Digital Discovery Stand Alone Operation

[uscusc]

For a project, I’m interested in Digilent products. Mainly Digital Discovery and Pmod GPS module. I intend to use the Digital Discovery modules to generate parallel digital clock-like signals with a frequency around 10 MHz to control a custom built RF Switching circuit. I believe I can use the 16-channel pattern generator to create 3.3V CMOS signals to accomplish that. However, I have the following questions. 

 

I have a distributed system, so I’ll need more than 32 of these units run at different locations. Can these units work stand alone once they are programmed? Can I program these units to create a certain pattern whenever they receive an external trigger? Ideally, I would want to have them programmed once and start operating as soon as they are powered without requiring a USB connection. 

 

I’m planning to use the 1PPS signal from the Pmod GPS receiver to trigger this operation. Would it work and Do you any documentation about the timing accuracy of the 1PPS signal provided by the Pmod GPS module? 

 

Thanks,

 

[jpeyron]

Hi @uscusc,

I have moved your forum thread to scopes & instruments where more Digital Discovery experienced engineers look.  

cheers,

Jon

[attila]

Hi @uscusc

The digital outputs can be configured from WaveForms application Pattern Generator interface to output a pattern based on a trigger.
The Digital Discovery does not have dedicated trigger input but from Logic Analyzer any digital IO or input pin can be used, and Pattern configured to trigger on this Logic trigger.
The device can also be controlled by custom application or script based on WaveForms SDK.

The instrumentation devices (EExplorer, Analog/Digital Discovery) have no flash to store the configuration, these need to be configured after poweron.

Regarding the GPS please see the pmod reference and module manual:
https://reference.digilentinc.com/reference/pmod/pmodgps/start
https://reference.digilentinc.com/_media/reference/pmod/pmodgps/globaltop-fgpmmopa6h-datasheet-v0a.pdf

[Knut]

On 9/11/2017 at 12:10 PM, attila said:

The Digital Discovery does not have dedicated trigger input but from Logic Analyzer any digital IO or input pin can be used, and Pattern configured to trigger on this Logic trigger.

Could you please explain how to do that? I can't find a way to establish a link from the Logic Analyzer to the Pattern Generator in the Digital Discovery. I can select "Logic" as a trigger option with "Edge" in Pattern, but I can't find where I can point to my setup in Logic from Pattern to use Logic as a trigger source.

[attila]

Hi @Knut

The Patterns can be trigger by Logic analyzer like this:
Logic triggers on DIN0 rising edge, Patterns triggers on Logic and outputs high for 1ms.

It looks like on Digital Discovery the Patterns triggering by Logic is broken since v3.6.x
You have in private message version fixing this issue.
 

[Piotr Rzeszut]

Hi, @uscusc. You can try using Raspberry Pi to make AD2/DD a kind of "standalone".

[attila]

Hi @Piotr Rzeszut, @uscusc

AD1/2/DD is working with many ARM devices, but not with Raspberry PI 1/2/3 B.

 

[Piotr Rzeszut]

Hi @attila,

So which ARM device (with WiFi support) you suggest using for the purpose?

[attila]

Hi @Piotr Rzeszut

I only tested Zed, Zybo, BeagleBone Black but others say with OrangePi it is also working.

 

[ramestica]

is it triggering by Logic in Digital Discovery Patterns still broken since v3.6.x? I'm trying the demo device on version 3.8.2, and I cannot understand how to associate in Patterns an specific Logic trigger. Is it the Parameter pull down menu somewhat meant to individualize which logic trigger to apply?

[Piotr Rzeszut]

If you are using WaveForms without a physical device (i.e. in DEMO mode) some functions are not simulated.

[attila]

Hi @ramestica

As Piotr said, not all the functions are simulated in demo mode. Triggering is not working in demo.