lign17314 / pynqsdr Goto Github PK

PYNQ-Z1 + AD936X SDR platform. Openwifi & PlutoSDR capable.

KiCad files | [Design notes TBD] | [Blog TBD]

Documents/blogs coming soon, stay tuned!

This project demonstrated that AD936X chip can combine with low-cost ZYNQ FPGA development boards, especially PYNQ-Z1, and run openwifi without problem. This can potentially become an extremely low-cost openwifi platform. And with extensions removed, you still have a working(maybe except HDMI) PYNQ capable of any other serious ZYNQ projects.

Of course, a series of "hacking" is required:

• AD936X run on 1.8 V or 2.5 V, while most FPGA boards have VCCIO 3.3 V
  • Use level converters like SN74AX8T245. Changing VCCIO is not plausible because USB and ETH PHY need 3.3 V
• Wiring is both poor and long on FPGA boards
  • So have to use LVDS mode
• But ZYNQ with 3.3 V HP VCCIO can't run LVDS
  • For receiving, VCCIO 3.3 V bank can use LVDS_25 constraint, as long as external termination is used
    • So change HDMI 50 ohm pull-up resistors to 100 ohm LVDS termination
  • For sending, I use single-ended output on FPGA, and convert these to LVDS using DS90LVDS047
• PMOD may can't run high speed
  • Remove TVS diodes and 200 ohm series resistors, can run at 120 MHz
• Board shape is strange...
  • Small connectors on PMOD/HDMI side is required
• Hand-solder BGA?
  • Heatgun, soldering iron, solder paste, flux are enough, it's really not that hard

Detailed modification of PYNQ-Z1 coming soon.

Current version requires modification of the PYNQ-Z1 board aka 0402 soldering. I'll try if I can get this working with zero modification on PYNQ side. If coming tests show positive result, there'll be a version 2.

Openwifi running on PYNQSDR:

Board anatomy:

Openwifi: https://github.com/open-sdr/openwifi

PlutoSDR: https://github.com/analogdevicesinc/plutosdr-fw

RF frontend PCB design based on https://github.com/kangyuzhe666/ZYNQ7010-7020_AD9363

Many online discussion groups also gave me a lot of help.

GPLv3 for all board files. CC BY-SA for blog articles, documents, photos and the logo. Code are coming from different projects and should remain their original licenses.