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Altera_Forum's avatar
Altera_Forum
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15 years ago

High analog input for DE1

Hi

Doe's anybody knows how can analog signal that is higher than 3.3V be connected to the FPGA input? (without additional HW beside the DE1).

Thanks

Eyal

3 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    DE1 has no analog inputs except the audio codec's line and mic in. So you most likely need external ADC circuitry (or at least a comparator). What do you want to achieve?

  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    Hi

    There is a technic to perform ADC on FPGA (Sigma Delta converter) but I need something else.

    I need to receive digital input of 5V or higher (digital signals from various boards). I don't need analog input (sorry for misleading).

    Do you know if it possible to inject 5V to the FPGA input?

    Eyal
  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    DE1 has no input protection on GPIO inputs, only 47 ohm series resistors. Depending on the speed requirements, you can use level translator ICs or voltage dividers for the input signals to FPGA.