LAN.PNG (273.57 KiB) Viewed 2 times
<span class="colour" style="color: rgb(68, 68, 68);">Hi,</span><br>
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<span class="colour" style="color: rgb(68, 68, 68);">I have designed and assembled a board that uses LAN8720A and ESP32 to create a POE setup. I broke it up into 3 sections for testing and verification; uC w/PHY, POE PD Controller.</span><br>
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<span class="colour" style="color: rgb(68, 68, 68);">But i test without POE in this case I'm currently only testing the uC/PHY isolated from everything else and providing power through USB dropping down to 3.3 using a linear reg. !!</span><br>
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<span class="colour" style="color: rgb(68, 68, 68);">The LAN8720A has communication with the esp32 but not with the network. i.e. the phy is configured without error and even detects when the LAN cable is connected and disconnected but it never gets an IP address and/or connect to MQTT server !!</span><br>
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<span class="colour" style="color: rgb(68, 68, 68);">I have a waveshare breakout board for the LAN8720A for which I followed sautter's guide and it works well. </span>[https://sautter.com/blog/ethernet-on-es ... ng-lan8720](https://sautter.com/blog/ethernet-on-esp32-using-lan8720)<br>
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<span class="colour" style="color: rgb(68, 68, 68);">I used the waveshare schematic as my starting point </span>[https://www.waveshare.com/w/upload/0/08 ... ematic.pdf](https://www.waveshare.com/w/upload/0/08/LAN8720-ETH-Board-Schematic.pdf)<br>
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<span class="colour" style="color: rgb(68, 68, 68);">When I compare schematics I don't see anything glaring that would seem to indicate improper connection so my guess is my issue is with layout.</span><br>
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<span class="colour" style="color: rgb(68, 68, 68);">i use transformers inside an RJ45 jack : </span>[https://docs.rs-online.com/90ab/0900766b815b818d.pdf](https://docs.rs-online.com/90ab/0900766b815b818d.pdf)<br>
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<span class="colour" style="color: rgb(68, 68, 68);">i have 4 layer pcb stackup 1.6mm (signal-GND-POWER-SIGNAL) with Impedance checked construction with EasyEDA : impedence diff 100R :</span><br>
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<span class="colour" style="color: rgb(68, 68, 68);">-track space 4.70 mil</span>
<span class="colour" style="color: rgb(68, 68, 68);">-track with 6.00 mil</span>
<span class="colour" style="color: rgb(68, 68, 68);">-track height 1.36 mil</span>
<span class="colour" style="color: rgb(68, 68, 68);">-isolation heigth 7.08 mil</span>
<span class="colour" style="color: rgb(68, 68, 68);">-dielectic cst FR4 4.300</span><br>
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<span class="colour" style="color: rgb(68, 68, 68);">Let me know if you see anything in the schematic or layout that might an issue.</span><br>
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<span class="colour" style="color: rgb(68, 68, 68);">Patiently waiting for your input.</span><br>
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<span class="colour" style="color: rgb(68, 68, 68);">Thanks!</span>
