I'm puzzled by Espressif's naming here. We had the ESP32-S3, so "S31" sounds like "S3, variant 1," but this part doesn't really look like a simple S3 variant. And then there's an ESP32-E22, but no E21 or even a plain E2 anywhere.<p>Edit: found an article explaining some of their naming logic, and said that the SoC naming will get its follow-up article, but sadly it never happened.
<a href="https://developer.espressif.com/blog/2025/03/espressif-part-numbers-explained/" rel="nofollow">https://developer.espressif.com/blog/2025/03/espressif-part-...</a>
It reminds me a bit of the new STM32s (STM32MP2) which are actually 64 bit, but they kept the name STM32 because everyone knows it
I stopped following the producer logic when Intel went from Pentium 4 to Pentium D
Interesting that they made a new chip with BLE+BR/EDR again. all the chips after the original ESP32 were BLE only.
Hope this chip has good low power options so we can use it in Bluetooth audio workloads.
It would be good if this chip had good idle current comparable to other MCUs. I have used the ESP32S3 and it's idle current with the radio enabled, but not transmitting, is quite terrible.<p>My application needed both can bus and Bluetooth (though no wifi) so the S3 was one of the only options available. I'm sure the high current draw is because the wifi and ble share the same radio?
They claim that the chip has an "MMU". But unfortunately this doesn't seem to be a true RISC-V MMU (according to the Sv32 specification) integrated into the CPU core itself, but just a peripheral designed for memory mapped SPI flash and PSRAM. So as far as I understand there is no true process isolation with page faults and dynamic paging.
I believe this is the first ESP to gain Ethernet capability?<p>I totally wish that a board would come with PoE…<p>Because as it is right now, powering a fleet of those with USB power supplies is annoying as fsck…
Nah, ESP32's have had ethernet capability for a while and ESP-IDF supports it well. I've been using one I built for 5+ years now. Unfortunately RMII (ethernet phy) interface takes up a lot of the GPIO pins. This part looks like it'll remedy that issue.<p>There's two ESP32 boards that have been around for a while with PoE:<p>- <a href="https://www.tme.com/us/en-us/details/esp32-poe/development-kits-for-data-transmission/olimex/" rel="nofollow">https://www.tme.com/us/en-us/details/esp32-poe/development-k...</a>
- <a href="https://wesp32.com/" rel="nofollow">https://wesp32.com/</a><p>I'm more hopeful for single-pair ethernet to gain momentum though! Deterministic, faster than CANBUS, single pair, with power delivery:<p><a href="https://www.hackster.io/rahulkhanna/sustainable-real-time-lab-monitor-using-spe-2a38a6" rel="nofollow">https://www.hackster.io/rahulkhanna/sustainable-real-time-la...</a>
Waiting for my ManT1S:<p><a href="https://www.crowdsupply.com/silicognition/mant1s" rel="nofollow">https://www.crowdsupply.com/silicognition/mant1s</a>
SPE with multidrop and PoDL would be awesome ! They are working on that and it will be everywhere.
The original ESP32 has Ethernet as well, I believe in the form of RMII. Then it has been removed from the chip, never specified the reason.
This would be great indeed.<p>On that note, why does the PoE capability often add such a big proportion of the price of various items? Is the technology really costly for some reason, or is it just more there's fairly low demand and people are still willing to pay?
PoE is not obvious to implement (take it from someone who has done it with a fair share of mistakes), uses more expensive components that normal ethernet, takes up more space on the board, makes passing emissions certification more complex, and is more prone to mistakes that ruin boards in the future, causing support/warranty issues. In other words, a bag of worms: not impossible to handle, but something you would rather avoid if possible.
A full-module add-on in this power class is about $7 at 1,000 unit scale [0]. It would be around $3 with your own custom PCB design in terms of BoM addon at scale. That’s power only. Add another dollar or two for 10/100 PHY.<p>The trick is as others have said in what adding it to your design does in terms of complicating compliance design.<p>[0] <a href="https://www.digikey.com/en/products/detail/silvertel/AG9705-2BR/21187225" rel="nofollow">https://www.digikey.com/en/products/detail/silvertel/AG9705-...</a>
PoE power supplies need to be isolated (except in rare exceptions) and handle much higher voltages than common USB-C or wall wart power supplies.<p>They have to use a transformer and a more complex control strategy, not a simple buck regulator with an inductor. PoE inputs need to tolerate voltages several times higher than the highest USB-C voltages, so more expensive parts are used everywhere.
It sounds like the PoE spec was designed before the arrival of “IoT” type things like the esp32, raspberry pi’s, etc.<p>How much of the complexity is a “fundamental electrical engineering problem” and how much of it is just a spec written to solve a different set of problems?
Ethernet is <i>already</i> one of the most expensive standards because you need magnetics for isolation. Adding power on top of that is genuinely expensive.
Whenever you combine two things into one, the complexity and cost go up considerably. A regular coffee machine is pretty cheap. Add high pressure so it can make espresso and it gets considerably more expensive. Add milk so it can make cappuccino, again more complex and expensive. The same holds for electronics. Isolating power when it's alone is fairly straightforward. It gets considerably more tricky and hence more expensive the moment you want to place any kind of a meaningful data signal in its vicinity.
I’m sure the other commenters are right, but I’m guessing market segmentation may play a role here too.
> Because as it is right now, powering a fleet of those with USB power supplies is annoying as fsck…<p>Therefore, wifi is more convenient than ethernet.<p>You don't need long cables, just a local power source.
> You don't need long cables, just a local power source<p>Which means batteries that have to be replaced and maintained or cables... So ethernet with PoE or even better SPE (single pair Ethernet) with PoDL (power over data lines which is PoE for SPE) is the best from my point of view
Well, yes, but then you need to be "in range" of PoE switch and drag the ethernet cable from it vs the nearby socket. Still, nice to have options
I mean, if I just look at my house. There is just one ethernet outlet, but many power sockets. If I want to connect devices all over my house, the best way is to use wifi and usb power adapters. Not ethernet.<p>Both solutions require 1 cable per device, but the first solution would require only short and thin cables, and the second solution would require very long cables which I don't know even how to do properly without milling my walls.
Yep. Mains electricity is ubiquitous, highly interoperable, very reliable, very high power available per drop, can be outdoor capable, common standards, understandable by users, requiring no active components, with many on-call experts available who can come to fix problems or extend/alter connectivity. Mains power wall plates with inbuilt USB power outlets are even available at quite small cost if the look of the bigger plug and wiring is not appealing.<p>PoE is much fewer of those things. Difficult to recommend it these days with wifi being fast and reliable and so widely used. Certainly not for average residential user.
Esp32 's wifi is only 2.4ghz though.
Can't you run a 5V supply from where your router is all the way to every god damn device in your house, and then pretend the wifi is also going through it? If you just want it to be inconvenient, there's no reason to let a lack of PoE stop you!
I don't understand what possesses these folks to continue making 2.4ghz devices. I understand there are use cases for low bandwidth, high range. But surely we've passed the point where that is more desirable to most than lower latency and high throughput, right?
HN title entropy record?
I don’t trust Espressif’s releases, I am still waiting for ESP32-P4 to hit distributors.
It is now more than 2 years and 3rd chip revision
Can also be ordered on JLCPCB in a custom PCB:
<a href="https://www.lcsc.com/product-detail/C22387510.html?s_z=n_ESP32-P4" rel="nofollow">https://www.lcsc.com/product-detail/C22387510.html?s_z=n_ESP...</a>
I assume their chips don't really exist until they're actually supported by ESP-IDF. The ESP32-C5 was announced in June 2022, received initial support in -IDF in August 2025, and more complete support in December. It seems to have only recently started getting third party dev boards.
Argh…Wifi 6 , but 2.4ghz.
I hope this one has multiple radios so you can actually use BT/Wifi/Thread simultaneously.
Love ESP boards, and with Raspberry pi pricing though the roof, I’m hoping more will discover the love of getting the job done on a 10mm2 package.<p>I suspect a lot of the things people are using RPi for are better served by things like this (and virtualisation for the heavier end)
Oh neat. Zigbee support.<p>I wonder if I at some point can create low power devices with EspHome for home assistant. I assume this should use less power than connecting to wifi?
You already can with nRF52 boards. Presumably they'll add ESP32 support soon too.<p><a href="https://esphome.io/components/zigbee/" rel="nofollow">https://esphome.io/components/zigbee/</a>
The C6 and the H2 already support ZigBee. Their SDK has a thin layer on top of zboss.
> high-speed 250 MHz 8-bit DDR PSRAM with concurrent flash and PSRAM access<p>This is perhaps lost in the noise but IMO a large deal. PSRAM starting to get serious bandwidth.
For reference, the 4-bit PSRAM interface on the ESP32-S3 normally runs at 80 MHz (maximum 120 MHz) and shares bandwidth with the external flash.<p>I wonder if it will be possible to (ab)use the faster PSRAM interface on the ESP32-S31 as a general purpose 8-bit parallel interface, eg. for ADCs...
How do Espressif’s RISC-V cores compare to existing ARM or RISC-V options in terms of power efficiency (computational power / electrical power)?
Don’t know the specifics of the Espressif RISC-V cores, but in general they can’t really compete on those aspects with ARM.<p>ARM is a much more mature platform, and the licensing scheme helps somewhat to keep really good physical implementations of the cores, since some advances get “distributed” through ARM itself.<p>Compute capabilities and power efficiency are very tied to physical implementations, which for the best part is happening behind closed doors.
Soon espressif will add TPU to their chips.
Is there something that match those elsewhere ?
The ESP32 boards I own have bad support and are a bit of a hit and miss. (arduino nano esp32) Did this get better? Or is the support still messy?
That native sdk and the vscode plugin are very professional. There is a bit of a learning curve to get into it, but once you do, it's very functional and the developers are super supportive. They have fixed bugs for me in days.
Arduino nano are made by arduino using Espressif chips, and Arduino IDE support is indeed hit and miss.<p>ESP-IDF, the official C SDK, is a bit more work, and there is drama around platform-io, but it’s significantly more stable.
Don't use the Arduino framework, use ESP-IDF or Rust.
For those using PlatformIO, the folks at pioarduino[0] are doing a great job keeping up with Arduino Core 3.x support.<p><pre><code> ```
# platformio.ini
platform = https://github.com/pioarduino/platform-espressif32.git#55.03.37
framework = arduino
```
</code></pre>
[0]: <a href="https://github.com/pioarduino/platform-espressif32" rel="nofollow">https://github.com/pioarduino/platform-espressif32</a>
how's Rust on the xtensa cores ?
Roughly how much do you think this costs?
Does it run Linux?
Interesting.<p>Although, I'd like to seem some non-paid blogger head-to-head reviews benchmarking instruction cycle efficiency per power of comparable Arm vs. ESP32 Xtensa LX6* and RISC-V parts.<p>* Metric crap tons of WROOM parts are still available and ancient ESP8266 probably too.
Since the Snowden leaks in 2013, it just doesn't make sense that *any* foreign customers would put US technology inside their firewall. But they do.<p>It shocks me even more that any Western customer would do the same with network-connected Chinese chips. But we do.<p>The Espressif chips are truly incredible value, but what are we doing here?<p>Is there any doubt that these don't represent a major attack surface if a conflict were to heat up?<p>If you had network-connected chips of your own design inside every household of your adversary, what could you do with that?
It’s not like creating a chip gives you unfettered access to it. You _can_ add 0-day flaws and backdoors, but these can be discovered, leaked, etc. Has there been any case of such a backdoor built in consumer chips like theses? I’m not talking about CIA ops like snowden described, that’s supply chain interception. I mean, has anybody ever found such a backdoor?
Well, that depends on what you count as a backdoor, but Espressif has had some questionable flaws:<p>- Early (ESP8622) MCUs had weak security, implementation flaws, and a host of issues that meant an attacker could hijack and maintain control of devices via OTA updates.<p>- Their chosen way to implement these systems makes them more vulnerable. They explicitly reduce hardware footprint by moving functionality from hardware to software.<p>- More recently there was some controversy about hidden commands in the BT chain, which were claimed to be debug functionality. Even if you take them at their word, that speaks volumes about their practices and procedures.<p>That’s the main problem with these kinds of backdoors, you can never really prove they exist because there’s reasonable alternative explanations since bugs do happen.<p>What I can tell you is that every single company I’ve worked which took security seriously (medical implants, critical safety industry) not only banned their use on our designs, they banned the presence of ESP32 based devices on our networks.