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Altera_Forum's avatar
Altera_Forum
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15 years ago

Help! --“msel” floating in cyclone ii design..

I know msel0 and msel1 should be connected to VCC or GND.

but I forgot to connect them.

when I debug the PCB,the cyclone ii device become very hot quickly!

:(

can it because of the "msel problem"?

:all VCCIO = 3.3,VCCINT = 1.2.

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    The Cyclone II datasheet is very clear about the need for connecting MSEL pins. In so far, a service request surely won't get the answer ist's O.K. It's different e.g. with Cyclone III, that has pull-down resistors for MSEL.

    I would also rather expect I/O shorts to cause excessive power dissipation. But I can't exclude, that the problem may be caused by unconnected MSEL.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    15 years ago

    Hi,

    Is it a custom board ?

    Msel problems ? I don't know. You can make a "service request" on Altera web site.

    the cyclone ii device become very hot quickly if there are short-circuits with your board.

    Have you configured unused pins as "input tri-stated" ?

    By defaut, it is "output driving GND" which is a bad ideea in my opinion.