ESP32-S31(espressif.com)
103 points by volemo 1 hour ago | 15 comments
oritron 25 minutes ago
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...

randomint64 1 hour ago
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.

phkahler 34 minutes ago
>> 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.

polpo 16 minutes ago
From the ESP32-S31 datasheet: "Single-precision floating-point unit (FPU) per core"
NooneAtAll3 26 minutes ago
where did you find cordic mention?
Havoc 17 minutes ago
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
cassepipe 41 minutes ago
Curious: What does the "imac" stand for in the architecture target name ?
mentalpagefault 32 minutes ago
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

cassepipe 12 minutes ago
Thanks.I can't believe they chose non-arcane, memory-friendly letters. Kind of rare in naming hardware I feel (unless it's not ?)
JdeBP 34 minutes ago
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

24 minutes ago
NooneAtAll3 25 minutes ago
where did you find it?
tosh 39 minutes ago
very interesting, do you have a pointer with more info on what kind of SIMD support it has?
bobmcnamara 14 minutes ago
Hopefully comparable or better than ESP32S3.

But with the weird alignment thing fixed

jml7c5 9 minutes ago
Previous discussion from two months ago, when this was announced: https://news.ycombinator.com/item?id=47561678
zuzululu 10 minutes ago
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?

mort96 13 minutes ago
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.
Aurornis 44 minutes ago
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.

tetris11 23 minutes ago
How does wired internet technically work on these chips? Is it just 8 dedicated GPIO pins?
LeifCarrotson 6 minutes ago
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...

BenjiWiebe 5 minutes ago
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.
frikk 37 minutes ago
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.

hart_russell 18 minutes ago
Any reason why this device wouldn't have Z-Wave? Is the wireless protocol significantly different than Thread and Zigbee?
mherkender 13 minutes ago
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)

Aurornis 16 minutes ago
This device only has a 2.4GHz radio. Z-Wave is sub-1GHz.
orphea 13 minutes ago
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?
skybrian 38 minutes ago
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?

oritron 20 minutes ago
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.

tliltocatl 21 minutes ago
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.
skybrian 1 minute ago
There are alternatives, but being able to move around easily would be nice. Maybe it's not feasible yet.
hackingonempty 28 minutes ago
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nubinetwork 19 minutes ago
This looks like a nucleo144, except its risc-v... but why would I use it over said nucleo144?
KZerda 8 minutes ago
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.
bobmcnamara 13 minutes ago
WiFi+BLE?
mort96 9 minutes ago
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.
jeremywho 44 minutes ago
When can we buy these?
Scene_Cast2 40 minutes ago
The dev boards are already up for sale. I'm personally looking forward to the modules being stocked on LCSC, no idea when though.
topspin 24 minutes ago
> 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.

rie_t 1 hour ago
Love to see more RISC-V in the wild
Imustaskforhelp 1 hour ago
The 1GB bandwidth is interesting. It also has Simd instructions too.

Could this theoretically be used as a router or wireguard vpn instance?

KZerda 12 minutes ago
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.
gswdh 34 minutes ago
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