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Altera_Forum's avatar
Altera_Forum
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14 years ago

LVDS pins next to a 2.5 volt pins

Greeting, I am getting an error telling me I cannot put an LVDS pin next to a 2.5 volt pin that will be responsible for and fault LED blinking. Is there any way to get around this or is there a way to temporarly disable the LVDS pins to trouble shoot the design and fix it in the next spin?

Thanks as always

GE_bill

4 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    If you come to conclusion that the single ended output won't disturb LVDS operation, e.g because it's not switching at times when the LVDS is active, you can assign a toggle rate of "0 MHz" to the pin, and it's ignored in pin placement rule check. A reasonable example is e.g. a configuration EEPROM of a DDRRAM module, that's read in before RAM operation starts.

  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    If you do not need to drive the LVDS signal during trouble shoting you can always reconfigure the LVDS pins to normal single ended inputs.

    It is recomended to allways run the pin placement through the QuartusII tools before setting the PCB. There are many constraints on which pin a signal can be placed on.

    /Henrik