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Altera_Forum's avatar
Altera_Forum
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16 years ago

DE2 EP2C35 and Output GPIO Voltage

I'm using the Altera Cyclone II DE2 EP2C35 board. The goal is to use it to drive the INIT signal to a sonar sensor. However our output pin isn't giving us the voltage we need to trigger the sensor.

With the terrasic DE2-70 (not the EP2C35) you can use a jumper to modify the voltage supplied by the output pins between 1.5(~) or 3.3V.

Is there a way to achieve the same affect with this board? When I use a switch to drive an output pin we're seeing ~32mV for logical 0 and ~1.12V for logical 1 from a volt-meter. I'm putting the volt-meter across the GND supplied to pin 12 and pin 1 of JP1. This should be the output pin GPIO_0[0] and GND.

I've read here:

http://www.altera.com/literature/hb/cyc2/cyc2_cii5v1_04.pdf

under "5.0-V Device Compatibility"

that if you connect 3.3V to the VCCIO pins you can get 3.3V to your output pins. I've scoured the documentation, but I have no idea how to do this.

Please help! The 1st half presentation with our project is due on the 7th

1 Reply

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

    DE2 is using a VCCIO of 3.3V for all IO banks as you can see from the board schematics. You either terminated the pin with around 50 ohm, which isn't suitable if you need 3V signal level, or the board has been damaged. You may want to check the unloaded output level first.