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• Revision 7 is available for sale!

  Patrick Van Oosterwijck • 09/30/2021 at 16:10 • 7 comments

  A little late posting here, but just a heads-up that revision 7 has arrived and is making its way to various distribution channels!

  New 4-layer PCB, much more decoupling capacitance on-board, RTL8201FI Ethernet Phy and now 16 MB of flash!

  Tindie: https://www.tindie.com/products/silicognition/wesp32/
  

  Mouser: https://www.mouser.com/ProductDetail/Silicognition/CS-WESP-04?qs=sGAEpiMZZMu3sxpa5v1qrriU3DaWTQdbHa4MxnML6FE%3D

  Amazon: https://www.amazon.com/Silicognition-wESP32-Isolated-Ethernet-802-3at/dp/B084RV91NQ/

  Note that the lead time shown on Mouser is bogus, they had 100 units shipped to them already.  Should ship much sooner than the lead time indicates.
  

• Documentation update

  Patrick Van Oosterwijck • 09/13/2021 at 17:59 • 0 comments

  A quick heads-up that I finally found the time to update the wESP32.com website with new information related to the changes in revision 7 such as 16 MB of flash and RTL8201 Ethernet PHY.  The product brief has also been updated, make sure to check the code examples to see the changes you may need to make to your software for this revision!
  

• Kingtop finished production

  Patrick Van Oosterwijck • 09/09/2021 at 16:30 • 0 comments

  A quick progress report.  MicroPython 1.17 dropped on September 2 2021 which meant that I finally had an officially released binary with support for the new wESP32 with 16 MB flash.
  

  To remove the biggest bottleneck in production called "me" from the equation as much as possible, I had my CM Kingtop build a fixture so they could program and test them, instead of me still having to do that with every board.  They built a nice fixture:

  Much better looking than my fixture hacked together from two perf boards. ;)  That worked, but hurt your hand when running too many boards.  Big improvement.

  Kingtop finished populating the through-hole parts and programmed and tested all boards:

  They reported two boards that failed on initial test, but they were able to correct the problem.  So an initial failure rate of 0.2%, and 0% after rework, that speaks very well to their build quality and processes.  Believe me, I've seen much much worse!
  

  They are ready to ship them now and it's still looking good for getting stock mid-September.

  Now I only have to harass Mouser some more to try and get them to send me a PO for the new part numbers generated for this revision, after begging for months already.  But why do something ahead of time when you can do it when it's too late, right? 🙄
  

• Revision 7 production progress

  Patrick Van Oosterwijck • 08/20/2021 at 22:00 • 1 comment

  After waiting for four months since I ordered them, Mouser finally shipped the SI3404A PoE chip to my CM, so they have started production.  I received this picture of the new PCBs:

  Looking good.  I think there shouldn't be confusion about which PHY this uses, since I have it in pretty big letters on the bottom.  Last night, I received this picture with surface mount components mounted:

  Nice progress!  You can see the new RTL8201FI Ethernet PHYs and the ESP32-WROOM-32E module with 16 MB of flash.

  Meanwhile, I have also managed to get a custom board config merged into upstream MicroPython so you can actually make use of all that flash memory!  Up till now, I used the generic ESP32 images but they are made to use only 4 MB of flash.  The flash memory will be partitioned with two nice 2.4 MB OTA partitions so we should be safe for a while as MicroPython keeps growing, and a nice 11 MB of flash will be available for the MicroPython file system!  I'm hoping that version 1.17 will be released soon so I can give an official release to my CM to program in to the boards.  As usual, the boards will also come with a custom boot.py file that will set up the LAN for you.  So if you use the built-in MicroPython, the change to a different PHY chip will be completely transparent.

  I also ran some more performance testing and compared performance of the old LAN7820AI with the new RTL8201FI using the latest IDF's ethernet iperf example.  It looks like the LAN8720AI is marginally faster with UDP, while the RTL8201FI is marginally faster with TCP.  Overall, performance seems to be just fine.  The following numbers are approximate:
  

  	LAN8720AI	RTL8201FI
  iperf UDP ESP32 serving	88 Mbit/s	83 Mbit/s
  iperf UDP ESP32 client	61 Mbit/s	60 Mbit/s
  iperf TCP ESP32 serving	23 Mbit/s	25 Mbit/s
  iperf TCP ESP32 client	27 Mbit/s	30 Mbit/s

• Bye bye LAN8720AI, hello RTL8201FI

  Patrick Van Oosterwijck • 05/27/2021 at 22:49 • 3 comments

  It had come to my attention that some customers had problems that some of their boards would stop working.  When they returned them and I did a postmortem, it was always the LAN8720AI Ethernet PHY that had died.

  Eventually I was able to recreate a setup that would reliably kill the LAN8720AI.  If I had a wESP32 connected to a particular PoE switch, with the USB programmer connected to a particular laptop, the chip would die when plugging in the Ethernet jack.  So I set out to try and determine root cause and find a solution.

  Doing some measurements on what exactly happened when plugging in the Ethernet using a battery powered oscilloscope, I could see some spikes occur on the 3.3V supply and ground when the cable was plugged in.  My theory was that maybe the charges on the various EMI caps connecting primary to secondary in the PoE switch power supply, the laptop power supply and the wESP32 would redistribute on connection and cause ground bounce that would for a very short time expose the LAN8720AI to out of spec voltages.

  Now doing these kinds of measurements, you're never really sure about what you're seeing, what's real and what's just a measurement artifact.  So I wasn't really sure, but it was something to go after.  I would try to improve supply filtering, add TVSes for ESD protection on the supply and signal pairs, and add filtering in the ground connection between the EMI cap and the circuit ground.
  

  I first changed supply filter caps on an existing board.  I tried larger bulk caps, and smaller close-to-the-pin caps for better response to high frequency spikes.  Didn't help.  I ordered TVSes, and added one to the 3.3V supply and filtered analog PHY supply.  No difference.

  I decided to create a new, 4-layer board layout with footprint for ESD protection on the Ethernet differential pairs, the supply, and a differential filter that would including filtering ground spikes that might be coming through the PoE supply's EMI cap.  I went to 4-layer with a 3.3V power plane adjacent to GND through 0.1 mm prepreg to provide improved HF power supply filtering.

  Here's the prototype:

  Here's the ESD protection chip I added to the data pairs, the little chip above the wasp:

  Aaaaand it didn't help squat. 😠  The PHY died just the same as before.
  

  Now what?  Stock was running low, and I really would rather not make another 1000 potentially troublesome boards that might die in some setups.  My goal is for the wESP32 to be powerful and reliable, able to take whatever you can throw at it.  Dying when connected to certain equipment just won't do.  I've only had a few customers complain about it, usually in some situation where there's external power, so it doesn't seem to be a widespread problem.  But still, I don't find it acceptable.

  I did some investigating, and found that in the years since the wESP32 was first released, the ESP-IDF has come to support more PHY chips.  It looks like IDF 4.x added more options, and the ESP32 Arduino core also already supports them.  In the mean time, MicroPython has dropped the IDF 3.x based images that supported Ethernet, but support may be coming in the IDF 4.x based images.  So, this opened possibilities.  IDF, Arduino and MicroPython support are the most important for me, other software is likely to follow as it gets migrated from IDF 3.x to IDF 4.x.

  I had tried to avoid changing PHY chips because I don't like forcing customers to have to change their software.  It's only a change in the PHY definition, so it's minimal effort, but it's still a change that needs to be made.  I had considered it a last resort, but after all this effort and killing tons of chips while testing, I had to finally admit defeat in my efforts to stop the LAN8720AI from dying.  I had really tried hard, tried everything I could think of to protect the chip, to no avail.

  So I set out to create a prototype with the RTL8201FI...

  Read more »

• Second production run

  Patrick Van Oosterwijck • 05/10/2019 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 Oosterwijck • 03/11/2019 at 16:09 • 4 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 Oosterwijck • 01/16/2019 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 board.led1.pin=-1 board.btn1.pin=-1
  

  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 Oosterwijck • 01/16/2019 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 Oosterwijck • 12/30/2018 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
    Serial_begin(115200);
  }
  
  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
      Serial_write(c);
      // 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*')
      time.sleep(0.1)
  
    print("Serial port detected, waiting for access...")
      while (not os.access(ports[0], os.R_OK|os.W_OK)):
      time.sleep(0.1)
      print("Testing wESP32-Prog...")
      test_ok = True
    s = serial.Serial(port=ports[0], baudrate=115200, timeout=0.1)
  
    s.setRTS(False)
    s.setDTR(False)
    s.write(b'0')
    res = s.read(1)
    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
  
    s.setRTS(True)
    s.write(b'0')
    if (s.read(1) != b'1'):
      print(colored("ERROR: EN not pulled low correctly!", 'red'))
      test_ok = False
  
    s.setDTR(True)
    s.write(b'0')
    if (s.read(1) != b'3'):
      print(colored("ERROR: IO0 and/or EN pulled low when both are asserted!", 'red'))
      test_ok = False
  
    s.setRTS(False)
    s.write(b'0')
    if (s.read(1) != b'2'):
      print(colored("ERROR: IO0 not pulled low correctly!", 'red'))
      test_ok = False
  
    if (test_ok):
      print(colored("OK! All tests passed.", 'green'))
      s.write(b'@')
  
    s.close()
    print("Please unplug wESP32-Prog.")
      while ports:
      ports = glob.glob('/dev/ttyUSB*')
      time.sleep(0.1)

   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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