What to use for "CW Extra Settings -> Clock Source"

What values should I use for: “CW Extra Settings -> Clock Source”?
What does it do? What is it’s purpose?

I am trying to capture some traces however I am always getting a timeout waiting for the trigger signal, so I am wondering if this is the cause of the timeout.

I have my trigger line connected to the 20pin target connection.
I also have a ground connected to 20pin target connector.
I am providing the clock to the target via the clock output on the 20pin target connector.

In my DUT I set keep the line low usually and set it high during the crypto process.

In the capture software I have:

  • Trigger Setup->Source as “digital”
  • Trigger Setup->Mode as “rising edge”
  • “Trigger Module” set as "Basic (Edge/Level).

Also should the “Digital Pin State” how whether the currently selected trigger pin is currently high or low? Because I tried setting and leaving it high in my device, but the “Digital Pin State” always shows as unticked.


The ‘Clock Source’ is the source for the ‘EXTCLK’ input. So when the ADC clock is ‘EXTCLK x4’ for example, that tells you if the EXTCLK comes from the rear panel, the front panel, etc.

If you are outputting a clock it shouldn’t matter. I assume your ADC Clock is set to x1 or x4 the CLKGEN frequency? Is the ADC Clock locked? Even if you aren’t using the ADC I think the clock forms part of the trigger logic (since the trigger would need to be resynced to the ADC clock domain). If it isn’t locked click the ‘reset DCM’ button.

The ‘Digital Pin State’ should change with IO level, so that is a good troubleshooting tool! There is all the checkboxes that form the input mux for the digital level - did you ensure the ‘Target IO4’ is the only option checked (assuming you are using that pin)? The ‘Digital Pin State’ checkbox will update every ~250mS, so it might miss a short trigger, but if you are manually pulling the pin high/low will catch that.


I am sure the clock is ok because my device is running from it and I can see it answering encryption requests using the simple serial protocol. The Aquisition Monitor is showing correct textin/textout values.

The trigger is just not occurring for some reason, I see it timeout. If I set it to trigger on low then it will trigger immediately. It’s as if the trigger line is not going high and just always being low. The state of the “digital pin” tickbox also suggests it is not going high. I did check that it was being driven correctly before making up my cable. I will have to desolder those pins to double check it is still being set.


The clock might be OK on the output, but it’s still possible the ADC clock is off, as the clock is further processed before being sent to the ADC. As mentioned if the ADC clock is down the trigger might not occur!

As a quick test of the trigger - set the trigger source to be the front panel IO pin (use the check boxes to change this). This puts the trigger on the 2-pin connector beside the transformer input SMA. You can see if you can affect the state of the trigger input checkbox then by touching the pin, or pulling it high/low.



Doh, it turns out I was at fault.
I connected the wires incorrectly on the 20pin socket end :stuck_out_tongue:

Once I realised that the “digital pin” thing should show high, it became obvious that it must be an issue with the wiring which it was.

The quick test using the front panel showed that the digital pin status was indeed working correctly. So then I had to undo and reexamine my wiring.

Awesome! Glad you were able to get it working!