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> RiscV is going to win despite its limitations, simply because they can be worked around freely, and the cost per core is zero.

This feels right to me. I've worked on embedded systems and OS my whole career and it just doesn't really feel like riscv wins or loses on technical merit to me.

Boots-on-the-ground engineers might grumble but the decisions that matter here just aren't made by them. Otherwise why would we still be using x86 so much?

I've worked on platforms that had barely-functional CPUs, we had to regularly be in touch with the engs that implemented them and they'd regularly go "oh yeah you've found a bug in our memory subsystem". This was kinda annoying for us but those CPUs were cheap as fuck and that opened up business models that weren't otherwise available. This is always gonna be more important than "ah but the CPUs are suboptimal!!"

We use x86 because the implementations are fast and there's so much software encoded with it. This makes up for the problems of the design. RISC-V doesn't have either of those advantages, though.

Yeah my x86 comment wasn't meant to suggest RISCV can easily beat x86 it was pointing out that "being a good arch" is very low on the list of priorities for making the arch successful.

Exactly as you say, x86 is successful coz there are really good x86 CPUs and a SW ecosystem. Not because it's a good arch. Similarly I think, if it wins, RISCV will win because there's enough demand for a nonproprietary ISA, and this trumps basically everything else.

Another way to say this: I've seen internal slide decks about ISA strategy that target C-suites at megacorps. Not once do those slide decks ever go into technical dis/advantages, coz the people steering the 9-figure investments don't give a shit. If you piped up in those meetings and said "RISCV sucks though!!!" you would just be ignored and not invited back.

It's not really any different from startups. Tech stacks matter but there's a huge number of successful companies out there running total garbage and who knows how many perfectly engineered products go out of business every day coz the thing they perfectly engineered was not useful.

You're agreeing with the conclusion the original article makes:

> None of this is to say that RISC-V is doomed. As I said, I fully expect it to take over the space currently occupied by 8051 as a typical cheap embedded core instantiated when some small amount of logic is needed, or some beefy accelerator or DMA engine needs some mild babysitting. Much like the linux kernel -- the price is right. ARM wants licensing fees, while the RISC-V spec is free, and (this part is key) there are cores out there which can be licensed for free. For situations where performance is not a factor and price is, RISC-V will win simply due to its price. "Good-enough" is a low bar in this case, and RISC-V is of the right height to meet it. And look, this market is not glorious, but it matters and it needs new blood. However, it is important that RISC-V not accidentally think it was chosen for being good. It needs to internalize that it was chosen for being cheap. This is not meant as an insult to cheap small cores -- I've written plenty of assembly for all sorts of shitty cores with shittily designed ISAs. RISC-V is an improvement over PIC and 8051, as little of a compliment as that is.

RISC-V may be suboptimal, but it's a lot better than 8051 and you can use GCC instead of having to buy Keil licenses for all your developers. Meanwhile at the higher end (desktops and higher-end SBCs), you'll still have to pay for a quality out-of-order core even if the ISA is free, and you have to deal with binary compatibility being more important. I can see RISC-V being a massive success on the low end, and displace 8051 and maybe Cortex-M0. However, I don't think this means that it'll be able to displace ARM64 on the high end.

Can you list the actual chips you’re referring to and additional sources to follow? I’ve finally started playing with ESP32 and recently getting curious about the smallest possible things out there. Also

Here's the CH32v003, https://github.com/openwch/ch32v003 These are pretty low end and are fairly available at low cost. Here's a youtube of someone talking through some of the the CH32 boards, https://www.youtube.com/watch?v=Kss6WQvJbRs

He talks about them being the "10c/chip" chip.

Then, there is the CH32v303 https://www.wch-ic.com/products/CH32V303.html, which is the lower end of the chips that support minimal floating point and USB host/client. These ones are a bit more pricey, https://www.lcsc.com/product-detail/C5456849.html at $US1.72 each. The extra price is QFP64 (64 pins, quad flat pack) and more features on the chip, USB, CAN, V4F extension giving one instruction multiply and some floating point operations.

Note that the fact that this chip uses an extension, V4F, for floating point (I think?) is part of the argument of Dmitry's piece on the RISC-V. The chip is pretty low price for a fair bit of power.

CH32v303 costs more than much more capable ARM based RP2354A

And on the RP2354 you can swap one or both ARM cores for RISC-V cores at boot.

I think the CH32v303's single V4F core might be slightly more capable than the Hazard 3 cores RISC-V cores (as it has a hardware FPU), but for everything else the RP2354 is probably better (and the ARM cores do have hardware FPUs)

I feel like the Raspberry Pi products are inherently a special case.

They're probably produced in far greater numbers than most off-the-shelf STM32 or CH32V chips. You've got a huge ready market in hobbyist/educational products as well as the commercial products that have used it as a convenient choice.

There's that whole non-profit/educational heritage around them that likely selects for a different set of defaults and features than, say, a MCU designed specifically to be the controller for a SATA SSD or a $19 Roku clone.

They also have a small product range, as compared to the broad product matrix a lot of the more "commercial brand" MCUs come in. I know even the CH32v30x chips come in several variations multiplied by several package options (which vary enough to impact the features you can realistically use on them).

> They're probably produced in far greater numbers than most off-the-shelf STM32 or CH32V chips.

I highly doubt it. The RP2xxx lacks the built-in functionality for use in, say, a car, and it isn't cheap and fully-integrated enough for dime-a-dozen gadget application. They are great for hobbyists due to their low barrier to entry, but there really isn't a niche they serve when it comes to mass-produced electronics.

> They are great for hobbyists due to their low barrier to entry, but there really isn't a niche they serve when it comes to mass-produced electronics.

This.

Just programming a microcontroller is generally a pain, but a pain that hardware manufacturers can deal with, because they have employees with experience, who can read the long datasheets, get proper programmers and run the manufacturers software packages to program everything.

For hobbyists, you're basically limited to arduinos, esp??/??, and rpi picos, only those are guaranteed to have a lot of software support, documentation, easy availability on aliexpress etc. for cheap, and can be made to actually do some stuff in an afternoon of tinkering.

(technically it's the same with proper RPis, where they're the only SBC board (not x86 baed) that you're guaranteed will have at least some software support after 5+ years).

> technically it's the same with proper RPis, where they're the only SBC board (not x86 baed) that you're guaranteed will have at least some software support after 5+ years

This isn't quite true, though it's true at the RPi's price point. For example, Toradex (disclosure: I work for Toradex) produces the colibri-imx6 system-on-module that can be turned into an SBC with a stock carrier board. It was introduced in 2014, continues to be supported today, and will continue to be supported until 2036. But that level of long-term support and maintenance costs money, and the pricing reflects that.

This is often a gilded cage. Think about it. On one hand Great, you dont have to redesign your SBC, that would take whole ~1-2 engineering man months (small simple SBC at not bureaucratic nightmare small to middle size company, obviously man hours go thru the window at big many cook orgs). On the other hand you keep shipping SLOW AS ASS SBC to your customers while Chinese competition keeps redesigning _every year_ and offers smoother UI experience with more features for less money.

The real thing manufactures do is ensure that the SBC is available as long as they want it. My company started an embedded controller 6 years ago, at that time we got a contract from manufactures that all the parts would be available for 12 years, thus ensuring we won't have to redo that controller for 3-4 more years (and we might just renew the contracts). As a hobbyist you don't have that guarantee (except the 3 you named) it happens all too often you buy something only to discover not enough other hobbyists have the same board to give it a critical mass of people to make it work. It can still work, but you will personally have to do all the work to make it keep running which few hobbyists have the time/energy for (and often the deep technical knowledge is lacking as well)

A big part of the numbers game is on variants though. There's what, eight or ten total RP2040/2350/2354 parts to choose from? So all the volume is split between those.

Conversely, there are a lot more variations within other MCU lineups. Just looking at the WCH CH32v30x datasheet-- a single relatively low-popularity range from a single vendor, the datasheet shows 9 basic models with five different physical form factors, and there are theoretically different SKUs for different temperature ranges, etc.

The "much more capable" is debatable. The RP2000 series is quite disappointing IO-wise: no timers, barely any ADC, no touch sensors, no CAN, bare minimum of USART/I2C/SPI, no I2S, no I3C, no ethernet, no USB PD...

And yeah, it has its PIO modules, but those aren't powerful enough to make up for it. They are fine as an alternative to bitbanging Neopixels, but you can't rely on some hobbyist's vibe-coded weekend PIO project which takes up all the PIO slices and 30% of one core to do application-critical communications.

I would take an RP2000 in a heartbeat for most of my hobbyist products, but for anything professional an STM32 is orders of magnitudes better, and even a CH32v303 looks like a more attractive option at first glance.

RPi is not less expensive; current Qty 1 lcsc price for rp2354b is $1.62, whereas ch32v303 is $0.88

thank you!

8 dollar linux computers were a thing before riscv as well btw, i remember buying 50 chip computers (9$ at the time) for my university linux users group.

    > And also, the first application capable chip you can actually trust to be free of unpublished capabilities.

I am not in the embedded space. Can you explain your thinking behind this comment?

It's widely suspected that the Intel management engine[0] and their equivalents are NSA backdoors

[0] https://www.eff.org/deeplinks/2017/05/intels-management-engi...

Subtly tainted RNGs, flash download backdoors, interfaces that allow covert JTAG are all “features” that can be found in some widely used chips. Because of the freedom of the riscV license, we have microscope inspectable processors being launched by tiny companies that are focused on security and privacy. https://baochip.com/