Comment by kreelman
2 hours ago
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
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).
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)