Digilent's DWF Library wrapper for python

What is this?

This is a python library for controlling Analog Discovery and Electronics Explorer series presetned by Digilent inc. This library needs Waveforms SDK.

I tested this library with Analog Discovery 2 and Waveforms 2015 in below environment.

• python 3.5.1, python 2.7.10 on OSX 10.11
• python 3.4.3, python 2.7.6 on Ubuntu 14.04LTS
• python 3.5.1 on Windows 7

I wrote this library for supporting python 2.6, 2.7, 3.3 or above.

This software is released under the MIT License, see LICENSE.txt.

Installing

You can install the latest stable version from PyPI:

pip install dwf

or if you prefer, install it from this repo like this:

python setup.py install

API of this library

This library has two sets of API. There are Function-based API and Class-based API.

Function-based API

This API is like as C functions which supplied by Digilent. But some modifications are applied for pythonic-way programming.

1. When error is returned by SDK, the exception DWFError is raised.
2. All output values, which are passed by reference, are changed to return-value of function.
3. Arrays of parameters are converted from/to python's list.

Examples

SDK version check in C language is like as:

char version[32];
FDwfGetVersion(version);
printf("DWF version: %s\n", version);

With this library using function-based API, same code is translated to:

version = dwf.FDwfGetVersion()
print("DWF version: " + version)

Another example is here. This piece of code is quoted from analogout_custom.c in Waveforms SDK sample.

HDWF hdwf;
double rgdSamples[4096];
for (int i = 0; i < 4096; i++) rgdSamples[i] = 2.0*i/4095-1;

FDwfDeviceOpen(-1, &hdwf);
FDwfAnalogOutNodeSet(hdwf, 0, AnalogOutNodeCarrier, true);
FDwfAnalogOutNodeFunctionSet(hdwf, 0, AnalogOutNodeCarrier, funcCustom);
FDwfAnalogOutNodeDataSet(hdwf, 0, AnalogOutNodeCarrier, rgdSamples, 4096);
...

In python with this library, like as:

rgdSamples = []
for i in range(4096): rgdSamples.append(2.0*i/4095-1)

hdwf = dwf.FDwfDeviceOpen()
dwf.FDwfAnalogOutNodeSet(hdwf, 0, dwf.AnalogOutNodeCarrier, True)
dwf.FDwfAnalogOutNodeFunctionSet(hdwf, 0, dwf.AnalogOutNodeCarrier, dwf.funcCustom)
dwf.FDwfAnalogOutNodeDataSet(hdwf, 0, dwf.AnalogOutNodeCarrier, rgdSamples)
...

Class-based API

Class-based APIs are made from function-based APIs. Documents of this API is now writing.

This API has below function and classes.

DwfEnumeration()

Device enumeration. This function returns list of DwfDevice.

class DwfDevice

call FDwfEnum*() functions.

class Dwf

call FDwfDevice*() functions.

class DwfAnalogIn

call FDwfAnalogIn*() functions.

class DwfAnalogOut

call FDwfAnalogOut*() functions.

class DwfAnalogIO

call FDwfAnalogIO*() functions.

class DwfDigitalIO

call FDwfDigitalIO*() functions.

class DwfDigitalIn

call FDwfDigitalIn*() functions.

class DwfDigitalOut

call FDwfDigitalOut*() functions.

With this API, example code is translated to

rgdSamples = []
for i in range(4096): rgdSamples.append(2.0*i/4095-1)

dwf_ao = dwf.DwfAnalogOut()
dwf_ao.nodeSet(0, dwf_ao.NODE.CARRIER, True)
dwf_ao.nodeFunctionSet(0, dwf_ao.NODE.CARRIER, dwf_ao.FUNC.CUSTOM)
dwf_ao.nodeDataSet(0, dwf_ao.NODE.CARRIER, rgdSamples)
...