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Altera_Forum's avatar
Altera_Forum
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16 years ago

Arbitrary VCCIO

Hi,

I want to use a Cyclone II device to drive some low power logic. That logic require inputs around 200mv (as logic 1).

Is it possible to set the Cyclone's VCCIO that low, and will it give me the correct output?

2 Replies

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

    Thank for the idea.

    I guess i'll need several high precision resisters.

    An other question related: can i change the VCCIO when the system is powered on? In my current project i have a variable supply connected to VCCIO and changing it's voltage changed the output. However, I'm not sure if this is good for the Altera device.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    Rather unlikely, but you may want to try. A resistive divider with e.g. 50 ohm output impedance would generate the 200 mV level perfectly, however.