I kind of wish these all weren't called ESP32. ESP8266 and ESP8285 -> ESP32 made sense, but now we have 10+ different versions with different features and different architectures.
Kind of like how in every thread involving a Raspberry Pi Pico (RP2030/RP2350), there's always someone confusing it with the single board computer version.
The ESP32 (Classic, usually WROOM-32E) is still usually what comes to mind when I hear ESP32.
Espressif is on fire! And the CPU even has SIMD instructions!
RISC-V cores is a big deal for embedded systems because now compiling for SoCs is only a matter of `rustup target add riscv32imac-unknown-none-elf` instead of downloading half-broken proprietary toolchains and SDKs.
Yes, but it looks like there is no hardware floating point. The description of the CORDIC module indicates fixed-point calculations, which is consistent with the lack of any reference to floating point.
I am happy the have CAN-FD and Motor PWM module, but nowhere did I see conversion times listed for the ADC. For motor control I demand 1uS conversion time or less, and in the last year I've switched from fixed point to floating point after holding off on that switch for ~15 years.
The datasheet apparently doesn't say, but judging by their other products' listed 12 bit SAR ADC sampling rates (and assuming this one is similar to what appears to be their standard ADC ) the conversion time will be on the order of 10uS.
It's not that important if you use current sensors on the motor phases. But then you're looking at HALL sensors or a shunt with a very high gain amplifier with good common mode rejection - looking for mV signals on top of a +12V or +48V square wave at PWM frequency.
By using low-side shunts under each half-bridge you don't need the common mode rejection, but you can only measure phase current while the low side FET for that phase is on. That means limiting the PWM duty cycle to ensure that FET is on long enough to measure current, so we trade available voltage range for sample time.
I've also written code to measure all phase voltages with a single low-side current shunt under the whole 3-phase bridge. That requires careful phase shifting of the PWM signals and very fast conversion time, but you don't have to compromise available voltage range 0-100 percent duty cycle is possible.
Typically we run the control loop at PWM frequency, but the measurements need to be faster than that.
Field-oriented Control schemes modulate phase currents at high frequency; the feedback loop must be much faster than the motor phases. Until fairly recently, this stuff was the exclusive province of dedicated ICs (Trinamic et al.) and FPGA. Today, FoC can be done in (mostly) software with MCUs.
The core set of extensions has pretty friendly single letters, but the flip side is you run out of letters pretty quickly.
The non-single-letter extensions should make you feel more at home. Like the supervisor instructions. You have Smcntrpmf which helps with benchmarking by pausing perf counters during traps. I think Smcntrpmf just rolls off the tongue nicely.
Then there's a lot of extensions that start with Z followed by a sprinkling of random letters which is secretly an abbreviation you couldn't have guessed. For instance you have your SHA-2 instructions in Zvknha and Zvknhb, since that's the Vector Krypto NIST Hashes.
I see you are unfamiliar with `rv64mafdcbvh_zicsr_zicntr_zihpm_ziccif_ziccrse_ziccrse_ziccamoa_zicclsm_za64rs_zihintpause_zic64b_zicbom_zicbop_zicboz_zfhmin_zkt_zihintntl_zicond_zimop_zcmop_zcb_zfa_zawrs_supm_svade_ssccptr_sstvecd_sstvala_sscounterenw_svpbmt_svinval_svnapot_sstc_sscofpmf_ssnpm_ssu64xl_sstateen_shcounterenw_shvstvala_shtvala_shvstvecd_shvsatpa_shgatpa` also known as `RVA23`
I've been building hobby LED art projects with WLED (exclusively built on the ESP32 platform). It's been a blast. These little boards are so powerful and the open source community continues to amaze me.
My preferred controller platform is of the QuinLED line - comes with power distribution, voltage regulators, fat copper lines, configurable data-line resistors, and smart auxiliary hardware support all for an affordable $30-$50 per controller. (quinled.info)
<https://kno.wled.ge/> - WLED homepage and probably my favorite clever URL of all time.
The specs look great, will see how long it takes to get these as WROOM modules or on little dev boards; my two form factors of choice for Espressif devices. I'm also curious about the pricing, so far they've impressed me with how much more you get in successive generations at a similar price.
Not "just", it's (presumably) 8 dedicated pins that form an RMII interface. This is not the same 8 pins as you'll find in your 4-pair Ethernet cable, it's a separate protocol which can be connected to an Ethernet PHY transciever like a TI DP83867E [1], which is further connected to "magnetics" [2], a convenient package of 8 integrated transformers and chokes that provide the galvanic isolation feature of an Ethernet connection.
A few SoCs provide integrated PHY transceivers, but usually it's an external chip.
> I'm interested in audio out because I dabble in musical instruments.
Sorry, I don't know. I'm just responding to echo and expand on another reply that Bluetooth for anything related to serious music, from audio playback to MIDI input is a dumpster fire on Windows.
Several years ago I tried to set up a high-end Windows laptop for hobby DAW composition on the go. The real-world BT audio latency just from laptop to headphones/earbuds was unworkable and, separately, the input latency from BT midi controllers was unworkable. Stacked together the total lag was laughable.
At the time, the issues were widely known and much lamented. Some tech blogs (including one at MSFT) indicated there were issues at every level of the stack (drivers, firmware, silicon) and work was proceeding to address the end to end shit show. The only workable Windows solutions referenced online involved using specific non-Bluetooth wireless devices. Needing to have a dedicated USB dongle hanging off the laptop combined with having a choice of either one specific device or a receiver dongle to support all devices, is less appealing than just having a wire.
Since then I've looked again every year or so but have seen no reports yet of meaningful progress and there's even less discussion of work in progress. Very disappointing. And the situation on the BT audio quality side doesn't seem much better. If you don't want degraded audio quality it's either choosing very specific devices which support a proprietary BT codec or switching to non-BT wireless dongle hardware. At least there is talk of improvement on audio quality but no clear indication better baseline minimum audio quality will ever be mandated in the BT audio standard.
If anyone has info the baseline latency or quality (input or output) of standard BT devices in Windows configs will improve, I'd be delighted to hear it.
Low latency in Bluetooth audio comes down to codecs and the best are proprietary.
If you want to really cut down latency and need wireless with hardware like this, you could use a second ESP32 and send your own bitstream between them.
Is there any reason you want wireless? Bluetooth audio is a disaster, AFAIK. You don't want to use it for music. Just go wired, the ether is too cramped already.
This looks like the long-awaited replacement for the original ESP32. The S and C series have been relatively low performance (the S better than the C but stuck on the outgoing Xtensa architecture), the P4 is powerful but lacks wireless. This is a relatively high performance, dual core MCU with wireless; a nice default option for low volume designs where being able to copy a previous implementation is more important than saving a few cents. Just like the ESP32. Nice.
I was wondering this as well. What exactly makes this a good AI chip vs others.
Unless they're not listing a major feature in their spec, a dual core 320Mhz microcontroller is not bad but youre not going to be running any kind of vision model on it, at least very fast.
I'm excited that this MCU and the P4 has RISC-V CLIC. That puts it at least on par with Cortex NVIC and enables bare metal frameworks like Rust RTIC to work really well.
Also 4x MCPWM peripherals; that's a first for any Espressif MCU.
The additional GPIOs are very welcome as well. CAN-FD!
This device is going to be a big hit for Espressif.
How do I order a few samples, seem like there is a MOQ ?
Also I want to dive into hardware stuff but I'm always clueless as to what I do afterwards when this would arrive? Are you using a generic board or are you ordering and designing PCBs to hook this up to?
What are you using it for ? How do I go from a prototype to mass production via kickstarter?
Typically you look for a development board with the chip embedded on it. The dev board will have a usbc port and multiple pins that can be routed to LEDs, miniscreens, audio devices, etc. To program it you can usually use Lua (a very simple embedded language, almost JS-like) or you can use C/Rust/Zig as well. Arduino IDE works for it, too. You code from desktop and upload ROMs via USBC.
You can plug the dev board into sandwich board for easier prototyping. To go to mass production, you'll need to hand off your prototype spec to a custom PCB maker that you can order from, prices vary a lot based on volume and some shops specialize in low volume for early products.
Your end product should basically be a circuit board, case, battery, and any external components like LEDs or screens, then you assemble with plugs or wiring/soldering.
It is sometimes possible to make a product from the dev boards, especially the small ones, but your product still has to get a custom FCC certification (not a deal breaker, just a hoop to jump through), whether using dev board or custom.
As I understand it, Z-Wave is substantially more closed/proprietary. Both Thread and Zigbee are protocols that run on top of 802.15.4, which Espressif already has in other products.
I think Z-Wave is a bit more open now but everything I’m seeing indicates Zigbee has pretty thoroughly killed it by not requiring arduous certification processes and being generally easier to work with. Z-Wave is technically superior with the ability to have devices directly communicate with each other for basic functionality but at least for me that wasn’t worth the massive markup and I’m slowly replacing anything z-wave with Zigbee equivalents.
S has never implied Xtensa, and C doesn't imply RISC-V. That's a widely held misunderstanding. S, C, P, etc. are product categories. S devices are high performance SoCs; large feature set, high frequency, not the lowest power or cost.
And even if you don't need WiFi + BLE for a particular project, you may need it for other projects, and it might have value for you to standardise on one ecosystem.
Theoretically, yeah. Though at 320Mhz, with only 2.4ghz wireless, even with two cores, I doubt it's going to get anywhere near the throughput to fill the gigabit connection.
I kind of wish these all weren't called ESP32. ESP8266 and ESP8285 -> ESP32 made sense, but now we have 10+ different versions with different features and different architectures.
Kind of like how in every thread involving a Raspberry Pi Pico (RP2030/RP2350), there's always someone confusing it with the single board computer version.
The ESP32 (Classic, usually WROOM-32E) is still usually what comes to mind when I hear ESP32.
It signals ESP-IDF compatibility
But it's the same scheme as STM32, EFM32, GD32, …
Espressif is on fire! And the CPU even has SIMD instructions!
RISC-V cores is a big deal for embedded systems because now compiling for SoCs is only a matter of `rustup target add riscv32imac-unknown-none-elf` instead of downloading half-broken proprietary toolchains and SDKs.
Take a look at https://kerkour.com/introduction-to-embedded-development-wit... and https://kerkour.com/rust-esp32-pentest to get started with modern (Rust ;) embedded development.
>> And the CPU even has SIMD instructions!
Yes, but it looks like there is no hardware floating point. The description of the CORDIC module indicates fixed-point calculations, which is consistent with the lack of any reference to floating point.
I am happy the have CAN-FD and Motor PWM module, but nowhere did I see conversion times listed for the ADC. For motor control I demand 1uS conversion time or less, and in the last year I've switched from fixed point to floating point after holding off on that switch for ~15 years.
From the ESP32-S31 datasheet: "Single-precision floating-point unit (FPU) per core"
The datasheet apparently doesn't say, but judging by their other products' listed 12 bit SAR ADC sampling rates (and assuming this one is similar to what appears to be their standard ADC ) the conversion time will be on the order of 10uS.
Also why do you need 1uS for motor control? 1uS is 0.1 degrees of rotation at 16,666 RPM if I did the math right.
I don't know much about motor control, is it normal to need that fast of feedback?
>> Also why do you need 1uS for motor control?
It's not that important if you use current sensors on the motor phases. But then you're looking at HALL sensors or a shunt with a very high gain amplifier with good common mode rejection - looking for mV signals on top of a +12V or +48V square wave at PWM frequency.
By using low-side shunts under each half-bridge you don't need the common mode rejection, but you can only measure phase current while the low side FET for that phase is on. That means limiting the PWM duty cycle to ensure that FET is on long enough to measure current, so we trade available voltage range for sample time.
I've also written code to measure all phase voltages with a single low-side current shunt under the whole 3-phase bridge. That requires careful phase shifting of the PWM signals and very fast conversion time, but you don't have to compromise available voltage range 0-100 percent duty cycle is possible.
Typically we run the control loop at PWM frequency, but the measurements need to be faster than that.
Field-oriented Control schemes modulate phase currents at high frequency; the feedback loop must be much faster than the motor phases. Until fairly recently, this stuff was the exclusive province of dedicated ICs (Trinamic et al.) and FPGA. Today, FoC can be done in (mostly) software with MCUs.
People will always find a reason to complain or pretend they are controlling rocket motor servos with their ESP32
where did you find cordic mention?
Nice. Been meaning to try rust on these sort of devices but the riscv I saw thus far seemed to be mixed arm and riscv which seemed weird
Curious: What does the "imac" stand for in the architecture target name ?
IMAC are the RISC-V extensions supported:
I = Base integer instruction set, 32-bit
M = Standard extension for integer multiplication and division
A = Standard extension for atomic instructions
C = Standard extension for compressed instructions
https://en.wikipedia.org/wiki/RISC-V#ISA_base_and_extensions
Thanks.I can't believe they chose non-arcane, memory-friendly letters. Kind of rare in naming hardware I feel (unless it's not ?)
The core set of extensions has pretty friendly single letters, but the flip side is you run out of letters pretty quickly.
The non-single-letter extensions should make you feel more at home. Like the supervisor instructions. You have Smcntrpmf which helps with benchmarking by pausing perf counters during traps. I think Smcntrpmf just rolls off the tongue nicely.
Then there's a lot of extensions that start with Z followed by a sprinkling of random letters which is secretly an abbreviation you couldn't have guessed. For instance you have your SHA-2 instructions in Zvknha and Zvknhb, since that's the Vector Krypto NIST Hashes.
I see you are unfamiliar with `rv64mafdcbvh_zicsr_zicntr_zihpm_ziccif_ziccrse_ziccrse_ziccamoa_zicclsm_za64rs_zihintpause_zic64b_zicbom_zicbop_zicboz_zfhmin_zkt_zihintntl_zicond_zimop_zcmop_zcb_zfa_zawrs_supm_svade_ssccptr_sstvecd_sstvala_sscounterenw_svpbmt_svinval_svnapot_sstc_sscofpmf_ssnpm_ssu64xl_sstateen_shcounterenw_shvstvala_shtvala_shvstvecd_shvsatpa_shgatpa` also known as `RVA23`
There are a few lettered extensions to the base RV32I instruction set. e.g.:
* https://docs.riscv.org/reference/isa/unpriv/m-st-ext.html
where did you find it?
very interesting, do you have a pointer with more info on what kind of SIMD support it has?
Hopefully comparable or better than ESP32S3.
But with the weird alignment thing fixed
I've been building hobby LED art projects with WLED (exclusively built on the ESP32 platform). It's been a blast. These little boards are so powerful and the open source community continues to amaze me.
My preferred controller platform is of the QuinLED line - comes with power distribution, voltage regulators, fat copper lines, configurable data-line resistors, and smart auxiliary hardware support all for an affordable $30-$50 per controller. (quinled.info)
<https://kno.wled.ge/> - WLED homepage and probably my favorite clever URL of all time.
The specs look great, will see how long it takes to get these as WROOM modules or on little dev boards; my two form factors of choice for Espressif devices. I'm also curious about the pricing, so far they've impressed me with how much more you get in successive generations at a similar price.
If you're excited about the (relatively) speedy RISC-V cores and SIMD, look at the P4 which is available now. It has a slightly faster clock but no wireless: https://products.espressif.com/#/product-comparison?names=ES...
There's some cool work out there using the dsp functionality and built in image handling to crunch a lot of pixel data, which should work similarly on the S31: https://www.reddit.com/r/WLED/comments/1ry2jd7/wledmmp4_with...
Previous discussion from two months ago, when this was announced: https://news.ycombinator.com/item?id=47561678
Good to have WiFi and wired ethernet on the same part again.
Although we lost the MIPI support that the P4 dual-core RISC-V line has.
How does wired internet technically work on these chips? Is it just 8 dedicated GPIO pins?
Not "just", it's (presumably) 8 dedicated pins that form an RMII interface. This is not the same 8 pins as you'll find in your 4-pair Ethernet cable, it's a separate protocol which can be connected to an Ethernet PHY transciever like a TI DP83867E [1], which is further connected to "magnetics" [2], a convenient package of 8 integrated transformers and chokes that provide the galvanic isolation feature of an Ethernet connection.
A few SoCs provide integrated PHY transceivers, but usually it's an external chip.
[1]: https://www.ti.com/lit/ds/symlink/dp83867e.pdf
[2]: https://yageogroup.com/content/datasheet/asset/file/DATASHEE...
Looks like you need an external PHY. It can talk to the PHY with RGMII which uses 12 pins, which are muxed with GPIO8-19.
I'm interested in audio out because I dabble in musical instruments.
What's the state of Bluetooth audio out on microcontrollers? Is low latency and high quality output possible?
> I'm interested in audio out because I dabble in musical instruments.
Sorry, I don't know. I'm just responding to echo and expand on another reply that Bluetooth for anything related to serious music, from audio playback to MIDI input is a dumpster fire on Windows.
Several years ago I tried to set up a high-end Windows laptop for hobby DAW composition on the go. The real-world BT audio latency just from laptop to headphones/earbuds was unworkable and, separately, the input latency from BT midi controllers was unworkable. Stacked together the total lag was laughable.
At the time, the issues were widely known and much lamented. Some tech blogs (including one at MSFT) indicated there were issues at every level of the stack (drivers, firmware, silicon) and work was proceeding to address the end to end shit show. The only workable Windows solutions referenced online involved using specific non-Bluetooth wireless devices. Needing to have a dedicated USB dongle hanging off the laptop combined with having a choice of either one specific device or a receiver dongle to support all devices, is less appealing than just having a wire.
Since then I've looked again every year or so but have seen no reports yet of meaningful progress and there's even less discussion of work in progress. Very disappointing. And the situation on the BT audio quality side doesn't seem much better. If you don't want degraded audio quality it's either choosing very specific devices which support a proprietary BT codec or switching to non-BT wireless dongle hardware. At least there is talk of improvement on audio quality but no clear indication better baseline minimum audio quality will ever be mandated in the BT audio standard.
If anyone has info the baseline latency or quality (input or output) of standard BT devices in Windows configs will improve, I'd be delighted to hear it.
Low latency in Bluetooth audio comes down to codecs and the best are proprietary.
If you want to really cut down latency and need wireless with hardware like this, you could use a second ESP32 and send your own bitstream between them.
Is there any reason you want wireless? Bluetooth audio is a disaster, AFAIK. You don't want to use it for music. Just go wired, the ether is too cramped already.
There are alternatives, but being able to use an external amplified speaker and also move around easily would be nice. Maybe it's not feasible yet.
This looks like the long-awaited replacement for the original ESP32. The S and C series have been relatively low performance (the S better than the C but stuck on the outgoing Xtensa architecture), the P4 is powerful but lacks wireless. This is a relatively high performance, dual core MCU with wireless; a nice default option for low volume designs where being able to copy a previous implementation is more important than saving a few cents. Just like the ESP32. Nice.
Can it cope with TLS? The esp32 having a viable TLS stack has been a big win
> ESP32-S31 is particularly well suited for edge AI and machine learning workloads, including neural network inference
Any way to know what kind of performance one could expect running e.g. a depth anything model on there?
I was wondering this as well. What exactly makes this a good AI chip vs others.
Unless they're not listing a major feature in their spec, a dual core 320Mhz microcontroller is not bad but youre not going to be running any kind of vision model on it, at least very fast.
I'm excited that this MCU and the P4 has RISC-V CLIC. That puts it at least on par with Cortex NVIC and enables bare metal frameworks like Rust RTIC to work really well.
Also 4x MCPWM peripherals; that's a first for any Espressif MCU.
The additional GPIOs are very welcome as well. CAN-FD!
This device is going to be a big hit for Espressif.
How do I order a few samples, seem like there is a MOQ ?
Also I want to dive into hardware stuff but I'm always clueless as to what I do afterwards when this would arrive? Are you using a generic board or are you ordering and designing PCBs to hook this up to?
What are you using it for ? How do I go from a prototype to mass production via kickstarter?
Typically you look for a development board with the chip embedded on it. The dev board will have a usbc port and multiple pins that can be routed to LEDs, miniscreens, audio devices, etc. To program it you can usually use Lua (a very simple embedded language, almost JS-like) or you can use C/Rust/Zig as well. Arduino IDE works for it, too. You code from desktop and upload ROMs via USBC.
You can plug the dev board into sandwich board for easier prototyping. To go to mass production, you'll need to hand off your prototype spec to a custom PCB maker that you can order from, prices vary a lot based on volume and some shops specialize in low volume for early products.
Your end product should basically be a circuit board, case, battery, and any external components like LEDs or screens, then you assemble with plugs or wiring/soldering.
It is sometimes possible to make a product from the dev boards, especially the small ones, but your product still has to get a custom FCC certification (not a deal breaker, just a hoop to jump through), whether using dev board or custom.
ty!!!!
Any reason why this device wouldn't have Z-Wave? Is the wireless protocol significantly different than Thread and Zigbee?
As I understand it, Z-Wave is substantially more closed/proprietary. Both Thread and Zigbee are protocols that run on top of 802.15.4, which Espressif already has in other products.
I think Z-Wave is a bit more open now but everything I’m seeing indicates Zigbee has pretty thoroughly killed it by not requiring arduous certification processes and being generally easier to work with. Z-Wave is technically superior with the ability to have devices directly communicate with each other for basic functionality but at least for me that wasn’t worth the massive markup and I’m slowly replacing anything z-wave with Zigbee equivalents.
This device only has a 2.4GHz radio. Z-Wave is sub-1GHz.
I don't know for sure but Bluetooth, WiFi and Zigbee are on the same frequency band. Z-Wave is not.
(at least in the US, not sure about other countries)
It being RISC-V is awesome, but how does it make sense that it's S series when S series have been Xtensa cores? Why is it not C series?
S has never implied Xtensa, and C doesn't imply RISC-V. That's a widely held misunderstanding. S, C, P, etc. are product categories. S devices are high performance SoCs; large feature set, high frequency, not the lowest power or cost.
Is anyone else worried that these chips are all made in China?
For what its worth, Espressif chips are open source, but yes, I wouldn't run national security or government devices on these.
> Espressif chips are open source
No they're not? Anyway I assume GP was asking due to procurement concerns, not security.
I wish Espressif was an American company and publicly traded. I'd invest heavily. I have nothing but good things to say about their products.
Their product naming could be better, since S3 is going to show S31 in the search results.
This looks like a nucleo144, except its risc-v... but why would I use it over said nucleo144?
Better connectivity. The Nucleo 144 only has 100mbit ethernet, as far as I can tell, but the new ESP chip has gigabit, along with wireless.
WiFi+BLE?
And even if you don't need WiFi + BLE for a particular project, you may need it for other projects, and it might have value for you to standardise on one ecosystem.
When can we buy these?
The dev boards are already up for sale. I'm personally looking forward to the modules being stocked on LCSC, no idea when though.
> The dev boards are already up for sale.
I didn't expect to see that for a while yet. Not the usual Espressif announce and wait a year+ pattern.
Love to see more RISC-V in the wild
The 1GB bandwidth is interesting. It also has Simd instructions too.
Could this theoretically be used as a router or wireguard vpn instance?
Theoretically, yeah. Though at 320Mhz, with only 2.4ghz wireless, even with two cores, I doubt it's going to get anywhere near the throughput to fill the gigabit connection.
Yeah, I’m not entirely sure what use cases there are which include both an ESP32 and gigabit networking.