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Altera_Forum's avatar
Altera_Forum
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16 years ago

Weird voltage level

Hi,

I have a EPM240 connected to my microcontroller. When I set my microcontroller pins as output to EPM240, the voltage level is only 0.6V. But, if I lift the pin of EPM240, my microcontroller output pin voltage turns to 3V (Supposingly, it should be 3V)

Is there any setting in Quartus II that I missed there?

Thank you!

2 Replies

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

    There must be something in the CPLD (either config settings or code) that is pulling the pin to ground. Make sure you've got your pin assignments correct and the pin is called out as an input.

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

    It is indicating that the line is shorted or something. This could happen if you set your unused pin to "output driving ground". This setting can be changed in Quartus II at "Assignments>Device>Device and Pin Options>Unused Pins".