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Altera_Forum's avatar
Altera_Forum
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16 years ago

Signaltap II

Hi!

I have two doubts.

I have a proyect and I have created a *.stp file.

I haven't used trigers conditions.

The problem is that I want to see the captured dates continously in a 10ms time.

and the windows in signaltap II only show 128 samples.

I use a 40MHz clock.

¿what I have to do to capture in the same windows or same log 10ms????

and the second doubt is:

¿can I capture two signals in signaltab in a vector in order to use them later with matlab????

many thanks in advance for your help.

14 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    When you created the signaltap you had an option to define the sample depth, in your case 128, which will give you 128 * 25ns or 3.2us. So in order to show 10ms you are going to need to set the depth to a much larger value which I suspect will be impractical. Could you use a slower clock to capture the data?

  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    to capture data from signaltap into text file:

    set all data to signed(or unsigned, not hex). Then right click mouse and click on generate text file(not sure of actual menu title). Then open text file and remove any text header leaving only the coulmns.

    Now it is ready to be read in matlab by typing:

    load filename.txt

    (make sure the directory is set for matlab). This generates a matrix of data called filename,then read any of its column(each couln refers to a signal or bit of a bus, so make sure which column to read):

    data1 = filename(:,1); %all rows of column 1
  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    you can also use a MATLAB command to capture signals from signal tap directly into a vector\matrix. using a loop you can achieve a greater depth.

    but it will probably be safer to use triggers.

    use the command:

    data= alt_signaltap_run ( 'stp_file_name.stp', 'unsigned');
  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    Hi BEN

    I cant use a slow clock. :S

    ¿Is there another option without using a slow clock???'

    Hi Kaz!

    If I do what you say it only capture the 128 samples showed in the windows and I want a vector of 10ms.

    ¿what can I do??

    Hi the brick

    I cant understand. Can you explain me exactely what you mean?? or give me some reference or any link?

    thanks every one.
  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    If you can't use a slower clock then you'll have to increase the sample depth though like I said I doubt you'll be able it enough to cover 10ms.

  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    Hi Ben

    Oks I will try to increase the sample depth but

    I what to know if I can use another tool or method to capture a signal during a long time and see it in a window??

    Or is this imposible?
  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    If you have access to a logic analyser then you might be able to use that as they generally have larger sample depths but otherwise you will be constrained by the amount of ram you have available in your fpga.

  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    Thanks for your help. I think that I understand you.

    But, do you know if there is another method with jtag connection to view a signal during "infinite" time in the same window?:(
  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    1. The number of samples can be set to a power of two up to 128k, if you have sufficient on-chip memory available. You did neither tell the involved FPGA type nor the signal width, so we can't know the maximum setting. But SignalTap informs about the RAM utilisation, so you can set it to the maximum possible value.

    2. 10ms at 40 MHz would mean 400k samples. This sample size isn't supported by SignalTap. Besides using a slower clock, you can also enable a storage qualifier to reduce the sample frequency.

    3. A continuously sustained acquisition at a high sampling frequency is basically impossible due to the limited JTAG throughput. Even at slower speeds, it would require an interleaved sampling and JTAG transmission scheme, not supported by SignalTap as far as I know.
  • Altera_Forum's avatar
    Altera_Forum
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    16 years ago

    I meant you can import data directly into MATLAB without using the QUARTUS for capture (you will need it to create the stp file).

    look in the MATLAB help about the alt_signaltap_run command for more info.

    but as FvM said, you are limited by JTAG throughput (I have 1 Mbs in mind, but I'm not sure) , so you should better limit the data you need to transfer, use trigger conditions to "zoom in" on what intersts you.