Pull 3.3V control signal from PMOD port

[Angie]

Hi, 

we are using AVNET ZedBoard and we would like to pull out a control signal from our Pmod port. Now the voltage can only reach 2.5V from Jc and Jd port, and reach 0.75V from Ja and Jb port. However, we need a voltage greater than 3V to drive our add-on mux. Is that possible for a PMOD to reach 3V on the ZedBoard?

Thank you very much. 

Angie

[jpeyron]

Hi @Angie,

How are you testing the voltage on the Pmod Ports? Are you using a constraint file and actively toggling a pin on the Pmod ports when you are testing the voltage? Looking at the schematic back 13 is set to 3.3v. Bank 13 is where the Pmod port JA,JB,JC and JD are connected. Here is the XDC for the zedboard.

cheers,

Jon

[Angie]

Hi, thanks for your reply. 

I put some hardware diagram on the ZedBoard and I test the PMOD voltage by pulling out the signal to a scope. I get around 0.7V output voltage from Ja and Jb port, and I get 2.5V voltage from Jc and Jd port. I have totally no idea why the voltage will drop under this circumstances. It would be very appreciated if somebody can help me to figure it out. 

Thanks again. 

Angie 

[jpeyron]

Hi @Angie,

I made a basic gpio single toggling output pin project for the Zedboard here using the xdc from here. I tested JA1, JB1, JC1P and JD1P for voltage output. All of the pins gave 3.3V when the signal is high. I have attached a screen shot of the voltage at the JA1 pin.I have also attached the sdk code as well. Please try the linked project and let us know what voltages you get.

cheers,

Jon 

main.c