Output DC voltage of digital on DigitalDiscovery

[laurent]

Hi,

With Waveforms, I can output the DC voltage of the digital signals, i.e. 3.3V on DigitalDiscovery.

But with a python script, I use :

# set voltage to 3.3 V (DD)
dwf.FDwfAnalogIOChannelNodeSet(hdwf, 0, 0, c_double(3.3))
# enable positive supply
dwf.FDwfAnalogIOEnableSet(hdwf, 1) # enable VIO

 

But, I cannot the get the 3.3V voltage reference. What is missing ?

Thanks, BRgds,

Laurent

[attila]

Hi @laurent

In case your script quits the device gets closed and the outputs stopped.
Set the following parameter before opening the device to keep it running on quit/close:
dwf.FDwfParamSet(DwfParamOnClose, c_int(0)) # 0 = run, 1 = stop, 2 = shutdown

The VIO could be stopped due to over-current.
See the SDK/ samples/ py/ AnalogIO_DigitalDiscovery.py

Edited February 20, 2020 by attila

[Alessandro]

Hi,
I have the same problem here. In particular I used the DigitalOut_Custom python code, but with the oscilloscope I realized I can't reach 1V output and I need more.
Therefore before declaring the variable "pin=0", I put:

# set voltage to 3.3 V (DD)
dwf.FDwfAnalogIOChannelNodeSet(hdwf, 0, 0, c_double(3.3))
# enable positive supply
dwf.FDwfAnalogIOEnableSet(hdwf, 1) # enable VIO"

but nothing has changed. Any suggestions?
Thank you.

 

[attila]

Hi @Alessandro

Which device are you using?
The VIO voltage can be adjusted on Digital Discovery and ADP3X50 but not on Analog Discovery. See the SDK manual pdf

If you have dwf.FDwfDeviceAutoConfigureSet(hdwf, c_int(0)) set then call dwf.FDwfAnalogIOConfigure(hdwf)

 

Edited March 2, 2022 by attila

[Alessandro]

I'm using Analog Discovery 2. Examining the digital channels, I can see they're synchronous, but they show 500mV as maximum voltage.
I don't know if there's a possibility to obtain perfect synchronous channels with greater voltage range...

[attila]

Hi @Alessandro

What load do you have on the DIOs?

Eventually you could use the Wavegen output(s) for stronger drive.