No constant type in Waveforms API

[sand]

Hello!

I am programming an Analog Discovery 2 with the Waveforms API in Python 3, and I am wanting to use the "Patterns" generator to make DIO-0 go to state '1'. In the SDK I only see the following options (from the SDK reference manual):

• DwfDigitalOutTypePulse: Frequency = internal frequency/divider/(low + high counter).
• DwfDigitalOutTypeCustom: Sample rate = internal frequency / divider.
• DwfDigitalOutTypeRandom: Random update rate = internal frequency/divider/counter alternating between low and high values.
• DwfDigitalOutTypeROM: ROM logic, the DIO input value is used as address for output value
• DwfDigitalOutTypePlay: Supported with Digital Discovery.

 

But the Waveforms software allows the type "constant". Is there a way to make the pin a constant logical high while the program is running?

[JColvin]

Hi @sand,

You'll be wanting FDwfDigitalIOOutputEnableSet and FDwfDigitalIOOutputSet which are defined in the Digital IO section (section 8) of the WaveForms SDK Reference Manual.

DigitalIO.py in the samples folder uses these two functions, enabling DIO 0 to 7 as outputs and then setting IO pins 2 and 5 as logic high.

Let me know if you have any questions (or if I misunderstood what you are wanting to do).

Thanks,
JColvin

[attila]

Hi @sand

The easier is to use Digital/StaticIO functions.
For constant with DigitalOut use Counter 0|0 and specify (initial) value with CounterInit

dwf.FDwfDigitalOutEnableSet(hdwf, channel, 1)
# dwf.FDwfDigitalOutIdleSet(hdwf, channel, DwfDigitalOutIdleInit) # default value
dwf.FDwfDigitalOutCounterInitSet(hdwf, channel, 1, 0) # 1 = initialize with high when running
dwf.FDwfDigitalOutCounterSet(hdwf, channel, 0, 0) # low/high count zero, no toggle during run, constant

[sand]

I went with the answer by @attila, but I think @JColvin's method would work, too. Thanks to both of you!

[JColvin]

Good choice; only one of us is the WaveForms developer and its not me.