using external trigger as sample clock

[masker]

Hi,

I have an ADP3450 using the SDK in linux mode. 

I want to use an external trigger signal to capture one sample from the AnalogIn channels for each trigger positve edge.

The external trigger pulses are not at a constant rate and may separated by 1us to 100us. I would like to capture upto 100k samples in a single run and then download the measurements. 

I've been playing around with the GUI but can't workout if it is possible to use an external signal to make a single sample. Do you have any suggestions on how I can do this? I saw reference to  'Sync' mode but couldn't see any details.

cheers  Mike

[attila]

Hi @masker

See FDwfAnalogInSamplingSource/Slope/Delay/Set in the WF SDK manual.pdf or dwf.h

[masker]

Thanks for the quick reply.  I see it in the documentation and will give it a try.

Is there a way to try this in the gui? Its seems easier to prove it out in the gui first then switch to the sdk. 

In the waveform help I see Sampling Clock, but in my software version 3.16.3 this doesn't exist.

cheers  -mike

[attila]

Hi @masker

I recommend to use the latest version:
As you can see these bring new features, fixes and rarely bugs.

 

[masker]

Thanks, I installed 3.18.18 but I still don't see the Sampling Clock setting as shown in the documentation '3.1 Time Group' . Am I looking in the wrong place?

 

cheers  -mike

[masker]

Hi attila, I've been trying to use the FDwfAnalogInSamplingSourceSet but I'm not having much luck. I've tried many different settings. Would you be able to tell where I'm going wrong with my script please? (see attached)

In the script I print out the 16 sample values (see sSamples below) which should match the values in the staircase waveform shown below.

 

 

cheers  -mike

 

AnalogIn_Trigger2.py

[attila]

Hi @masker

The sampling clock option is added for ADP3X50 only in the latest version:
digilent.waveforms.adp3X50_3.18.19_armhf.deb

 

[masker]

Hi Attila,

Thanks, I really appreciate your help!  I'll give that one a go and let you know.

Curious how did you know I was using an arm? 

I'm using the sdk on an arm (raspberry pi) over usb, and also using the waveforms gui on a PC over ethernet on the same adp3450.

cheers

-mike

[attila]

Hi @masker

Are you using 32 or 64bit Linux or RPI? Do you need armhf or arm64?

The d.w.adp3X50.debs are intended to be used on ADP3X50 with embedded Linux mode. These don't contain the GUI (WF app).
The d.w.armhf.deb packages are intended for RPI, BBB... but these can also be installed on ADP3X50 if you want GUI. Since version 3.17.21 these debs also includes AXI/high-speed in device instrumentation access.
Since version 3.17.21 the adp3X50 packages (due to the dynamic AXI access) may also work on other boards but I didn't try this.

 

[masker]

Hi Attila, We're using an RPI arm with ubuntu server 20.04.3 64bit,  Do you have the arm 64 bit version?  cheers -mike

[masker]

also, my IT guy who is doing the builds and installs said he needed to install the adept software as well as the waveforms arm64.deb , probably some dependency. -mike

[attila]

Hi @masker

digilent.waveforms_beta_3.18.19_arm64.deb

Adept Runtime can be found here: https://mautic.digilentinc.com/adept-runtime-download
https://digilent.com/reference/software/adept/start

PS: Sorry but in the first replies I forgot that trigger sampling was not supported by ADP. I thought the reference clock option will be better and suffice but this has a different use case.

[masker]

Hi Attila,

Thanks! no problem I appreciate your response!

Good news, arm64 3.18.19 seems to be working! I am reading out the samples with the correct values

Will you be having an example py file at some time? Having an example of doing it the right way would be very useful. (you can use mine if its of any use)

I took a look at your latest AnalogInOut_RecordPlay.py, I think the acqmodeRecord streaming mode could be more useful to me, (I've been using acqmodeScanShift so far)

thanks again

-mike

[attila]

Hi @masker

Most of the examples can be used with sampling clock.
The FDwfAnalogInSamplingSourceSet should be set and eventually the Slope and Delay if other than Rising edge or 0ns delay is desired.
This being set, FDwfAnalogInFrequencySet is ignored and Average filter is unavailable so Decimate will be used instead. 

[masker]

A note to others running in sample mode, it seems you need to run the FDwfAnalogInStatus function before reading back any data.