Digital Output using dwf API

[stever]

HI,

I am trying to create a custom output pattern  using Digital Discovery.

I have managed to get it to work referencing the python examples but now want to use the dwf api to simplify the code and avoid ctypes.

I believed I had translated all the existing code but I do not get any output.

Please help point me to what I missed - Thanks:

 

bytestream = np.packbits(bytestream)[0:4096] # bytestream is the pattern data to output

dwf_do.enableSet(pin, 1) # enable pin

dwf_do.idleSet(pin, 0) # set idle state to low

dwf_do.typeSet(pin, 1) # set custom for pattern generation

dwf_do.outputSet(pin, 0) # set output type to push-pull

dwf_do.dividerSet(pin, divider) # set output clock rate

dwf_do.dataSet(pin, dwf.create_bitdata_stream(data=bytestream, bits=8, msb_first=False))

dwf_do.repeatSet(1) # just output the pattern once

dwf_do.runSet(8 * len(bytestream) * divider / internal_clock)

dwf_do.configure(1) # start the output

[stever]

OK  - Solved

I had to move the dwf_do.enableSet(pin,1) to after configuring and just before the dwf_do.configure()

[JColvin]

Hi @stever,

Thanks for sharing the solution you found!

Thanks,
JColvin

[stever]

Hi,

There are several beta releases of Waveforms but the dwf API is from August 2018.

Is there a newer version and any documentation on these calls other than the examples.

I have a problem getting analog io, digital in and digital out all working.

I need analog io to set the IO voltages, digital output and digital inputs (recording)

I implemented:

dwf_dio = dwf.DwfDigitalIO()

dwf_aio = dwf.DwfAnalogIO(dwf_dio)

dwf_do = dwf.DwfDigitalOut(dwf_dio)

dwf_di = dwf.DwfDigitalOut(dwf_dio)

but some digital in calls are not recognised.

They are recognised if I just use dwf_di = dwf.DwfDigitalOut() by itself

But with the others then the instantiation fails as the device is in use.

 

Any ideas please ?

[attila]

Hi @stever

I don't know what the Python package are you using but the digital out is not equivalent to digital in, the functions are different, dwf_di /= dwf.DwfDigitalOut

The latest documentation version, corresponding to the sdk version, is included in the application/sdk package.

[stever]

Hi Attila, and thanks for responding.

I am using Pycharm IDE with python 2.7.6

I can now call all the functions after correctly instantiating:

dio = dwf.DwfDigitalIO()

aio = dwf.DwfAnalogIO(dio)

do = dwf.DwfDigitalOut(dio)

di = dwf.DwfDigitalIn(dio)

I am trying to create a pattern on four outputs and capture data in sync on two inputs.

Please review the file I attached and advise.

Thanks

stever

 

digilent pattern.py

[attila]

Hi @stever

Sorry but I'm not familiar with this 3rd party dwf wrapper.
See the WF SDK/ samples/ py/ DigitalOut_CustomBus.py which performs digital-in and out.

[stever]

Hi Atilla,

OK - thanks.

Is there any way that I can stream large files out as a pattern ?

If not, is there a way to make use of the 32k buffers on unused outputs and combine them into a larger buffer for four outputs ?

The pattern I am generating is less than 512k

Thanks

stever

[attila]

Hi @stever

It is not possible, the maximum digital-out buffer size on Digital Discovery is 32k samples / channel