Sam Bergami Posted June 19, 2017 Share Posted June 19, 2017 Is there a way to just input a voltage and read it through the terminal using the XADC Header on the Zynq 7000 Zedboard? If so can this be done using the VP VN pins? Link to comment Share on other sites More sharing options...
jpeyron Posted June 20, 2017 Share Posted June 20, 2017 Hi @Sam Bergami, I am still working on this issue. I did want to ask what REV of the Zedboad do you have? cheers, Jon Link to comment Share on other sites More sharing options...
Sam Bergami Posted June 21, 2017 Author Share Posted June 21, 2017 @jpeyron I think it's REV D Link to comment Share on other sites More sharing options...
jpeyron Posted June 21, 2017 Share Posted June 21, 2017 Hi @Sam Bergami, I am still working on this issue and am currently unable to get any value change from external voltage on the XADC for Vaux0 and Vaux8. I have reached out to more experienced engineers for some input on this issue. While I are working through this issue I also wanted to ask if you had also reached out to Zedboard.org (here). They may have had a similar question and have a potential solution for you. thank you, Jon Link to comment Share on other sites More sharing options...
Sam Bergami Posted June 22, 2017 Author Share Posted June 22, 2017 @jpeyron Yes I just posted on the Avnet forums again. Link to comment Share on other sites More sharing options...
Sam Bergami Posted June 22, 2017 Author Share Posted June 22, 2017 @jpeyron Avnet referred me back over here. They can't help. Link to comment Share on other sites More sharing options...
jpeyron Posted June 23, 2017 Share Posted June 23, 2017 Hi @Sam Bergami, I was able to get a voltage on Vaux8 using the project attached below. The thing I was initially missing was that the xadc header position is oriented differently than I thought which caused some issues. If you look above the xadc header on the right you will see a 1. This is where Vn is. If you look at the xdac header with 1 at the top left the the schematic here will reflect where the pins are. These pins are deferentially paired and you will get the difference between Vaux8p and Vaux8n. I had agnd and Vref connected to ground and i gave Vaux8p 500mV and Vaux8n 50mV and i got roughly 450mV shown in tera term for Vaux8. I believe this header was made to work with the xilinx daughter board here. zedboard_xadc.zip Link to comment Share on other sites More sharing options...
jpeyron Posted July 5, 2017 Share Posted July 5, 2017 Hi @Sam Bergami, I am not sure why your voltage is jumping. Have you checked your voltage source? also remember that the xadx averaging is set at 16. I just went through the project again and my voltage is not changing. I have attached screen shots. and a picture of my wiring. I have attached the three grounds as well as Vaux8p and Vaux8n. 20170705_160436.zip Link to comment Share on other sites More sharing options...
Sam Bergami Posted June 27, 2017 Author Share Posted June 27, 2017 @jpeyron Also does it matter which project we download and use or are they the same (meaning the one from your first post compared to the one in your newest post)? Link to comment Share on other sites More sharing options...
jpeyron Posted June 27, 2017 Share Posted June 27, 2017 Hi @Sam Bergami, In your picture you have them attached incorrectly. They are connected to the following pins on the XADC Header: blue - Vaux0n, yellow - Vaux8n, green - DXP white -AGND grey - DXN Black - 5v0 On the screen shots I have attached and added the number 1 to reflect what is on the board and the orientation of the IC . I also attached a picture of the orientation you should be looking at the board to match the attached screen shots. Sorry the projects are the same. I did not see the project attached on my first post so I re-attached it. 20170627_125405.zip Link to comment Share on other sites More sharing options...
Sam Bergami Posted June 28, 2017 Author Share Posted June 28, 2017 @jpeyron We got it to work! We were off by one pin for each. I'm attaching a picture of our terminal readings. We are inputting about 0.75 volts into Vaux8P and about 0.50 volts into vaux8n. We are unsure as to why the voltage jumps every other reading. Any ideas? Thanks so much for your help! Link to comment Share on other sites More sharing options...
gutielo Posted June 29, 2017 Share Posted June 29, 2017 Hello! I see you got it working @Sam Bergami and I would like to know if you only needed to connect the pins you mentioned here. What about the analog 1.8V supply? (VCCADC, which is pin number 14) Also, I thought the pin number 11 (Vref) was an output pin that provided a reference of 1.25V from the board, so you're not supposed to connect it to GND or am I wrong? Thanks in advance! Link to comment Share on other sites More sharing options...
Sam Bergami Posted June 30, 2017 Author Share Posted June 30, 2017 Hi @gutielo The connections in my above picture are actually incorrect. But you want to connect two different Voltages to the Vaux8 pins. I used 0.75V for Vaux8P and 0.50V for Vaux8N. Then I connected the three AGNDs and Vref to ground. If you used the two diagrams above that jpeyron posted you can see the correct order of the pins. When looking at the Zedboard head on, the top right pin on the xadc header is Vn. As far as Vref goes I'm not sure. I haven't tried running the program without connecting Vref to ground, so I'm not sure how it will work out. Perhaps @jpeyron can answer your Vref question? Link to comment Share on other sites More sharing options...
gutielo Posted June 30, 2017 Share Posted June 30, 2017 Thanks for the heads up about the incorrect picture, @Sam Bergami As soon as I can, I'll try to run some tests and I'll let you know if Vref can be left unconnected. But as you say, if @jpeyron can enlighten us, I'd appreciate that! So you're not feeding it with 1.8V? That's something I'm surprised at. Link to comment Share on other sites More sharing options...
jpeyron Posted June 30, 2017 Share Posted June 30, 2017 Hi @gutielo and @Sam Bergami, Looking at table 17 on page 26 of the reference manual here Vref is the 1.25V reference from the board So you do not need this Pin. When I was running the project I ended up only using one of the agnd and the Vaux8p and Vaux8n. cheers, Jon Link to comment Share on other sites More sharing options...
gutielo Posted July 1, 2017 Share Posted July 1, 2017 I'll try using only one of the AGND and VAUX8(P/N) then, and see if I can get it working, that should be good to start! Thanks for your help. I have one last question, what frequency is the clock you're feeding the XADC with? I'm using the one provided by Xillybus (100 MHz), but I've read it shouldn't be higher than 26 MHz (I don't really think this is true, but just to make sure...) Link to comment Share on other sites More sharing options...
Sam Bergami Posted July 3, 2017 Author Share Posted July 3, 2017 On 6/28/2017 at 8:46 AM, Sam Bergami said: @jpeyron We got it to work! We were off by one pin for each. I'm attaching a picture of our terminal readings. We are inputting about 0.75 volts into Vaux8P and about 0.50 volts into vaux8n. We are unsure as to why the voltage jumps every other reading. Any ideas? Thanks so much for your help! @jpeyron Any ideas as to why this is happening in my terminal? Link to comment Share on other sites More sharing options...
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Sam Bergami
Is there a way to just input a voltage and read it through the terminal using the XADC Header on the Zynq 7000 Zedboard? If so can this be done using the VP VN pins?
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