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Altera_Forum's avatar
Altera_Forum
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12 years ago

What kind of JTAG this board is using?

Hello,

I'm following a tutorial PCB board for Cyclone 4. I'm using the design found here provided by one man has done it before:

https://bitbucket.org/avakar/omicron_analyzer/src/00e2960f9d152624229e0416a5fe175a9a5cb757/board?at=default

In his board, he seems to use a 6 pin-JTAG with these pins (attached in the image):

GND

VCCA1 (2.5V)

TDI

TCK

TMS

TDO

Im not so sure what kind of JTAG he is using. Would you please giving some suggestions? Any links to the actual products would be great. Thanks for the help

5 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    12 years ago

    AFAIK there isn't a JTAG connector pin-out standard. Although the 10-pin configuration used by Altera on the USB Blaster is quite common among different manufacturers, I've also seen some 6 pin variations. You should be able to use it with a USB blaster but you will need to make an adapter cable to connect the different signals to the correct pins.

  • Altera_Forum's avatar
    Altera_Forum
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    12 years ago

    --- Quote Start ---

    AFAIK there isn't a JTAG connector pin-out standard. Although the 10-pin configuration used by Altera on the USB Blaster is quite common among different manufacturers, I've also seen some 6 pin variations. You should be able to use it with a USB blaster but you will need to make an adapter cable to connect the different signals to the correct pins.

    --- Quote End ---

    Dear Daixiwen, by conencting "the different signals to the correct pins", you mean I just connect the pin from his JTAG port to the correct pin of the USB blaster, right?
  • Altera_Forum's avatar
    Altera_Forum
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    12 years ago

    Yes. You should find the pinout of the USB blaster 10-pin connector in the USB blaster user manual.

  • Altera_Forum's avatar
    Altera_Forum
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    12 years ago

    --- Quote Start ---

    Yes. You should find the pinout of the USB blaster 10-pin connector in the USB blaster user manual.

    --- Quote End ---

    Thanks Daixiwen. Only one more doubt. It's good that he connected the pins to 2.5V instead of 3.3V , but he didnt connect them to any pull up or pull down resistors. Is that safe to do so?
  • Altera_Forum's avatar
    Altera_Forum
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    12 years ago

    Cyclone IV has on-chip weak pull-up and pull-down resistors. They can be probably considered sufficient for unconnected JTAG pins. With PCB fan-out, the high impedance pins are prone to inteference pick-up. To be on the safe side, you should provide the suggested 1k resistors.