out in code. Please let me know if any clarification is needed.