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Altera_Forum's avatar
Altera_Forum
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10 years ago

Signaltap retrieve data .... after having plugged JTAG

is it possible to plug the jtag (usb blaster or other) and retrieve captured data (aquire data a postiori) with signaltap?

I mean :

  1. Program a FPGA with SignalTap,

  2. Let the board functionning alone, let internal SignalTap capture data because trigger has occured
  3. Plug USB Blaster

I know there is a power up capture, but I want to retrieve data after an other trigger condition was met.

Is it possible ?

notes :

(1) : Does SignalTap work alone in FPGA = without having to press "Run analysis" ?

(2) : Is there an risk of loosing FPGA configuration when pluggin USB Blaster ?

Cordially.

7 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    10 years ago

    --- Quote Start ---

    is it possible to plug the jtag (usb blaster or other) and retrieve captured data (aquire data a postiori) with signaltap?

    I mean :

    1. Program a FPGA with SignalTap,

    2. Let the board functionning alone, let internal SignalTap capture data because trigger has occured
    3. Plug USB Blaster

    I know there is a power up capture, but I want to retrieve data after an other trigger condition was met.

    Is it possible ?

    notes :

    (1) : Does SignalTap work alone in FPGA = without having to press "Run analysis" ?

    (2) : Is there an risk of loosing FPGA configuration when pluggin USB Blaster ?

    Cordially.

    --- Quote End ---

    Why can't you do it in the usual order?

    1. Plug in USB BLASTER

    2. Launch Quartus > SignalTap program the FPGA with SignalTap

    3. Let the board function and capture data when it triggers.

    4. Download data.
  • Altera_Forum's avatar
    Altera_Forum
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    10 years ago

    I try to find a cause of a disfunction that stops a system : it occures at 1 min or lots of days after power-on.

    Because JTAG can reconfigure FPGA, I prefer NOT plugging USB Blaster when the board is functionning. The risk is too important.

    I made a "datalogger" board but it captures onl a few signals wich are not significant enough.

    So I would like to offload data from Signaltap AFTER triggered (and after securizing the system).
  • Altera_Forum's avatar
    Altera_Forum
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    10 years ago

    I think you would need USB blaster connected for the SignalTap to run. I believe the data is real time streamed into the PC which are connected to the board.

  • Altera_Forum's avatar
    Altera_Forum
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    10 years ago

    Why not just leave the USB-Blaster plugged into the board? That way the USB-Blaster is not "hot-plugged" into the JTAG header while your board is powered.

    You could leave the USB-Blaster plugged into a PC, so that the cable electronics is also powered, but that is not required. You could just plug the USB-Blaster USB connector into your PC after the board has been powered.

    SignalTap II has a power-on trigger configuration. This allows the FPGA instance of SignalTap II to trigger, and then you can retrieve the trace at a later time. I have used this to capture an event that would only occur every few days.

    Cheers,

    Dave
  • Altera_Forum's avatar
    Altera_Forum
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    10 years ago

    Because JTAG can set the FPGA into a high impedance which is catastrophic in my system, I can't allow that.

    --- Quote Start ---

    You could just plug the USB-Blaster USB connector into your PC after the board has been powered.

    --- Quote End ---

    NOT sure. I had burnt USB Blasters this way, I think.
  • Altera_Forum's avatar
    Altera_Forum
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    10 years ago

    --- Quote Start ---

    Because JTAG can set the FPGA into a high impedance which is catastrophic in my system, I can't allow that.

    --- Quote End ---

    Only if the TAP machine is programmed to issue the HIGHZ command. Its unlikely to randomly issue this command.

    --- Quote Start ---

    I had burnt USB Blasters this way, I think.

    --- Quote End ---

    It should work fine. The VCC_OUT voltage from the 10-pin header goes to dual-voltage buffers that are tolerant of either supply powered before the other.

    Cheers,

    Dave