wESP32: Wired ESP32 with Ethernet and PoE

A low cost ESP32 core board with Ethernet and PoE for convenient "single cable" deployments

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The ESP32 is very popular among makers as the brains for various projects. Usually it is connected to the internet with WiFi, but an often overlooked feature of the ESP32 is that it also contains an Ethernet MAC. This project aims to create a hacker friendly ESP32 + Ethernet + PoE core board to make it very easy to apply the power of the ESP32 in new areas such as home automation, factory automation, smart buildings and data centers, where the use PoE provides major advantages in installation and maintenance.

Due to the high power consumption of WiFi, most ESP32 based systems already require wired power. Since you already need a wire, why not provide power and connectivity through a single wire and bypass deployment hassles associated with WiFi credentials and RF performance in hard-to-reach locations?

Plus the high power available with PoE makes it possible to not only make ESP32 based sensor nodes, but to create smart network-connected actuators as well!

I just completed an application-specific ESP32 based PoE board for a customer, and it got me thinking: how much interest would there be in a generic ESP32 PoE core board?

By using PoE, a single cable provides power as well as connectivity, easing deployment headaches for large installations.  PoE can provide up to 12.95 W to a load while PoE+ specifies up to 25.50 W.  Plenty for an ESP32 which takes only a watt or so, making it possible to power other loads.  PoE capable network switches and injectors are also becoming quite common and have come down in price as well.

The nice thing about the ESP32 is that it's low cost and powerful, and provides WiFi and Bluetooth in addition to Ethernet.  So even if a deployment would be mostly Ethernet and PoE based, it would still be possible to connect a node with WiFi powered from another source if necessary.  Or it could be set up as an access point for other WiFi or Bluetooth LE based sensors.

While it would be nice to support as much power as possible, previous experience has taught me that high power opens all sorts of cans of worms related to heat dissipation and EMI.  So it seems prudent to not start at the highest power levels possible.  Some potential users also showed interest in compact, very low power systems, but there are plenty who were excited about the idea of having a decent amount of power available.  So I decided to take the middle road and do a 12.95W PoE class 3 design to start with.

The ability to use local power instead of PoE is a nice feature, but also adds complexity and cost.  The problem is that PoE uses 48V nominal to reduce wiring losses, but commonly available wall warts use lower voltages for safety.  Supporting both would require the circuit to support for a wide input voltage range making things more complex.

So I settled for the following solutions: local power can provided either by adding a PoE injector, or through the (optional) USB port.  Of course, from the USB port, only 5V will be available.

Talking about the USB port, several potential users expressed the opinion to not burden every board with something that would likely only be used during once during programming and never again after that.  I agree, so I made the USB programming/terminal port an optional module.

Other than those concerns, I want this module to be fully isolated (to prevent issues with long cabling), full featured (Ethernet, WiFi, Bluetooth LE, many ESP32 pins exposed), low cost and small.


Mechanical drawing of the wESP32 rev 3

Adobe Portable Document Format - 88.38 kB - 01/07/2020 at 16:37


Eagle CAD source files of the wESP32-Prog programming submodule

Zip Archive - 50.43 kB - 10/07/2019 at 14:41



Schematic of wESP32-Prog programming submodule

Adobe Portable Document Format - 19.49 kB - 10/07/2019 at 14:41



Schematic of wESP32 rev 3 with PMS150C to manage PHY reset

Adobe Portable Document Format - 43.55 kB - 03/19/2019 at 23:10



Complete schematic of wESP32 core module

Adobe Portable Document Format - 45.40 kB - 04/20/2018 at 18:30


View all 10 files

  • Second production run

    Patrick Van Oosterwijck05/10/2019 at 18:36 4 comments

    "Silicognition" PMS150C-559

    As mentioned in the last update, I ordered factory programmed Padauk PMS150C-U06 chips from Sino-Mos to provide a reliable reset for the PHY chip on every board.

    I expected everything to be OK with them, but you never know 100% for sure if everything was understood correctly when dealing with China, until you actually have something in-hand. For one thing, I was relieved that they had indeed re-reeled them. It would have been a big bummer if I would have received a bag of loose SOT-23’s. :)

    Then I had to make sure they were indeed programmed. So I reworked another 12 boards from the first batch that didn’t initialize the PHY correctly with chips from one of these reels, and after rework they all work flawlessly!

    Getting these chips has actually been a smoother experience than I had expected. It’s kind of cool to now have a low-cost custom chip that does exactly what I want it to do, with its own partnumber and everything. PMS150C-559 is now forever an “ESP32 Ethernet PHY reset manager”. Maybe I should write a datasheet for it. :)

    Also, since I have 9,000 of them, I can definitely spare some if anyone is making their own ESP32 board with Ethernet and wants a canned solution to deal with the LAN8720A PHY reset. There’s an updated schematic that shows how the chip is used on the new wESP32 revision. So get in touch if you want to buy some.

    Rev 3 PCBs

    I took a little risk and ordered new PCB panels that use the PMS150C-559 before I had verified the factory programmed chips. But it had all been taking much longer than expected already and some backers have been wondering when they’d receive their reward, so I tried to recoup some time that way.

    Having everything in-house I made a kit to send to a CM I was going to try in Mexico.  That's when things started to go really sideways.

    The scourge that is customs

    The first customs issue I ran into: how to do the paperwork correctly. This was going into Mexico temporarily just to have it assembled and then it was coming right back to the US. I sought advice from the CM and a local export company, and yes, I received information on some generalities, but no one really gave me any concrete answers on what codes to use, exemptions to claim or checkboxes to tick. So after wasting almost a week waiting for guidance I gave up and shipped the box with the documentation as good as I could figure it. I marked the shipment with the AES 30.37(q) to indicate a temporary export that would be returned within a year. Whether that is correct or not I don’t know. Nobody had told me what to do and it seemed the right thing to do.

    DHL got the box to Mexico after 4 days or so. Then the trouble started. First they claimed they couldn’t contact the CM at the telephone number I had been given and had put on the forms. They wouldn’t tell me why they needed to contact them. DHL was giving me options like “we can send your package back, or send it somewhere else for an extra charge, or we can destroy it for you (!)”. This nonsense took a week or so, a week of anxious freaking out for me. Then after wasting what they must have deemed sufficient time, they somehow did manage to get in touch with them and supposedly needed a tax ID from me. I run a passthrough LLC and certainly wasn’t going to give them my SSN! That sort of blew over after some work done by the CM and then they found that the contents of the box didn’t match the PI I had included. This was partially my fault: I had based the PI on the BOM, but even though neither me nor the CM cares about the exact part number of a reel of resistors, of course customs paper pushers do. I also had included some full and partial reels in the kit and amounts on the PI didn’t match. I really didn’t think anyone cared just how many parts were left on a partial reel, but of course they did.

    What a joke. None of it should have mattered of course. The parts are temporarily...

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  • The PHY reset saga

    Patrick Van Oosterwijck03/11/2019 at 16:09 2 comments

    Finally, a long overdue update! The silence doesn’t mean we’ve been taking it easy, on the contrary: we’ve been hard at work to make the wESP32 even better!

    A yield problem

    After the initial build of 245 units, we were able to ship 205 units that were good right away. There were various issues with the remaining 40, but the vast majority of them had the same problem: the Ethernet PHY would not get initialized properly.

    The LAN8720A Ethernet PHY is kind of a difficult part. It has several pins that have double use: during reset their logic level indicates various configuration settings, while after reset they are used in the RMII interface to communicate with the ESP32. An extra difficulty is that the chip expects the 50 MHz clock to be present during reset, so the chip can clock in these configuration settings.

    Unfortunately, the ESP32 by default uses the IO0 pin for the Ethernet MAC clock. (More options have become available for dealing with the Ethernet MAC and PHY clocks, but because IO0 was the first option available in the SDK, it enjoys the broadest firmware support so that’s why I keep using it. Plus to keep as many other ESP32 pins as possible available to the user!) The ESP32 IO0 pin is kind of a difficult pin as well, since it is used on reset to determine whether the ESP32 should go into programming mode or run the current firmware. So we have a perfect storm of an IO0 pin that needs to be high at boot to run normally, but low at boot to go into programming mode, and needs to have the 50 MHz clock on it after boot to allow Ethernet communication, and that before the PHY comes out of reset.

    When I designed the wESP32, I just looked at how Olimex dealt with the IO0, ESP32 reset and PHY reset on their ESP32-GATEWAY and copied that for the wESP32, figuring they must already have found a good solution since this was a product in production. On my first hand-built prototypes, it all worked well, so I went ahead with it in production. Then I found that more than 10% of the boards had an issue. Interestingly, in their latest revisions, Olimex has changed their product to use IO17 as PHY clock output to bypass the whole problem! This might be a smart thing to do, but I am loath to make backwards incompatible changes and take a precious GPIO pin away from the user. So I started looking at other ways to deal with this.

    Looking for a solution

    I needed a solution that would act as a reset manager for the 50 MHz oscillator and Ethernet PHY and would be triggered by the EN signal to the ESP32. When EN is low on power-up and when triggered by a programmer, the 50 MHz oscillator needs to be off, so the programmer can drive the IO0 pin low to enter programming mode, or the IO0 can stay pulled high and the system boots. The PHY needs to be kept in reset as well, because its reset can only be released after the 50 MHz clock has started up. After the ESP32 has had the opportunity to determine the boot state, the 50 MHz clock needs to be turned on, and only after the clock signal is present can the PHY reset be released.

    I had assumed there would be plenty of low cost, SOT packaged voltage detectors and reset managers that could replace my existing solution in the space I had available, but to my great surprise, nothing I could find in the market really seemed to fit the bill. There are plenty of supervisors that monitor multiple voltages and generate a reset, but I couldn’t find any low cost options that monitor one input and generate two reset signals with separate delays.

    So I started thinking outside the box: did I really need to add a little microcontroller to do this? There are several microcontrollers that are cheaper than higher end supervisor chips, and it would give me full flexibility to generate the reset signals exactly how I wanted them. On the other hand, I didn’t really want to deal with programming this micro on every board. I would need to add programming pads and a manufacturing...

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  • Don't blow up your Ethernet phy!

    Patrick Van Oosterwijck01/16/2019 at 16:29 0 comments

    You may have noticed a warning at the bottom of the MongooseOS demo in the demo code repo, about accidentally blowing up the Ethernet phy while playing with MongooseOS demo code.

    I didn’t find any time to pursue this further, but I have to give the people at MongooseOS credit for getting to the bottom of this! I received this message from them:

    We did some research, and found the problem with ethernet. It happened to be quite stupid: the default config for the built-in LED used pin 22, which conflicts with the ethernet TX.
    So, this command should set the board correctly:
    mos flash esp32
    mos config-set eth.enable=true eth.mdc_gpio=16 eth.mdio_gpio=17

    This highlights an issue that can happen with other firmwares as well: misconfigured pins doing damage to the phy. By default, the wESP32 ships with MicroPython installed and it is configured correctly out-of-the-box for the Ethernet phy as it is configured on the wESP32. If you load different firmware though, it is your responsibility to ensure the ESP32 pins are configured correctly and will for instance not configure an ESP32 pin as an output that connects to a phy output, and thus cause a short. Please refer to the schematic to make sure. The wESP32 website section on Software provides more information on wESP32 support in different environments.

    If you have ordered one or more wESP32's, I recommend you try it with the default MicroPython firmware when you first receive it, to confirm the hardware is sound and it receives an IP address (check with lan.ifconfig()) from DHCP over Ethernet, which only happens if the phy is working. All units are tested to do this before they are shipped, but this way you can prove to yourself the hardware is OK and nothing bad happened during shipping. After that you are free to use whatever firmware you want of course, but I will not replace defective units once they have been flashed with different firmware, as I cannot know what happened to them.  Thanks for understanding!

  • We are shipping

    Patrick Van Oosterwijck01/16/2019 at 16:24 0 comments

    On Monday 1/7, we finally received completed panels from Colorado Tech Shop!

    So we spent most of this week doing final assembly (installation of two through-hole electrolytic capacitors and the Ethernet jacks) and testing for all 245 boards in the first batch. I am quite pleased with the result, I hope you backers will be happy as well!

    Some boards were used for internal testing, some had to be sent back to Colorado Tech Shop for rework after finding issues during test, but today we were able to ship the first 205 units to Crowd Supply for delivery to backers next week.

    One of the boards was used for an experiment. I wanted to see if the board worked with the AI-Thinker ESP32-S module instead of the ESP32-WROOM-32:

    I’m happy to report it seems to work just the same, so this module could be used to provide a future U.FL antenna connector option!

  • Production update, and testers!

    Patrick Van Oosterwijck12/30/2018 at 06:39 0 comments

    Last week it dawned on me that time keeps passing and I hadn't given much thought yet to how I was going to test the wESP32 and wESP32-Prog boards before we ship them!  A very important issue to start cranking on, especially with holidays and vacation eating up a good amount of time.

    wESP32-Prog tester

    The wESP32-Prog board is quite simple and because of this, the tester can be simple as well.  Building the tester only took half a day and this is what I ended up with:

    The hardware consists of a little STM8S103F3 board that can be had for less than a dollar on AliExpress.  I had it laying around and all I needed for this was a simple UART capable chip, so this was perfect.  I used the Sduino project project to speed up firmware development.   It looks slightly different from normal Arduino code because the SDCC compiler doesn't support C++, only C.  It was simple enough to get it to work though, resulting in this code:

    // wESP32-Prog tester using STM8S103 board and sDuino
    #define IO0   PA1
    #define EN    PA2
    void setup() {
      // Initialize digital pin LED_BUILTIN as an output.
      pinMode(LED_BUILTIN, OUTPUT);
      digitalWrite(LED_BUILTIN, 1);
      // Initialize EN and IO0 test pins as input with pullup
      pinMode(IO0, INPUT_PULLUP);
      pinMode(EN, INPUT_PULLUP);
        // Init serial port to 115200 bps
    void loop() {
      // Read a byte from serial port
      int c = Serial_read();
      // Did we get a byte?
      if (c >= 0) {
        // Set lowest bit to value of IO0
        c = (c & 0xFE) | (digitalRead(IO0) ? 0x01 : 0);
        // Set second lowest bit to value of EN
        c = (c & 0xFD) | (digitalRead(EN) ? 0x02 : 0);
        // Echo byte back with altered IO0 and EN bits
        // Set the green LED state according to the second highest bit
        digitalWrite(LED_BUILTIN, (c & 0x40) ? 0 : 1);

     All this does is when a byte comes in, echo it back with the bottom two bits replaced by the current state of the IO0 and EN signals.  The second to highest bit also sets the tester board's on-board LED state.

    This firmware works in conjunction with a little Python script on my Linux box:

    #!/usr/bin/env python3
    import os
    import glob
    import serial
    import time
    from termcolor import colored
    while True:
      print("Waiting for wESP32-Prog...")
        ports = []
      while not ports:
        ports = glob.glob('/dev/ttyUSB*')
      print("Serial port detected, waiting for access...")
        while (not os.access(ports[0], os.R_OK|os.W_OK)):
        print("Testing wESP32-Prog...")
        test_ok = True
      s = serial.Serial(port=ports[0], baudrate=115200, timeout=0.1)
      res =
      if (res not in [b'0', b'1', b'2', b'3']):
        print(colored("ERROR: Serial data did not echo correctly, is the tester connected?", 'red'))
        test_ok = False
      if (res != b'3'):
        print(colored("ERROR: IO0 and/or EN pulled low when neither is asserted!", 'red'))
        test_ok = False
      if ( != b'1'):
        print(colored("ERROR: EN not pulled low correctly!", 'red'))
        test_ok = False
      if ( != b'3'):
        print(colored("ERROR: IO0 and/or EN pulled low when both are asserted!", 'red'))
        test_ok = False
      if ( != b'2'):
        print(colored("ERROR: IO0 not pulled low correctly!", 'red'))
        test_ok = False
      if (test_ok):
        print(colored("OK! All tests passed.", 'green'))
      print("Please unplug wESP32-Prog.")
        while ports:
        ports = glob.glob('/dev/ttyUSB*')

     What this does is wait for the wESP32-Prog board to be plugged in, which will create a /dev/ttyUSB0 device.  For some reason, trying to immediately open the serial device after this threw an access error, so we wait until it becomes accessible and then open it.

    Testing ensures that when we send a byte, the STM8 micro echoes a (modified) byte back to us.  We do this with various states of the RTS and DTR signals which control...

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  • Crowd Supply campaign ending!

    Patrick Van Oosterwijck11/12/2018 at 17:51 0 comments

    The Crowd Supply campaign has been going very well and will be ending soon, so if you haven't put in an order yet and you want one, now is the time! :)

    I've been putting quite a bit of work into the software side of things during the campaign, to make it as easy as possible for anyone wanting to design something with this to get started.

    First of all, there's now a web site at  It contains information on the hardware and on software development in different environments.  Most importantly, it contains a link to the Product Brief, which is pretty much the go-to for all detailed information.

    While the web site contains guidance on how to use the wESP32 with different development environments, there is now also a wESP32 demo code repository on Github, which contains full projects to get you started!  At the time of writing it has the iperf Ethernet IDF code I used to get the performance numbers mentioned in my project logs, an ESP32-Arduino example to control a display from a web server, two simple MicroPython examples to control an LED light, one from a web server and one using, and a Mongoose OS demo that allows you to control an LED light very simply from an automatically generated web app!

    If you take a look at these examples, you can see that most of them are quite simple and don't require much code at all.  For instance, here's the LED control from code:

    import machine
    import time
    import urequests
    # Initialize light PWM, flash for 1/4 sec on boot
    led = machine.Pin(23, machine.Pin.OUT)
    ledpwm = machine.PWM(led)
    # Get the ESP32 unique ID as a string
    uid = ''.join(['{:02x}'.format(x) for x in machine.unique_id()])
    # Check every two seconds to get and update the light level
    while True:
        light_level = int(urequests.get(
        print ("Light level {}".format(light_level))

    So if you thought the wESP32 was interesting but would be too hard to get started with, think again!  There are still a couple of days left to change your mind and get your own wESP32 by backing my campaign! :)

  • Crowd Supply campaign now live

    Patrick Van Oosterwijck10/05/2018 at 21:40 0 comments

    The wESP32 Crowd Supply campaign is now live!  I have parts for about 230 units in-house, so if you want one before the end of the year, at the time of writing there are less than 100 of those left!  If you order later, they will ship from a new batch which is scheduled for February 2019.

    As I mentioned in the first campaign update on CS, I received the production PCB panels for the first batch:

    I'm really pleased with how these turned out, my wasp is finally black and yellow as it should be. :)

  • Crowd Supply pre-campaign page live

    Patrick Van Oosterwijck09/05/2018 at 00:17 0 comments

    The wESP32 Crowd Supply pre-campaign page is now live!

    Check it out and sign up if you want to be notified when the campaign goes live!  There will be some early bird specials so signing up may land you a special deal. :)

  • Coming to Crowd Supply!

    Patrick Van Oosterwijck08/31/2018 at 18:43 0 comments

    The wESP32 is coming to Crowd Supply!  After seeing how successful our #LiFePO4wered/Pi+ campaign was, it made sense to repeat the same thing for the wESP32.  I hope to have the campaign up very soon now so you can start ordering!

    I've been very busy the past week with ordering boards, ordering components, and coming up with marketing materials.  A campaign video is in the works, and we need demos to show off some cool stuff you can do with the wESP32.  One simple idea was to make a "remote status display" you can send messages to:

    You'd probably want a bigger screen for the real deal, but is conveys the idea. :)

    @martinschki had a good question in the comments: "How much heat do they emit under a low power application?"  I've been doing tests and taking thermal pictures at high load, but I never thought of doing it for low loads!  And in applications such as his where things get built into a wall this is important.  So here's a thermal image under low load, running the demo shown above:

    So it looks like the hottest thing on the board is the Ethernet phy chip.  At 51°C I don't expect any problems for having it in a wall.  But if you're going to use this to build an environmental sensor, you definitely need to keep this heat in mind when you design your device or your readings will be way off!

  • Final performance checks

    Patrick Van Oosterwijck08/21/2018 at 18:19 0 comments

    I had left off my data performance testing last time wondering why the iperf UDP data rate was so low.  Well, @aenertia on Twitter gave me a hint: you need to specify the amount of bandwidth you want to test on the client side, otherwise the UDP test defaults to 1 Mbit/s!  So, just an average case of operator error. :)  The iperf on ESP32 example code is too simple and doesn't provide / need this option, and I haven't played enough with this kind of stuff before to know things like that.

    Here are the results for UDP when the wESP32 is the client (outgoing traffic):

    Around 70 Mbit /s, nice!

    So to test server, I used the following command on the client:

    iperf -c -i 3 -t 60 -u -b 100m

     This sets the target bendwidth to 100 MBit/s.

    Here are the results for UDP when the wESP32 is the server (incoming traffic):

    Wow, >90 Mbit/s!  That's close to the theoretical maximum!

    Now I'm pretty sure that from the moment the ESP32 would start to do anything with this data other than throw it away, the data rate would go down, but it's still nice to see that the Ethernet data system as implemented on the wESP32 performs very well.

    One last thing left on my list to validate the design was to test power performance when the 5V power option is selected by bridging the solder jumper.  As mentioned before, the whole power system is optimized for 12V power, and the 5V option was a little bit of an afterthought but it could be useful to many people.  So how does it do?

    In my first test I was really pushing it:

    Trying to push >2A through a power path that was designed for 1A: not a good idea.  That poor diode was frying, but it lived.  So, intermittent 10W may be possible at 5V, but don't run it like this continuously.

    Here's a more moderate test:

    That's better.  At 6W output (1.2A), the diode temperature isn't so bad.  Still, when running at 5V, your continuous average load should probably be kept below 5W.

    These results are fine though.  If you need high power, use 12V.  It keeps the currents much more reasonable.  If you really need high power at 5V, add your own buck converter.  The on-board option for 5V will likely still be very useful for the majority of people who need 5V in their system though.  5V sensors, keypads, displays, etc. usually don't need that much power.

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Enjoy this project?



Tom Aubier wrote 12/31/2020 at 12:59 point

Hi, I’ve encountered an issue while trying to run an MQTT client on the wESP. I’m using the simple client library provided on the MicroPython GitHub repository and everything appears to be functioning flawlessly when testing the code in the MicroPython WebREPL. However I get a `IndexError: list index out of range` error as soon as I try running it in the `` file or thought the serial prompt.

The issue seem to be related to the socket library failing when initiating the connection to the MQTT broker however I’m unable to find any way around this problem. Have you ever encountered something like this?

Btw I've provided more detail on this issue on this post:


  Are you sure? yes | no

Patrick Van Oosterwijck wrote 01/05/2021 at 18:48 point

Hi Tom,

I hope someone else can help you with this, since this very much seems like a software issue internal to MicroPython, and I mostly keep myself on the hardware side of things. :)

It looks like you accepted an answer for the StackOverflow post so this is resolved?

  Are you sure? yes | no

MrNoname3 wrote 04/16/2020 at 14:44 point

Hi everyone,
I want to build my own ESP32 ethernet PCB to a specific application and I have a question. I need an ATTINY85 to my project too and I want replace the PMS150C with this ATTINY. Can you share the PMS150C code, please? I just want to see the delays and I/O states of the reset.
I read this article:
And this is my hypothesis:
1. Usb serial programmer resets the ESP and the PMS150C
2. PMS150C oscillator enable pin go to LOW (the oscillator is disabled).
3. PMS150C PHY enable pin go to LOW (the PHY is disabled.)
4. 200ms delay in PMS150C.
5. PMS150C oscillator enable pin go to HIGH (the oscillator is enabled).
6. 100ms delay in PMS150C.
7. PMS150C PHY enable pin go to HIGH (the PHY is enabled.)
I saw the 2. oscilloscope picture on the link given above. I'm not an oscilloscope expert so I didn't exactly understood. Should I make between point 5 and 6 the PHY enable pin HIGH and immediately LOW before the delay, or what is that?
Thank you for your help!

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 04/16/2020 at 15:59 point


I don't have access to the PC that has that code right now (home due to Covid19) but the functionality is pretty much as you describe.  The thing that confuses you is when the PMS150C is not yet out of reset, the PHY enable is high (weak pull up) before the code runs that pulls it low.  This doesn't seem to cause any issue.  A similar thing was happening on the oscillator enable, but there I had to add a pull-down to prevent this, otherwise the PHY still didn't initialize correctly.

So, the whole sequence is:

Pull-down on oscillator enable to default low -> ESP32 EN / PMS150C reset goes high -> PMS150C boots and pulls both oscillator and PHY enable down -> Wait 200 ms -> Pull oscillator enable high -> Wait 100 ms -> Pull PHY enable high.

  Are you sure? yes | no

MrNoname3 wrote 04/16/2020 at 17:12 point


Thank you for your answer! Now I understand everything.

  Are you sure? yes | no

roma wrote 08/24/2020 at 09:43 point

Hello Patrick. I am making a similar project, but for automotive use (CAN/KLINE/ENET and similar protocols). I have made quite of esp32 test boards too, still not finished yet. My question is - why you actually have to reset the PHY? I never had any boot issues (could well be my luck), and I am just delaying everything from ESP32 on the boot, so RMII is not engaged by any means, and they are just pulled high (startup delay which is less than 100nF charge time ).

I am just pulling low the oscillator EN with 10k resistor, and then supply HIGH with IO14. Pin 15 (nRST) of LAN8720 is pulled high via 4.7k resistor, and loaded with 100nF ceramic capacitor. Driving GPIO0 as ref clock input. Any suggestion what can go wrong with such setup? The RMII being high could affect LAN chip?

Many thanks in advance.

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 08/24/2020 at 17:04 point

@roma It's been a while since I last looked at it, so I'm a bit rusty on the details. I think it works fine to control the PHY reset and oscillator from the ESP32 if you have available I/O to do it.  For the wESP32, I wanted to keep as many I/O available to the user, since so many were already in use by the RMII bus.  So I wanted an external solution, that wouldn't take up ESP32 I/O or rely on ESP32 code, to bring up the PHY correctly while not interfering with ESP32 programming.

I think the key things are:

- If ESP32 EN is low, make sure the oscillator is off and doesn't put the clock on IO0 since it may be in use for programming.

- Either after EN release or cold boot (power up), make sure the oscillator starts before the PHY reset is released.  The datasheet specifically says clock must be present while in reset to reset correctly.

- Then release the PHY reset.

There are various ways to accomplish this.  I first followed the way Olimex had done it with a voltage detector with delay, which seemed to work on my prototypes but proved unreliable in production, with 10% of boards not initializing correctly.  Then I went with the PMS150C solution, which has been working 100% reliably.  I think the key is that it programmatically guarantees the correct sequence, and is not dependent on variations related to RC component tolerance, reset threshold variation, oscillator startup time, etc.  If you can do the same with ESP32 I/O, it should work as well.  But if you mix RC timing into it, you may see problems.

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roma wrote 08/26/2020 at 20:57 point

Hello @Patrick Van Oosterwijck ,\

Many thanks for detailed answer, I really appreciate. I understand your intentions with many GPIO's, and your solutions does sound bullet proof.

I still have couple of question:

- Could you sell few of PMS150C's? I've heard you've got plenty :)

- Could you share contact for purchasing reprogrammed units, along with the firmware? For my production purposes, it needs to be on a scale.

And on the technical side. On your schematics I can see that refclock (pin 14) of LAN8720 is not wired. According to the datasheet, its either INT or output clock from internal oscillator (25Hz). I am wondering why you don't have it pulled high - could this be a problem of those 10% of units?

Now, regarding clock setup for RMII.

Here's a quote from LAN8729 datasheet:

///////////////////////////////////////////////////////////////////   REF_CLK Out Mode

To reduce BOM cost, the device includes a feature to generate the RMII REF_CLK signal from a low-cost, 25MHz fundamental crystal. This type of crystal is inexpensive in comparison to 3rd overtone crystals that would normally be required for 50MHz. The MAC must be capable of operating with an external clock to take advantage of this feature as shown in Figure 3-8.
In order to optimize package size and cost, the REFCLKO pin is multiplexed with the nINT pin. In REF_CLK Out mode, the nINT functionality is disabled to accommodate usage of REFCLKO as a 50MHz clock to the MAC.

Note: The REF_CLK Out Mode is not part of the RMII Specification. Timing in this mode is not compliant with the RMII specification. To ensure proper system operation, a timing analysis of the MAC and LAN8720 must be performed."


Furthermore, it supports 25Mhz clock to be supplied on XTAL1 (XTAL2 should float in this case), which will make it output 50Mhz on pin 14, thus providing an external RMII clock for GPIO0. Price of  25Mhz is similar to the one you have  installed of 50Mhz.

All of the above is configured with boot-stapping pin nINTSEL to low. So, in this setup having nRST low would also release GPIO0 from being affected during boot (it does not output refclock when in reset), hence only one "delayed" startup pin, either by GPIO or some simple delay IC (or even a capacitor?). I would appreciate your suggestions.

Do you have any contact outside hackaday for the matter of  PMS150C's or perhaps other projects?

Kind regards,

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 08/26/2020 at 21:54 point

@roma Interrupt mode is selected for pin 14 by means of the LED2/NINTSEL pin that is pulled up.  Since the interrupt is an output and not used, it can be left unconnected.
Let's discuss the PMS150C in private chat, I'll give you my email address.

  Are you sure? yes | no

Patrick wrote 03/10/2020 at 19:03 point

I created an Eagle library footprint for anyone who wants to use it. It should be good, but I recommend someone double-check my work. Let me know if there are issues.

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 03/10/2020 at 19:32 point

Thanks Patrick!

I looked it over and everything seems to line up, but it looks like on the GPIO header the pins are reversed left-to-right from pin 7 and up.

  Are you sure? yes | no

Patrick wrote 03/10/2020 at 20:47 point

Yup, device package had mixed up pin numbering, silly me, should be all fixed now.

  Are you sure? yes | no

lathoub wrote 03/06/2020 at 13:12 point

Hi everyone,

I just got me hands on the wESP32 and the webserver example is running just fine in the Arduino IDE. I want to use my existing Arduino <Ethernet.h> code on the wESP32, but there are not a lot of examples around. I'm looking specifically for example sending UDP packets.

Also, can I use the wireless capabilities of the wESP32 at the same time as the wired capabilities?


  Are you sure? yes | no

Patrick Van Oosterwijck wrote 03/10/2020 at 19:15 point


Wireless is still available, but there may be some limitations on using wired and wireless at the same time that are mostly related to how deeply you dive into the software.  I'm not an expert in the software side of ESP32.  I have tested Espressif's WiFi to Ethernet bridge code successfully on the wESP32:

Arduino may be too high level to be able to use both though.  As far as I know, the initialization code ties the TCP/IP stack to either interface, but not both at once.  Though I may be wrong, like I said, I'm not an expert on the software side of things.

  Are you sure? yes | no

Petr Karliak wrote 01/07/2020 at 10:26 point

Hello Guys,

I have to use a WatchDog on wESP32 to check and reset in case of freezing the Arduino core, but I managed to set it to Core0 and Core1 (Arduino). But I haven't enabled Wifi, so Core0 is idle, so it is happening that it is restarting all over again and again. I can't load new program to disable it down. I tryied the python tools, but with no luck. Anyone could help me what to try except manualy change the chip (whole ESP32) on wESP32?


  Are you sure? yes | no

Patrick Van Oosterwijck wrote 01/07/2020 at 15:56 point

Sorry I wasn't able to help you with this problem Petr, let's hope someone else here knows more about this.  Anyone?

  Are you sure? yes | no

Ashley wrote 12/06/2019 at 14:30 point

We are based in South Ontario Canada.  I already have one of these for testing for a new product we want to sell, i have a few questions and wishlist items:

- How do i upload code via Ethernet only (not USB)?  i cant find anything on the net / youtube with regards MicroPython and squirting it via Ethernet, they all reference USB.

- Are you planning to do a 802.3at version (30w [ish])?

- We need more analogue sensor pins, about 10 in total, i believe you have 5.  We need to control 5 LEDs and measure the current used by all 5 lines

- Does the 12v line have an internal current measurement sensor (i would assume it does being PoE driven), how would we access this via MicroPython?

- More RAM? although 4Mb (i believe this has) might be ok, more is always good, we have to get a whole website in this (the current one is 1.4Mb, might be slighy larger for this device but it all should fit)

For now the item we have should do as a really good start, we will likely need them by the multiple 10's or 100's once its all working, this project is live and R&D is working on the board now to try and get the program running we need.

Many Thanks

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 01/07/2020 at 16:29 point

Hi Ashley,

Sorry I didn't see this sooner.  I wish the system was more reliable in sending notifications when someone comments.  To make sure you get prompt responses you can try instead.  To answer your questions:

- Espressif supports OTA in IDF ( but it seems this hasn't made it into MicroPython yet, although there's work done for it (  If you just need to be able to update your MicroPython code it may be possible to implement your own system that updates the files in the filesystem, but if you need to update the MicroPython runtime as well, something more like the linked PR is needed.

- I'm not actively developing a 802.3at Type 2 (25W) system at the moment, but it's a natural progression that's definitely on the roadmap.  To limit risk I stuck to Type 1 (13W) this round, but a follow up product will go to Type 2.

- It's unfortunate but the Ethernet PHY interface takes up a lot of ESP32 pins so there aren't that many left for the user.  That said, to be honest the ESP32's ADC is pretty crappy.  You're much better off to add an external ADC that you control over I2C or SPI.  Such chips are pretty common, or add an external low cost ADC such as an EFM8 for the low level control and excellent analog peripherals.  I've done this for customer projects and the results are much better than using the ESP32 ADC.

- The 12V line does not have current sensing that is accessible from the ESP32, the PoE controller does this on the primary side.  A low-side current sense resistor, read by an ADC input is a simple way to add this function.

- I think you're mixing up RAM and flash sizes, but you're right that the standard ESP32-WROOM module may be a bit tight for large web content.  There is an ESP32-WROOM module with 16MB of flash though if you need it.  For bulk orders I can have this module populated instead.

  Are you sure? yes | no

graeme woollett wrote 11/19/2019 at 23:42 point

Hi Patrick

I've bought 5 boards and 2 have died.  First one the Phy gets hot, ethernet lights  don't come on, doesn't obtain an ip address.  Now a 2nd one won't get an ip either, no ethernet lights.

Seems that LAN PHY has died in both cases. hasn't been altered in either case.  

Do you have any advice on how to stop them dying?

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 01/07/2020 at 16:35 point

Hi Graeme,

Sorry about the late reply, the site didn't notify me and I was too busy to check here regularly.

This is odd, the only time I've seen PHY chips die has been when the ESP32 GPIOs were not configured right for the board, but if you are using the stock MicroPython and, and don't reconfigure the pins afterward, this should not be the case.

If you're willing to send them back to me I'd like to do a postmortem and repair or replace them.  Please contact me at to arrange this.

  Are you sure? yes | no

ego wrote 10/10/2019 at 11:27 point

Hi Patric,

Is there a physical dimensions document?

Even more helpful would be an eagle library like there is for arduino, raspberry pi, etc.

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 01/07/2020 at 16:39 point

Hi @ego,

I've added wESP32-3-mechanical.pdf to the files section.  Let me know if that doesn't cover all the dimensions you need.  This will be added to the next revision of the manual as well.

  Are you sure? yes | no

wburchard wrote 05/09/2019 at 23:48 point

How much do these boards cost?  Do they have a USB port on them?

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 05/10/2019 at 18:13 point

They are in pre-order on Crowd Supply at the moment:

More stock is being built right now.  The USB module for programming and terminal I/O is optional, choose the kit to have it included if you need it.

I am trying to find ways to get the cost down but with the meddler-in-chief's efforts to hamper international trade and make life hard for small businesses, this is unfortunately unlikely to succeed anytime soon.

  Are you sure? yes | no

Mat Smith wrote 05/16/2019 at 15:26 point

Hi Patrick! I'm really interested in wired ethernet for micros, and I bought the Olimex ESP32-POE, however my copy stopped working about 1 day after I received it. (It was able to get an IP address, then randomly stopped. I have always been careful about the lack of isolation between USB and PoE although that's unrelated...)

Anyway I'm really interested in this project, but for the number of units I'd like, the price would be too high. (Please note, I understand the economics of what you are trying to do, the difficulties with sourcing / shipping / tax etc. ... and if I were purchasing for business, there would be no hesitation over price as it seems like good value compared with the Atmel equivalent, the Ethermega PoE from Superhouse... but this is personal / fun.)

Long story short, I have three questions:

1a) Would you consider making a BOM and PCB designs open source?

1b) Would you consider providing basic support for someone like me to attempt to make it myself, if I could commit to documenting the process so that others could do the same. I understand if the answer is no to both of these!

2) I understand the PoE aspect pushes the price up. I would be prepared to forgo 802.3af for "DIY PoE", where I can use any voltage e.g. up to 28V. Would that be a simple option for bringing the cost down?

3) Sorry if I missed the detail somewhere online, but does your solution for PoE use the Silvertel chip? I saw these for around GBP 8.50 or similar price.

Here's my views on DIY PoE in my own blog post:



  Are you sure? yes | no

Patrick Van Oosterwijck wrote 06/25/2019 at 19:25 point

Hi Mat,

Since this is part of my business and how I make a living, it's always hard to figure out how much to give away and how much to protect.  In this case I've decided to open source the schematic but keep the layout proprietary since the wESP32's dense layout took a lot of work and optimization.  This approach has led to more business opportunities by creating derivative designs for companies that otherwise might not have happened.  Which in turn fund future development.

I've been absolutely swamped so it's hard to keep up with questions and free support.  I don't mind providing support to makers and hobbyists when I find the time.  Unfortunately there are a lot of freeloaders, business people that milk free information under the guise of wanting to do business and then turn around and use the free advise to have the work done on the cheap by someone else.  I'm trying to balance being a helpful community member and not being taken advantage of by freeloaders.

I'm not a fan of passive PoE but I can see it be useful in homes.  It's kind of the wild west though so I'm afraid if you make anything commercial in that space, people are going to be mad and complain about incompatibilities because nothing is standardized.  I didn't want such a support headache so I decided to stay away from it. :)

  Are you sure? yes | no

Barry Parr wrote 03/28/2019 at 00:30 point

In regard to the potential for taking out the PHY , Have you considered putting 50..100 Ohm series resistors on some of the IO ?

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 05/10/2019 at 18:17 point

I have considered it but not had the chance to experiment with it yet.  I need to find out exactly what breaks when the PHY dies, which I'm not sure how to do.  Any ideas?  I may have trouble finding room on the board for them too, considering how dense it is...

  Are you sure? yes | no

Barry Parr wrote 05/10/2019 at 22:08 point

The drive/sink current of a lot of pins on the esp32 is in excess of 20mA.

RXD1/0 of the lan8720 is 8mA so perhaps it's RXD0/1 that gets cooked when an input gets turned into an output accidentally . 3v3 / 8mA >> 412  . 470 Ohm series on those two might cover it . I have seen a few designs that have only 10 Ohm series on those pins .

  Are you sure? yes | no

Samuel Archibald wrote 03/27/2019 at 17:14 point

Are you able to use a SSL/TLS connection, and if so, does the ESP handle it as gracefully as it does on Wi-Fi?

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 05/10/2019 at 18:18 point

Hi Samuel, sorry for the late response.  Yes, SSL/TLS works as gracefully over Ethernet as it does over WiFi!

  Are you sure? yes | no

drewsed wrote 12/30/2019 at 03:00 point

What is a good way to jse TLS? Is it possible with Arduino? Or is it better with ESP-IDF?

  Are you sure? yes | no

2Fast2BCn wrote 01/14/2019 at 09:08 point

Unfortunately this stuff doesn't fit into an EU wall box. I'm going to assume you can remove the female RJ45 jack and solder the Ethernet cable directly onto the board but I'm afraid even then it will be to long. Why aren't these boards made more rectangular?

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 01/16/2019 at 16:38 point

Sorry, but when dealing with isolated power conversion and big parts like the flyback transformer and ESP32 module, there are limitations to how things can fall into place and still fit in a rectangular shape.

The RJ45 cannot be removed, it contains the Ethernet magnetics for data path isolation and the diode bridges for PoE power extraction.

The boards _are_ rectangular, I'm not sure what you mean with "more rectangular".  Do you mean more square?  What dimension change would make it fit in an EU wall box?

  Are you sure? yes | no

2Fast2BCn wrote 01/16/2019 at 22:15 point

Yes, more square. Sorry, English is not my native language.

What I was fishing for is that 55mm x 55mm would just fit in my wall box if the Ethernet connection is inward (or no RJ45 socket). I understand it's outward to allow for a case but in the wall it only hinders?

wESP32 could make for a killer room presence detection with the Bluetooth and also make all my switches smart.

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 03/11/2019 at 16:05 point

I wanted to mention that I am "thinking about" a wESP32 Mini, so maybe in the future I'll have something that fits your need.  As technology moves forward, new parts become available, and a new part from TI just caught my attention that does the flyback converter feedback through the auxiliary winding, removing the need for some secondary components such as the opto-coupler and reference.

I just need to find some time to play with them. :)

Also, no worries about hijacking the conversation piprog, you are providing relevant information. :)

  Are you sure? yes | no

piprog wrote 01/17/2019 at 22:46 point

You might want to check out the Shelly 1 - it is exactly for automating traditional switches (although wirelessly) and should fit in an European wall box. Works with Tasmota and thus with HA. I would LOVE if it were Ethernet + PoE, but I haven't found such a thing yet.  (Patrick: I'm sorry for hijacking the conversation but I feel it is relevant)

  Are you sure? yes | no

2Fast2BCn wrote 01/18/2019 at 09:04 point

Hello, Thanks for the suggestion. I have CAT5 running to all my toggle switches. I'm aware of the Shelly 1. A LOLIN D32 combined with a passive POE injector is cheaper and provides me with more flexibility. Unfortunately those are all wifi only and in my experience wireless networks work 99% of the time. So I prefer the 100% of Ethernet for a 100% wife approval factor ;-) because 99% is equal to 50% in Wife approval factor therms ;-)

  Are you sure? yes | no

piprog wrote 12/17/2018 at 12:08 point

Hi Patrick - excellent idea! I'd like to build a DIY HA/Security multisensor (like this: For this Ethernet+PoE makes much more sense (security) and I also have the cabling in the wall:), but the current price per unit is prohibitive for me. The above assembly is $15 all included, based on a $2.52 NodeMCU module. I'd need around 15-20 units and the price difference adds up quickly. How do you see, is there any chance this could go down in the $10s range anytime soon (like end of next year)?  (I understand that this is a custom project with very low volume and there are startup costs to be recovered, etc.) You could probably cooperate with one of the Chinese manufacturers to take over the assembly and pay you royalty (I know, can be shady) - e.g. the Sonoff guys could be one good candidate... I'm sure there would be ample demand if the price is right.

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 12/30/2018 at 06:06 point

Yeah that's the hard part.  The cost of the ESP32 module is pretty much irrelevant to the total cost at the moment.  The PoE parts are the biggest cost adder, so I'm not seeing this end up being in $10 range any time soon.
I do intend to get this produced in China in the long run, but I need to find a good CM first.  My first try with Boktech wasn't successful unfortunately.

  Are you sure? yes | no

Vipul Garg wrote 12/03/2018 at 14:35 point

Is the hardware is open source, if it is then where i can find pcb files 

  Are you sure? yes | no

kesh27 wrote 10/24/2018 at 18:10 point

How are you hoping production would look after the crowd supply campaign is finished?  I got in early on the campaign for half a dozen to experiment with for campus/dc monitors. If cost and volume numbers are good, we would be interested in 50-100 units and I'm curious how that might look in the new year?

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 10/24/2018 at 18:30 point

I will definitely keep producing these after the campaign.  The campaign is just to get eyeballs and get them in people's hands to start designing, but I'm expecting this to be more of a B2B / bulk product once people have designed something with them and put it in production.

I'm keeping an eye on orders and will soon be starting procurement for the next batch, which I expect could be produced by late December / early 2019.

  Are you sure? yes | no

aloismbutura wrote 09/16/2018 at 14:25 point

I just subscribed to your crowd supply campaign. My slight request is on the footprint. The WROVER and WROOM32 have compatible footprints on a PCB. Check the REV4 of the ESP32 devkit-c. This will allow upgrading of the ESP32 module on the board or even offering the WROVER as a different tier on the campaign due to the larger RAM/SPI flash benefits.

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 09/16/2018 at 18:22 point

Unfortunately my layout is really dense to try and keep the board as small as possible, so there's no extra room on my board to accommodate the larger WROVER module.

  Are you sure? yes | no

Emanuele Tessore wrote 09/12/2018 at 16:06 point

Hi there, this is great stuff! I'll use it to convert my light switches to smart switches and eventually drop a bunch of sensors inside and outside my home!

Have you tried any sort of remote programming on this board? for example TFTP or, even better, network boot.

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 09/12/2018 at 16:28 point

I've been amazed at what functionality is already available in some of the software frameworks that exist for the ESP32.  That said, I'm more of a hardware guy myself than software or application, so I'm very interested in what OTHERS will be able to cook up with these boards. :)

  Are you sure? yes | no

Emanuele Tessore wrote 09/12/2018 at 17:48 point

Thank you so much for beeing an hardware guy, cause I've tried to wire route a simple flip-flop button debouncer with some bad results :D.

I can't wait to have a couple of these on hand :) First of all I'll try to make a light switch that uses no mains power and comunicats to a central server (something like a Raspberry) where some logic decide the light to be turned on or off... 

I've a proof of concept running on an ATmega328P (Arduino) but I'm stuck on finding a board small enought to be mounted inside the electrical box and with a decent amount of memory and wired network. 

Your board will also save me from wiring all the boxes with a low voltage CC line :) Best of all this board will probably save me from using some (very pricy) KNX devices.

So I'll need a sample of 3 boards for development and if everything on my side works a grater batch (maybe 50 pieces) in something like 6 months... Are you planning to have some future run or make these boards available on demand in reasonably small batches?

Thank you, again :) Cheers

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 09/12/2018 at 18:25 point

Yes, the Crowd Supply campaign is just to get as many boards as possible into the market quickly and to establish demand. Later they will be available for sale through various channels including Tindie.

  Are you sure? yes | no

CLQ wrote 09/07/2018 at 09:33 point

Hi everyone,

It's really an awesome project. 

Have you planned to share the software ? Did you used ISP-EDF or somethong else (ESP-Arduino, so on) ?

  Are you sure? yes | no

Patrick Van Oosterwijck wrote 09/12/2018 at 16:26 point

I hope to have broad software support.  I've tested with ISP-IDF, Arduino, Lua-RTOS-ESP32 and MicroPython up till now.  I have pull requests in to upstream board support in arduino-esp32 ( and Lua-RTOS-ESP32 (  They are very easy merges but up till now they haven't been pulled in yet, so if you can add your voices to those projects to have them pulled in that would be helpful. :)

  Are you sure? yes | no

fabian wrote 09/01/2018 at 17:55 point

ideal for tor server. Plug in bibliotek or other place and increase tor network speed and anonimity

  Are you sure? yes | no

martinschki wrote 08/27/2018 at 18:04 point

Great Project!!

Looking for something like that for a loooong time!!!

I want to use these as room controller with a BME280 and a light sensor. Nothing fancy at all. Just sending sensor data every couple of seconds to a MQTT server.

They will go into a wall so my only concern and also question is: How much heat do they emit under such a low power application?? 

Since the sensors basically cover the hole they are put into it would impact the measurements...


  Are you sure? yes | no

Patrick Van Oosterwijck wrote 08/31/2018 at 18:44 point

Thanks Martin!

I quickly did a test under low load and put a thermal image up so you can check it out, it's in this project log:

  Are you sure? yes | no

martinschki wrote 09/20/2018 at 08:53 point

thank you Patrick, looking forward to your campaign 

  Are you sure? yes | no

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