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Altera_Forum's avatar
Altera_Forum
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12 years ago

max v jtag resistors

I followed the app note for jtag with Max 7000S and it works perfect. I'm switching over to 5M40ZE64C5N, are the 10k and 1k resistor still required?

Also I'm switching from 5v with Max 7000S to 1.8v only for Max V, will there be any issue with JTAG ISP? I'm using USB Blaster.

thanks!

1 Reply

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    12 years ago

    ok found the answer:

    For MAX V devices, there are weak pull-up resistors for

    TDI

    and

    TMS

    , and pull-down

    resistors for

    TCK

    . However, in a JTAG chain, there might be some devices that do not

    have internal pull-up or pull-down resistors. In this case, Altera recommends pulling

    the

    TMS

    pin high (through an external 10-k

    

    resistor), and pulling

    TCK

    low (through an

    external 1-k

    

    resistor) during BST or in-system programmability (ISP) to prevent the

    TAP controller from going into an unintended state. Pulling-up the

    TDI

    signal

    externally for the MAX V device is optional.