waveforms SDK adding custom pattern to digital discovery

[menach_g]

I'm trying to use output a custom pattern contained in csv format out of a digital discovery.

I succeeded doing so using the program and adding manually, now I want to do this in python using the sdk.

I can see the function I need to use is "FDwfDigitalOutDataSet" but I don't seem to get it working.

the only example on custom data is on the analog discovery and it doesn't seem to be the same.
 

here is the code I try running

from ctypes import *
from dwfconstants import *
import math
import time
import matplotlib.pyplot as plt
import sys


dwf = cdll.dwf

hdwf = c_int()
sts = c_byte()

version = create_string_buffer(16)
dwf.FDwfGetVersion(version)
print("DWF Version: " + str(version.value))

print("Opening first device")
dwf.FDwfDeviceOpen(c_int(-1), byref(hdwf))

if hdwf.value == 0:
    print("failed to open device")
    szerr = create_string_buffer(512)
    dwf.FDwfGetLastErrorMsg(szerr)
    print(str(szerr.value))
    quit()

hzSys = c_double()
dwf.FDwfDigitalOutInternalClockInfo(hdwf, byref(hzSys))
print("Internal frequency is " + str(hzSys.value / 1e6) + " MHz")

# 100kHz counter rate, SystemFrequency/100kHz
cntFreq = c_uint(int(hzSys.value / 10e6))


data_py=[0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1]

data=(c_int*len(data_py))()

# for i in range(0,len(data)):
#     data[i] = 1.0*i/len(data_py);
for i in range(len(data_py)):
    data[i]=c_int( data_py[i])

pin=0
# generate pattern
dwf.FDwfDigitalOutEnableSet(hdwf, c_int(pin), c_int(1))
dwf.FDwfDigitalOutOutputSet(hdwf, c_int(pin),c_int(3))
dwf.FDwfDigitalOutDataSet(hdwf,c_int(pin),data,c_int(len(data)))




dwf.FDwfDigitalOutConfigure(hdwf, c_int(pin),c_int(1))

print("Generating pattern...")
time.sleep(10)

dwf.FDwfDigitalOutReset(hdwf)
dwf.FDwfDeviceCloseAll()

if anyone have an example of a working patterns code using custom pattern is would be much appreciated

[attila]

Hi @menach_g

1. The FDwfDigitalOutDataSet expects of bits. See the code below. 

2. With FDwfDigitalOutOutputSet(.. .3) did you wanted ThreeState ?
In this case the bits will represent: value, output-enable, value....

3. No need for pin argument in FDwfDigitalOutConfigure

4. You forgot to specify the frequency with FDwfDigitalOutDividerSet

See the WF SDK manual and examples. 

from ctypes import *
from dwfconstants import *
import sys
import time

if sys.platform.startswith("win"):
    dwf = cdll.dwf
elif sys.platform.startswith("darwin"):
    dwf = cdll.LoadLibrary("/Library/Frameworks/dwf.framework/dwf")
else:
    dwf = cdll.LoadLibrary("libdwf.so")

hdwf = c_int()

version = create_string_buffer(16)
dwf.FDwfGetVersion(version)
print("DWF Version: "+str(version.value))


print("Opening first device")
dwf.FDwfDeviceOpen(c_int(-1), byref(hdwf))

if hdwf.value == 0:
    print("failed to open device")
    szerr = create_string_buffer(512)
    dwf.FDwfGetLastErrorMsg(szerr)
    print(str(szerr.value))
    quit()

print("Configuring Digital Out")

hzSys = c_double()
dwf.FDwfDigitalOutInternalClockInfo(hdwf, byref(hzSys))


data_py=[0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1]

# how many bytes we need to fit this many bits, (+7)/8
rgbdata=(c_ubyte*((len(data_py)+7)>>3))(0) 

# array to bits in byte array
for i in range(len(data_py)):
    if data_py[i] != 0:
        rgbdata[i>>3] |= 1<<(i&7)
        
        
pin=0
# generate pattern
dwf.FDwfDigitalOutEnableSet(hdwf, c_int(pin), c_int(1))
dwf.FDwfDigitalOutTypeSet(hdwf, c_int(pin), DwfDigitalOutTypeCustom)
# 100kHz sample rate
dwf.FDwfDigitalOutDividerSet(hdwf, c_int(pin), c_int(int(hzSys.value/100e3))) # set sample rate
dwf.FDwfDigitalOutDataSet(hdwf, c_int(pin), byref(rgbdata), c_int(len(data_py)))


print("Generating pattern...")
dwf.FDwfDigitalOutConfigure(hdwf, c_int(1))

time.sleep(10)

dwf.FDwfDigitalOutReset(hdwf)
dwf.FDwfDeviceCloseAll()

 

[menach_g]

16 hours ago, attila said:

Hi @menach_g

1. The FDwfDigitalOutDataSet expects of bits. See the code below. 

2. With FDwfDigitalOutOutputSet(.. .3) did you wanted ThreeState ?
In this case the bits will represent: value, output-enable, value....

3. No need for pin argument in FDwfDigitalOutConfigure

4. You forgot to specify the frequency with FDwfDigitalOutDividerSet

See the WF SDK manual and examples. 

from ctypes import *
from dwfconstants import *
import sys
import time

if sys.platform.startswith("win"):
    dwf = cdll.dwf
elif sys.platform.startswith("darwin"):
    dwf = cdll.LoadLibrary("/Library/Frameworks/dwf.framework/dwf")
else:
    dwf = cdll.LoadLibrary("libdwf.so")

hdwf = c_int()

version = create_string_buffer(16)
dwf.FDwfGetVersion(version)
print("DWF Version: "+str(version.value))


print("Opening first device")
dwf.FDwfDeviceOpen(c_int(-1), byref(hdwf))

if hdwf.value == 0:
    print("failed to open device")
    szerr = create_string_buffer(512)
    dwf.FDwfGetLastErrorMsg(szerr)
    print(str(szerr.value))
    quit()

print("Configuring Digital Out")

hzSys = c_double()
dwf.FDwfDigitalOutInternalClockInfo(hdwf, byref(hzSys))


data_py=[0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1,0,1]

# how many bytes we need to fit this many bits, (+7)/8
rgbdata=(c_ubyte*((len(data_py)+7)>>3))(0) 

# array to bits in byte array
for i in range(len(data_py)):
    if data_py[i] != 0:
        rgbdata[i>>3] |= 1<<(i&7)
        
        
pin=0
# generate pattern
dwf.FDwfDigitalOutEnableSet(hdwf, c_int(pin), c_int(1))
dwf.FDwfDigitalOutTypeSet(hdwf, c_int(pin), DwfDigitalOutTypeCustom)
# 100kHz sample rate
dwf.FDwfDigitalOutDividerSet(hdwf, c_int(pin), c_int(int(hzSys.value/100e3))) # set sample rate
dwf.FDwfDigitalOutDataSet(hdwf, c_int(pin), byref(rgbdata), c_int(len(data_py)))


print("Generating pattern...")
dwf.FDwfDigitalOutConfigure(hdwf, c_int(1))

time.sleep(10)

dwf.FDwfDigitalOutReset(hdwf)
dwf.FDwfDeviceCloseAll()

 

thank you very much
I finally got it working since then using the example "DigitalOut_Pins.py" 
do you know if there is a way to input custom data not in byte list format but as a list of bits?

also I can't seem to find a command to set the output volatge like in wf program?
I tried "FDwfAnalogImpedanceAmplitudeSet" which is the closest thing I found, but it doesn't change the output volatge.
 I need it to be set to 1.2v instead of 3.3v.
thnks for the help!

[attila]

Hi @menach_g

See the SDK/ samples/ py/ AnalogIO_DigitalDiscovery.py example and the manual PDF.

# set digital voltage between 1.2 and 3.3V
dwf.FDwfAnalogIOChannelNodeSet(hdwf, c_int(0), c_int(0), c_double(1.8))

 

[menach_g]

 

yes it works for 1.2v thank you very much!
and I need to output more complicated signals than a simple clock
do you know of a way to input the custom data as bit list and not byte list?(yes I know I can add a function to format it that way nut I want to avoid that as I'm dealing with long signals)

[attila]

The conversion is needed. The FDwfDigitalOutDataSet only accepts such compact custom data arrays.
The Digital Discovery digital-out-custom supports up to 32.768 bit-samples / channel (4kB)

[menach_g]

On 9/3/2019 at 4:00 PM, attila said:

The conversion is needed. The FDwfDigitalOutDataSet only accepts such compact custom data arrays.
The Digital Discovery digital-out-custom supports up to 32.768 bit-samples / channel (4kB)

hey @attila 
thanks for all the great help
I got the custom output setup fully working for my implemntation
but now I want to add digitaln reading back using din pins
I want the recording to be in sync with one of the io output channels which is a clock
I got working in wf program like so:

but when I did not find the equivalent functions in the sdk documentation

I tried using snippets of code from "DigitalIn_Sync.py" nut it just goes into infinite loop with "cAvailable.value" == 0 every time..(I would add my code here but some parts like the custom setup are too long for simple code snippets)

do you know how to set up a simple input in sync with custom output in python sdk
your help will be greatly appreciated!!

[attila]

Hi @menach_g

For DIO 24 (Digital Discovery) use:

# trigger detector mask:          low &     hight & ( rising    |   falling )
dwf.FDwfDigitalInTriggerSet(hdwf, c_int(0), c_int(0), c_int(1<<24), c_int(0)) # DIO 24

 

[menach_g]

solved: the problem was made when syncing with a clock and nSamples bigger than clock cycles.
solution: adding exit condition in acquire loop, using FDwfDigitalOutStatus to check if output is done