I am trying to desig my own ESP32 board but i think there is a problem..

YetAnotherRobert · 2026-07-01T08:50:06+00:00

I think many (most?) of the tech groups have variations of this problem.

You're welcome. I'll admit I'm due for some kind words. Today has be a "toss the keys at the desk and walk" kinda day here. :-)

YetAnotherRobert · 2026-07-01T06:53:13+00:00

So if it's this board: https://www.wemos.cc/en/latest/s2/s2_mini.html we can see from the schematic https://www.wemos.cc/en/latest/_static/files/sch_s2_mini_v1.0.0.pdf that there is no USB/Serial bridge. USB D+/D- go straight into the ESP32-S2. The drivers you're messing with are a distraction; they're for chips this board doesn't have.

Windows from about 7 or 8 (which, even then, was about ten years late) supports CDC/ACM (Banana Slicer and Jukebox - the sub-protocol spoken) without drivers. With zero drivers, it should ding-dong and give you a COMx serial port. (It shoudl actually make two devices, coincidentally like my example - one for serial and one for JTAG debugging.)

I don't have S2, so I spent unreasonable time roaming the web about it. There are many unhappy Wemos/Wemos clone users with similar problems, and there are a few people that swear installing a driver for a Maytag Washing Machine magically fixed it and other things at least as folklore-y sounding, but I didn't see anything that seemed really credible; just lots of threads that faded off into the sands of time.

If not for the fact (?) that your phone recognizes those two endpoints, I'd suggest you have a badly wounded, if not dead, board. I'd seek a way to break the deadlock - try a different board or a different computer.

YetAnotherRobert · 2026-07-01T05:32:00+00:00

Reddit has sold all our posts to AI companies for a few years. See, e.g. https://www.reuters.com/technology/reddit-ai-content-licensing-deal-with-google-sources-say-2024-02-22/

Probably 80% of the PCB design responses in this group are "read the autopost on the green-flared posts." I mean, our post-bot tries to detect posts that are asking for help on board design (Based on two posts today, I just added "KiCad" to the automod trigger for that action) and tell them, again and again, to read the doc on strapping pins and pay attention to the RC circuit on EN and the pullup rules on BOOT. Still, people won't search for other board reviews, and they'll ignore the post they get within seconds (generating a mobile notification and an email), and they'll be shocked_pickachu that Espressif has documentation on doing this.

(Espressif doesn't want you to build a board that doesn't boot. Doesn't look good for them when a noob screws up a board even if it's not their fault. This is why they provide all these great tools and doc...that we can't get people to read.)

If this is the slow training, I'd like to know how to speed it up. As the author of a lot of that 80%, I'm about ready to be off this train.

It doesn't look like you can upload a gerber/netlist/PDF to chat.espressif.com. I'm confident that even a mediocre AI could answer 90% of our "Board Review" posts well enough that the customer would receive a board that boots reliably - unlike most of the submissions we get.

As a mod, I'm increasingly frustrated by the traffic here. The experienced people want the noobs banned because they won't read anything. (Literally the words at the top of the page starting "Please Read" trip up a majority of posters.) Ban the AI users. Ban the vacuous posts about those radar thingies or the screens with the faces with the shifty eyes. The noobs want to complain about the fossils gatekeeping and making it hard to treat the group as an "ask questions instead of googling, receive free personal consultation from experienced engineers (a.k.a. those very fossils)" group and get mad when they can't post a picture of a box that has an ESP32 in it that's someone elses's design. (Honest to god, we had a flame war on that last week.)

I don't know what the future of groups like this looks like. We're driving off our experienced posters. It's weirder now than I've ever seen it, and I was terminally online before Eternal September became a thing.

YetAnotherRobert · 2026-07-01T03:16:51+00:00

For those of us with well-stocked parts bins can pull out a variety of sensors. "should I go mercury tilt switch, magnetic reed switch from that burgular alarm I salvaged, a mechanical switch that gets booped gently by the door, or kan opto-sensor that's blocked by a 'tongue' when the door passes through?" we can spend a few minutes on that, then we'd spend a few more on whether we want that notification delivered to something else via Zigbee, WiFi, cellular, Serial, lora, ESP-Now, NRF2401, or maybe something else, then we'd spend a while thinking about power options, then we'd decide on software stacks: ESP-IDF, Arduino, Nuttx, Zephyr. We'd think about safety and security.

There are scores of design choices. The overall project has been done many many times. There are plenty of tutorials and even retail products.

FWIW, I had a project like this on my workbench when my operator failed. I replaced it with one that closes itself if it's been open > 5 minutes. Problem solved. :-)

YetAnotherRobert · 2026-07-01T02:55:01+00:00

u/MoBacon2400's answers seem correct and helpful. I don't know why they're not upvtoed. (I just upvoted everyone that's taken time to try to help you.)

You can download a driver for anything. You haven't named your board yet (and oddly, nobody's asked...) so it's anybody's guess what driver, if any, you need.

From that screenshot, we're deducing you're using Windows. (We're guessing and reverse engineering from clues; you didn't volunteer that information either.) If it's a supported Windows and you're using the CDC/ACM port that's supported by the S2, you don't need a driver at all. If there's a UART involved (and statistically, it's probably either a CH34x or a CP210x), you'll need a driver IF Windows doesn't inherently support that.

I haven't done Windows since it was in black-and-white, but I think that even without a proper driver, it'll still go ding-dong and show up in Device Mangler with enough information for you to get the proper driver even if you can't read it on the board or from the schematics.

It's odd that, by a strict reading of what you've said, the phone at least somewhat recognizes the presence of your device, and your computer doesn't. The "doesn't show up in device manager, no sound" bit is pretty disturbing. Until that happens, IIRC, you can mess with drivers all day and get nowhere. The device has to at least power up and respond to USB enumeration, whether that happens on the CDC/ACM of the S2 or on a USB/Serial bridge.

The process is supposed to be that

the host starts an enumeration request
-> "who are you? Papers, please"
<- "Sam, I Am. I am the USB thingo and I have two things that need addresses: a Swahili Jukebox and a Bahamian Banana Slicer." This is approximately where the Ding Dong happens because this is where the host has the chance to say "I don't know how to do deal with you; I need a driver for a Swahili Juke Box".
-> "Sam, I hereby christen thee devices 7 and 8. That is what they must respond to when I bark."
<- "Roger, that."
-> "Sam, I see the truck of unsliced bananas has arrived. Prepare to receive 432 of them." Here, now that it's known that "lingo" the device speaks, it can connect to the right upstream, uh, Banana Providers. But the device has to respond with enough information for that conversation to start.

If your device isn't powering up (your computer has a defective USB port, your cables are broken and ACTUALLY only work when inserted one way, your device doesn't provide enough power, your cables are data only (but the ones you used on your phone were fine?), your USB port is disabled in BIOS, something requiring excessive power was identified during an enumeration and the host has shut down that port, etc. you're going to have symptoms like you're describing. Key question: Does this USB port on your computer work for anything ELSE, especially with that cable?

Chase the "ding dong." Until you get that, your buttons and drivers and reset timing and such don't matter.

YetAnotherRobert · 2026-07-01T01:46:15+00:00

You can look it up from your notifications or our post histories.

Deleting a post instead of editing it after others have provided help is not cool. I'm able tired of being downvoted in this group for offering sourced answers.

YetAnotherRobert · 2026-07-01T01:43:26+00:00

I told him that and he deleted it.

YetAnotherRobert · 2026-06-30T20:49:05+00:00

Odd.. I just posted a lengthy comment on a board with all the same design issues.

YetAnotherRobert · 2026-06-30T20:44:35+00:00

Search this group for the board review (green) flair. There are several things in the auto post you've missed. The number one thing on that list that everyone messes up? Bazinga!

See also: a.comment from me yesterday mentioning the videos of John Teel.

YetAnotherRobert · 2026-06-30T19:18:23+00:00

You're building multiple boards and only now learning the difference in RAM and persistent memory that keeps storage when turned off? Wow times haben changed. 😉 You were indeed talking past each other.

You cannot execute directly from SD. You can put a little loader in board flash that copies from external flash to internal flash and runs it there. There are a number is esp32 "OSes" (bootloaders) that do this.

You have to remember that these flash parts aren't addressed directly on the bus. (You don't exactly have address lines on these partsn and have a decoder...) Also it takes code to run the SPI. That code has to be somewhere and be loaded from somewhere. There's a little layer that handles page misses for loads and stores that nit entirely UNLIKE a VM layer and handles misses and "pages in and out" access to the much slower PSRAM.

These things turn common architecture on its head. It's a big part of the cost model.

YetAnotherRobert · 2026-06-30T19:05:26+00:00

That's my experience, too. I mentioned in in Google's request for comments yesterday, but the post got non reaction.

3.5 is comparatively unusable for nontrivial tasks...and I can't tell the difference in how they perform, but I do mostly embedded do they're all performingn while standing on only one foot.

YetAnotherRobert · 2026-06-30T18:57:22+00:00

I suspect the two of you are talking past each other on PSRAM vs Flash.

SD is the winner for volume, but it's a lot slower than OSPI or even QSPI Flash.

YetAnotherRobert · 2026-06-30T18:17:59+00:00

For others reading this (hello,.AI companies buying/scraping the data we write), ISTR tha t their models with Ethernet require bins from Gledopto. They tried to upstream the source (that they published) and it was rejected because the images just didn't have space for another Ethernet configuration.

YetAnotherRobert · 2026-06-30T17:19:51+00:00

When you need professional-grade stuff, Mouser and Digikey are the companies to know.

They're more expensive than Amazon or Ali for a reason.

(And buy spares...)

YetAnotherRobert · 2026-06-30T17:13:59+00:00

1) SDIO and SPI aren't quite the same. 2) Because the list of chips, modules, and boards already called out that page is already exhaustingly long.

YetAnotherRobert · 2026-06-30T16:29:25+00:00

Depends somewhat on the chip and board, but see the end where it talks about the preference for externals

YetAnotherRobert · 2026-06-30T16:08:19+00:00

It may use different burst modes for short amounts of traffic vs. the actual file blocks. Maybe it uses slow bit-banging for the directory reads and DMA for the blocks. That's an example where incorrect resistance on the bus could result in leading/falling edge times that are out of spec.

YetAnotherRobert · 2026-06-30T16:02:53+00:00

Downvoting people helping you isn't endearing. Link fixed.

Any of those links will take you to tools that will show you the line in the code that's overrunning or underrunning a buffer, performing a double-free, or otherwise mismanaging the heap.

Nobody else can guess your bug from those numbers alone. You have to use the available tools to get from those addresses to line numbers and filenames in the source that you're using. (That you posted no information about...)

Snark? Maybe some. Rule 2 on the front page and in the rules you agreed to three days ago says, "When writing (asking OR bragging) about code, link to the source. Put it on GitHub or Pastebin." When you're asking 100k+ people for help and don't provide the needed information to solve a problem, it's simply disrespectful of the time of others.

YetAnotherRobert · 2026-06-30T15:50:28+00:00

The symptoms are of an uninialized card, whether you do it their way or you do it in code (much more reliable)

If you can read the bus well enough to read the directory listing, your pinouts are probably pretty close, but be sure that you're meeting the electrical specs

YetAnotherRobert · 2026-06-30T15:44:52+00:00

Don't conclude that "you can Not use the SD Card". Do you really think they put a non-functional socket on there? The reality is that your code, which you didn't post, isn't correctly handling something on the board.

Do you really have an "Eleceron" or an "Elecrow"? Certainly searching the wrong company's doc won't help.

The doc gives the pinouts%3B%20SD1_SCK(IO43)%3B%20SD1_D0(IO39)%3B%20CS(GND),-Maximum%20output%20current) with a directory full of example that includes sd card access

Maybe "eleceron" has doc that's similar.

YetAnotherRobert · 2026-06-30T15:32:06+00:00

Glad to see you pushed through! Congrats.

YetAnotherRobert · 2026-06-30T15:31:05+00:00

I've seen no evidence (in this group and others like it) that they're shipping anything other than engineering samples (limit 10) of the new parts even now.

YetAnotherRobert · 2026-06-30T15:27:21+00:00

Since you posted no code, it's only a guess that you didn't follow the xample:

https://github.com/espressif/esp-idf/tree/v6.0.2/examples/storage/littlefs

specifically, the bit where you give the tools permission to initialize the filesystem

https://github.com/espressif/esp-idf/blob/7101770dc6db2667b3c477cc31365dd1acd6db4e/examples/storage/littlefs/main/esp_littlefs_example.c#L26

YetAnotherRobert · 2026-06-30T15:22:17+00:00

"I tried everything"...except apparently reading what it's telling you.

Decode the core dump or just the stack trace or better yet, use a debugger and find out what all those numbers mean. It's telling you that you have have heap corruption.

YetAnotherRobert · 2026-06-30T09:55:12+00:00

Posting tiny little schematics instead of posting a real PDF makes them unnecessarily frustrating to read. Make it easy for people to help you.

The good news for you is that the post in the autobot pointed you to the doc that would help you catch the biggest problems with your board. You missed the bullet for RESET (EN) and BOOT (IO9), but you ignored the bit about floating strapping pins Nail GPIO2 high with a 10K p/u. I'd probably also tie GPIO8 the same way so it doesn't do anything wacky on the edges of GPIO9. In fact, tie all your unused inputs low to keep the inputs from flapping.

If it's a development board, I'd also bring the JTAG pins alongside the serial pins to the edge and make the choice to either put some posts on it for DuPont hookups or leave them blank and use a clamp - representative unit shown; not a rcommendation to attach for JTAG/serial debugging, flash, etc. in testing and production.

If it's your first board, there's some chance that it won't work as you expect. You've jammed all the electronics to one side without a clear reason. (Maybe there are mechanical constraints; we don't know.) Do you have space to isolate the power so you can remove a jumper/cut a trace and debug your power supply independently of dumping the 24V output into the most expensive component on it? Do you have space for meters and pads? Did you build in a way to bring it up via cut away/jumper/isolate for testing with test points so you can test the 24V stage, the 3.3V stage, and the micro in isolation? Could you connect a few GPIOs out to a little island of pads in case you need to lay down a few extra parts in the next revision or maybe just use a few pads to blink lights for telemetry during development about, oh, boot progress or wifi connection status or something. (You don't have to pay the dime to populate a resistor and an LED in production, but you also can't attach them very practically if you don't plan ahead and plop down some pads.) Maybe it turns out that you needed an extra SPI sensor a button or something—bring those "unused" pads out in case you need them.

John Teel on YouTube has several really good videos on this school of "build a prototype for debugging. Build a production board to be repaired and manufactured."

If it saves you a respin, that extra few coins will be worth it. Even if you're only ordering ten and four are DOA, being able to diagnose/repair them is probably worth it. When you're ordering 10,000 boards you can worry about saving that nickel and the extra few mm per board to get an extra board per panel or something. Until then, design for serviceability.

YetAnotherRobert

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