Zynq 7000 External Mux

[Sam Bergami]

Hi I am trying to use the Zedboard zynq 7000 external mux and I was wondering if anyone could provide me with some detailed information or an overview of what exactly the purpose is of the external mux and how it functions.

Thanks

[jpeyron]

HI @Sam Bergami,

Could you be more specific with what you are trying to do. I'm not quite sure what you are talking about with the external mux. The only thing i could find was about using an external mux with the ADC like in this xilinx forum here.

thank you,

Jon

[Sam Bergami]

@jpeyron yes using the external mux with the ADC

[D@n]

@Sam Bergami,

Have you wired the Arduino 4051 to your board?  And if not that chip, is there another chip you've wired up?  If so, which one?

Dan

[Sam Bergami]

@D@n

We are using the Zynq 7000 Zedboard

[D@n]

@Sam Bergami,

Well that's a start ... but does the ZedBoard have an external mux?

Looking through the schematic, I'm only finding two things that might refer to what you are asking about.  The first is an audio port that will multiplex between microphone and line in.  The second is the XADC port that leads to an internal mux (not external).

So, like @jpeyron, I'm not certain what you are talking about yet.

Dan

[Sam Bergami]

If I want to just input a voltage using the XADC header pins and read something out in the terminal, how would I go about doing this? Is anyone familiar with the XADC Header pin outs?

I found this link to be helpful with specifying each pin, but I'm not sure what pins are needed to connect to what. I currently have the XADC header connected to a protoboard that has an output of 0.625 Volts. I am trying to connect the power from the protoboard to the XADC header pins so that I can read a signal other than 0 in the channels in the terminal, but I am still only getting 0.

Should I be connecting the power to both the Vp and Vn and then ground to pin 4 (AGND)? Do I need to have all of the grounds within the XADC header connected to ground?

[D@n]

@Sam Bergami,

Not having a Zedboard, but at least now understanding what you wish to do, I'll punt back to @jpeyron to see if he knows of an example for you to examine.

Until he gets back to you, you might wish to look at the XADC component library description in the 7-series libraries guide, or the guide for how to use the XADC in general.  There may be a different interface when using an O/S, but .... I'll wait to see what others have to say.

Dan

[Notarobot]

@Sam Bergami

Ealier this year it was a discussion about external XADC use on this forum. Although it was for Zybo board it is still relevant.

You will need external mux only if you want to get more channels than available in the XADC that is two.

Good luck!

 

[jpeyron]

HI @Sam Bergami,

Here is a thread that gives a different option than an external mux for using the other channels. Here is a good tutorial for the XADC I got from this Avnet forum thread here. Let me know if there is anything else I can help you with.

cheers,

Jon