SoC Zynq Development Board Review

[Alfgan]

Hello Everyone!

I want to show you and ask for a review for my new designed SoC Zynq Development Board. This board has been designed during Phils Lab "Advanced Digital Hardware Design" course.

Board features:

• AMD/Xilinx Zync System on Chip (SoC) Half APU (Application Processing Unit) and half FPGA
• 1GB DDR3 Memory
• 4GB eMMC Memory
• Gigabit Ethernet
• USB HS OTG (USB High Speed On-the-Go) enables connectivity between portable consumer electronic devices over the industry's most popular peripheral interface
• On-Board USB-to-JTAG
• Embedded Linux-Capable

In comparison to the original course project component selection, schematics and critical component placement this project is almost identical to the course project, however symbol library, footprint library and schematics have been done by myself in my style and all supportive components placements and layout have been done by myself in trial and error style . It took me long hours to design this board.

I have not chosen to design my own unique project, because my hobby projects are typically much cheaper and not so advanced in layout perspective, and this board together with assembly and components are out of my hobby budget. Still, during the course and design of this project I learned a lot of new stuff and boosted my skills in HW and PCB design for both hobby and work. Although, I will not be ordering this project and wanted so share it for a review because is taken a lot of hours to complete it and maybe some of you will give me feedback with recommendations how it could be improved or take something for themselves

These are a link for Schematics, BoM, Assembly Notes, Fabrication Notes and Gerbers:

https://www.dropbox.com/scl/fi/e26ksmoyc0de6dk00eiw2/Sapphire-23.zip?rlkey=ttwp1lo13y5qj7gvg93ofshs3&dl=0

Thanks and wish everyone a good day!

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[Alfgan]

Thre is the layout

[moffy]

Congrats on what is a very neat looking board, which must have taken many hours to design and layout. Have you built and tested one yet? And what is your intended development software toolchain and programming debugging? Is that all accessible via USB and the Xilinix software tools?

[coromonadalix]

seems well done

some  comments
-  i would have turned 180 degree one of the mezzanine connector,  to be sure if you rotate your board it will not slot in them


will be a thick board .... we use theses Zynq series up to the biggest model with an heatsink,  Peta Linux in them, boot thru sd-card and we put them in flash mode

-  maybe the dip switches should have been put on top ??
-  and for sure you don't provide any buffer / protection on the mezzanine pins,   one of our  Zynq got damaged, and we had to check all gpios until we found out one pin in the Zynq was toasted  ??


4gb for emmc storage seems a little short, you don't do  logging by any chance ?  depends on how you'll optimize your "OS"


you have some boards like this project :   https://www.myirtech.com
not affiliated

[Alfgan]

@moffy I have not built it yet the board are quire expensive and a bit out of my hobby budget right now
The toolchain is Xillinx Vivado.
Access to the board is via USB and FTDI and use JTAG via Digilent JTAG-USB Cable
https://lt.farnell.com/digilent/250-003/programming-cable-jtag-to-usb/dp/2061852

@coromonadalix Thanks for review!
- Good note about mezzanine connector
- Yea, Dip switch could be changed with Termination Power Supply that way it would be accessible from the TOP
- Good idea to add protection for mezzanine connectors
- I was thinking that  4GB would be more than enough, most of my designs have MCUs with <500kB

I am pretty new for such complexity designs, so, study, design and show design for review and feedback the study more. Or study, build, fail and study again

[mr_byte31]

possible to put the project on Github ?

[nctnico]

Late to the game: I'm missing TVS diodes on the ethernet lines to the phy. And for good measure: put zero-Ohm resistors in the lines between the phy and the connector. If you fail EMC, you can add some series resistance or inductance (ferrite) bead and save the day without a respin.

I also notice you have a seperate circuit and chassis ground which meet at the ethernet connector. Don't do that. You'll fail EMC testing for radiated emissions for sure. Have one and only one ground!

I'm also missing filtering on the power plug. Better put something like a common-mode choke in series with the power plug. I also don't like the use of polarity protection diodes. Personally I like to use a big fat unidirection TVS which offer both overvoltage and reverse polarity protection. Bonus points when adding a  PTC fuse.

[coromonadalix]

ill go against nctnico,  i love the diode in serie,  he do use an efuse circuit , wich i find practical

wrong polarity = nothing powers up,  no shorted out tvs diode or something,  wich could impede the pcb

i do understand  tvs  etc ... but hell  when they short out, if they do,  you loose the pcb until it's repaired,   an ptc fuse will open and close open again if its placed before the tvs / protection,  it will create power spikes / surges

been there done that.  i would personally keep the diode idea,  some efuse if they sense wrong polarity they simply opens up,  nothing powered up on the output = safe