Don't forget the 128 bit vector ISA with 32 registers, supporting up to 64 bit int and FP, and with LMUL=8 you can process 1024 bits with a single instruction (at 3 cycles per 128 bits for most operations). Fully supported by GCC and CLANG (xTHeadVector) and compatible with RVV 1.0 with just a command line switch if you use the C intrinsic functions. (a lot of code working on 8 bit elements is binary compatible with RVV 1.0 too e.g. typical memcpy(), memset(), memcmp(), strlen(), strcpy(), strcmp())
When I bought my 64 MB Duo they were $3!
Then for a long time they were $5 for the 64 MB, $7 for the 256 MB, and $10 for the 512 MB.
Sadly, like everything else, they've gone up considerably this year.
The wild thing is that this SoC is a heterogenous compute device. It has three different kinds of cores: a pretty beefy arm64 core and two different RISC-V cores: a 1Ghz one for running Linux and a 700Mhz one dedicated to running a real-time operating system. The arm64 core can also run its own OS.
Also a user-programmable 300 MHz 8051 (8 bit) primarily there to manage timers and interrupts and wake up the big 64 bit cores.
Note that the application-processor 1 GHz C906 and Arm A53 are either/or, you can't run both at the same time — similar to the Arm M33 and RISC-V Hazard3 core pairs on the Raspberry Pi RP2350.
You can buy sub-$0.50 microcontrollers. But even at $5, I don't know why you'd want to run models on them, it's an environment constrained to the point of being useless for this task.
And I hope it stays that way, I don't want MCU shortages...
Many artificial environments are useless to tasks they were not designed for until somebody experiments, tests, redesigns, and iterates.
I'll give a specific example apropos of TFA. Computer vision models were never run on MCUs because they were constrained to the point of being useless for this task, but then someone tried the impractical, and now it's trivial[1]
Regarding MCU shortages, you should be worried about the supply chain, but I don't see the impact really being from running LLMs on ESP-32s, of all things.
Fun and learning is a really good reason. It also reminds me of the damascene: trying to achieve something that doesn't feel possible, and working through all the extreme resource-constrained engineering limits.
I think most of my embedded projects aren't that useful, but they've taught me a lot.
I'm not disagreeing with you, I think this goes beyond impractical, it's doomed from the get go.
In my book, impractical means "I built a cuckoo wristwatch". Beyond impractical: "I built a cuckoo wristwatch but there was no room for a working mechanism".
I don't see the relationship between "fun and learning" and "(beyond) impractical".
I enter most of my learning project from the assumption that I could just buy/install whatever I am building and save time/money.
Please consider seeing things from a different perspective than "your book".
Not saying this to antagonise you, but because a lot of time reading comments like this makes other posters less willing to share their impractical efforts, and would love to read more of those, not less.
How is it useless? If it has an NPU it is literally built to run models.
You're just extremely biased in what you consider to be a useful ML model. For example, for some strange reason you think only LLMs exist. The model must be as big as possible or else it is pointless.
Training custom non-LLM models for specific tasks so they run on a resource constrained device? You must be insane.
There's a neat project out there that can read your water meter into home assistant using an ESP32+camera+computer vision. I imagine a small TPU like this could be very useful for similar projects. More compute means higher resolutions and more reliability.
Well, that's sub-$0.50. But yeah, CH32V003 is in that ballpark, and some of the cheapest Microchip and Infineon products are around $0.20.
It's almost never worth it to buy the cheapest chip unless you're making a million of something, but there are very good ones around $1-$2, and $5 is the upscale stuff.
Dave "EEVblog" Jones did a review of a (then) $0.03 microcontroller (Padauk) a while back (sorry, I don't know the exact episode).
Iirc an important caveat was that it was a one-time programmable (OTP) part. So you buy a bunch of them, programming failure or firmware-under-test doesn't work? -> toss the part. Of course that isn't an issue for a $0.03 part. But it can be an issue in terms of a board you want it on. Either that means discarding (breakout) boards too, or for development you'd need some kind of adapter to put bare ICs in.
Such annoyances only make sense for high-volume, low cost applications. Which is eactly where parts like that go in.
looks like Padauk PMS150C is back up to 0.08$, oh well :(
it's fun reading all the reactions to it (like "it’s cheaper to program a Padauk PMS150C to be a logic-level converter than to just buy a logic level converter"), but the magic is gone more-or-less
I think that is pretty ungenerous. Before ARM, ISAs were not a commodity, and there were only closed, proprietary implementations of them (usually from a single vendor). Arm licensing its IP and actual designs was hugely beneficial for the broader ecosystem and led to their prevalence in the embedded space. The toolchain and software network effect made it a no-brainer to either reach for a completed Arm design, contract a customized one, or build your own.
The arm experiment ran its course though; the power one vendor had in the marketplace started to be abused for the benefit of the IP holder and detriment to others. Now RISC-V is going one step further with a completely open ISA and also completely open designs. This is an excellent development in the nick of time.
I wonder how Apple feels about arm64 and RISC-V now. They could have probably bought ARM at any point but maybe never considered it to avoid anti-monopoly blowback.
When I bought my 64 MB Duo they were $3!
Then for a long time they were $5 for the 64 MB, $7 for the 256 MB, and $10 for the 512 MB.
Sadly, like everything else, they've gone up considerably this year.
https://arace.tech/products/milk-v-duo
https://arace.tech/products/milkv-duo-s