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Comment by kreelman | Hacker News Reader

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.

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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!

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