Forum Discussion
ContributorWhat is the limit on signals in signal tap II
Again, using a state-based trigger or other options I mentioned, you can capture data from multiple subsequent events before the logic analyzer stops, limited by the size of the buffer.
ContributorThanks, my last question has wrong wording. What I want to know is, why does Signal Tap II not allow user to copy signals from one instance to another? Also, copy a whole instance from one signal tap to another?
In my case when signal tap has captured a lot of complex data, I just save the signal tap instance with a different name and then analyse it later. Is this the correct approach?
By bandwidth I mean, is it possible that when there are so many signals in the signal tap II instance and trigger events occur at very high frequency, the programmer cable will not be able to transmit all data before the next trigger event? I am sure this is possible to happen.
Super ContributorCopying signals: simply not a feature that's in the tool. You could request it perhaps.
Again, when a trigger occurs, the logic analyzer stops and buffers the data. The situation you mention does not happen. If you're talking about multiple trigger "conditions" (the condition columns in the tool) the logic analyzer only stops and captures data when the final trigger condition column is true. It does not capture data from the previous trigger condition columns. That's why I said that if you want to capture data from multiple trigger events that occur close to each other, you'd need a state-based trigger (to manually control when data is stored in the buffer so you could store data from each event) or multiple logic analyzer instances.
There's only one buffer for each instance of the logic analyzer and it gets sent to your computer only when the trigger conditions have all occurred. So again, there would never be a bandwidth issue because there is no urgency in sending out the buffer data since you'd have to start the logic analyzer manually to look for the trigger conditions again (at which point the buffer is empty again anyway).
NurinaRegular Contributor
Hi @gyuunyuu,
Did the above reply help you with your problem? Let me know if you have anymore questions.
Regards,
Nurina
P/S: If you find any comments by the community or Intel Support to be helpful, feel free to give Kudos.
- gyuunyuu
Yes this has been helpful. However, I still have a doubt.
Lets suppose that there is 2k buffer depth and the signals on the screen come to 128 bytes. When the trigger condition occurs, all of 2k*128 bytes of data shall be transmitted to the screen and appear on the screen. This is 250kB of data.
If the trigger condition occurs every microsecond, we would need to transmit 250kB of data every microsecond. This shall give 10^6 transfers of 250kB of data per second. This comes to (2000*128)*10^6/(1024^3) GB/s which is about 238.42 GB per second. I am sure that the byte blaster is not capable of transmitting so much data.
I hope that the source of my confusion is clear now.
- sstrell
Again, that's not how Signal Tap works. As soon as a trigger condition occurs, the logic analyzer buffers the signal data and stops. It does not continue looking for another trigger.
If you need to see data from two (or more) events that occur in a short period of time, then you need to adjust the trigger conditions as I mentioned to allow for that data to get stored in the buffer before the logic analyzer stops.
Think of it like a bench logic analyzer, not like a bench oscilloscope.
