Release

README.md

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+## PYNQSDR
+
+![](pic/logo.png)
+
+PYNQ-Z1 + AD936X SDR platform. Openwifi & PlutoSDR capable. 
+
+**Hardware files/documents/blogs coming soon, stay tuned!**
+
+#### Design
+
+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. 
+
+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.*
+
+#### Gallery
+
+Openwifi running on PYNQSDR: 
+
+![](pic/openwifi_running.png)
+
+Board anatomy: 
+
+![](pic/anatomy.png)
+
+#### Credits
+
+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. 
+
+#### License
+
+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.