MSO Vertical Resolution in Automation API

Logic MSO
1

Hi,

I have just received the Saleae MSO (4 channel 100MHz 9-bit) and I like it so far along with the Logic 2 software!

I have started developing my automation setup using Saleae MSO but I am running into one possible limitation. I am trying to measure signals like power supply ripple which is in the range of tens of millivolts. I can see this clearly when using Logic 2 software and I can easily set trigger to it but this doesn’t seem to be possible with the Python API.

I tried with the center_voltage and voltage_range parameters but these doesn’t seem to actually affect the analog front end (AFE) of the MSO. Even when changing these settings I seem to get least significant bit (LSB) resolution of about 20mV. This would make sense as per my understanding the default voltage range for the analog channels in 10V which divided by 9 bits leads to about 20mV.

I have checked this forum post about the AFE and Logic 2 interaction and what I can understand is that the Logic 2 determines which AFE setting to choose. This would mean that the AFE settings need the Logic 2 to be configured for the best possible resolution. I did also try the “Fixed Range“ setting which didn’t help. As the API doesn’t utilize the Logic 2 software I have come to the conclusion that (as of writing) it is not possible to configure the AFE or vertical resolution with the Python API.

My questions:

  1. Is there a way to get better resolution than 20mV when using MSO and Python automation API?
  2. If this is not possible currently with the public API would this be somewhat simple to implement myself with the SDK? Assuming this feature is not planned for near future update for the API.
  3. As the MSO seems to rely heavily on the Logic 2 software (obviously) is there a timeline for integrating the API to use the Logic 2. I have used the Logic analyzers from Saleae in automation and they specifically need the Logic 2 to be running (as the MSO specifically needs it to be closed to avoid connection conflicts) and I assume that in that case the API can better utilize the software tricks used in Logic 2. I saw in a different post that this is planned but not with high priority. I myself would find this beneficial. Even just the fact that I could see the capture status by glancing and Logic 2 to see if it triggers or not is great. Also quickly manually checking the best configuration for captures I am about to run with automation without closing and reopening the software is a quality of life improvement.

Thanks in advance and keep up to good work!

regards,

Niko

2

Hi Niko,

Sorry you are having trouble with this!

Is there a way to get better resolution than 20mV when using MSO and Python automation API?

Yes, you should be able to control the AFE from mso-api like you would in Logic 2 itself. Would you be able to share the full configuration you are using so I can try to reproduce over here?

As the MSO seems to rely heavily on the Logic 2 software (obviously) is there a timeline for integrating the API to use the Logic 2. I have used the Logic analyzers from Saleae in automation and they specifically need the Logic 2 to be running (as the MSO specifically needs it to be closed to avoid connection conflicts) and I assume that in that case the API can better utilize the software tricks used in Logic 2. I saw in a different post that this is planned but not with high priority. I myself would find this beneficial. Even just the fact that I could see the capture status by glancing and Logic 2 to see if it triggers or not is great. Also quickly manually checking the best configuration for captures I am about to run with automation without closing and reopening the software is a quality of life improvement.

We don’t currently have an official timeline, but this is the plan. Thanks for the example use-cases - I’ve had the same experience myself

Ryan

3

Hi Ryan,

Thanks for the swift reply. I have reviewed my code and noticed a mistake and was able to fix it. Now I am able to change the resolution.

Do you see any risk with backwards compatibility when you integrate the Logic 2 to the MSO API? Should I expect for my code to break when you implement this feature?

-Niko

4

Hi Niko,

Glad you were able to resolve the issue.

Do you see any risk with backwards compatibility when you integrate the Logic 2 to the MSO API? Should I expect for my code to break when you implement this feature?

I don’t know if the logic2-automation API will match, but I expect that we will somehow support the current mso-api API through a wrapper or by continuing to release updates for it (at least for some period of time, giving an opportunity to migrate over).

Ryan

5

Hi Ryan,

thanks for the insights. This problem can be closed.

Niko