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Has anyone here played with any of the RISC-V micros?

Chuck(G)

Chuck(G)

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Visited AliExpress to get something and discovered that a ten-cent RISC-V MCU mounted on a small PCB was only about $3 shipped. Just downloaded the toolchain. I'm interested in comparing it against the ARM-3 and -4 MCUs.
 
One easily gets lost in the swirl of micro controllers hitting the market. And I am quite lost. I'm still contemplating whether I should buy the TI Laumchpad. It still 7 bucks?
 
I've been using the WCH CH32V305 as a keyboard controller. They sell it on a breakout board for $6 on Tindie or AliExpress.

I had designed a custom keyboard that used a Teensy++, but that's discontinued, so I redesigned it to use this. At the time I started it, a lot of the cheap ARM alternatives (Raspi Pico, Black Pill) were a little short on GPIOs if you wanted to make a comically large keyboard.

However, this meant writing firmware since "ready-to-use" firmwares like QMK tended to be AVR or maybe specific-ARM-chips only. But their example codebase had some stuff that could be extended into a full-fat project. (https://gitlab.com/hakfoo1/ch32v-keyboard)

I suspect that the increased horsepower hides a lot of sins in my code.
 
I've been pretty underwhelmed by RISC-V so far. It seems like a lot of sizzle and not a lot of steak. I got one of the Clockwork Pis with an Allwinner D1 and while I like the unit and the form factor, the CPU was working pretty hard to do even basic tasks. I'm sure SiFive units are better and I've seen them make a somewhat credible desktop machine, but SiFive appears to be having some management problems. For my money the only place the architecture is doing well in is custom one-offs and the "too cheap for MIPS" market segment.

Overall it just seems there are better options right now. I'm a Power ISA bigot already, but if you really want a fully libre machine and you have the bucks, you should buy a POWER9. Otherwise, for SBC projects myself I think I'll stick to RPis and other ARM-based units for the time being.
 
@ClassicHasClass, I'm mostly concerned with MCUs for peripheral manipulation.

I've been using the ST Micro STM32F407, 405 and 429 and the F767. No shortage of I/Os there.

I suspect that RISC-V, being royalty-free will gradually displace a lot of the ARM3 and ARM4 MCUs. As far as documentation, consider the reference manual for the STM32F7--it's what 1200 pages? I don't know how to classify that.

I haven't looked over the range of offerings, but I suspect that some vendors will go with ARM peripherals that they already have and drop a RISC-V core into it.

It's good to know that someone's using the RISC-V MCUs.
 
That reminds me. An ebay vendor has hundreds of nos n80188 plcc's for $5. I ordered some a while ago. Need to stock up yet.
 
So, just the plain NMOS ones. Lots of 80C188s on ePay too, some 25MHz ones. And a few 80C188EBs in PLCC 84. The latter are pretty interesting, integrating a bunch of peripherals, but lacking a DMAC. The 80c188EC is pretty close to a PC-on-a-chip but only available in 100 pin QFP.
 
Not that I know of. All I know is it was available in a ceramic leadless package, therefore a possible upgrade for various 80s boxen. Dom't think any or many othera were. Also ran up to 25mhz at least.
 
I have the CH32V003/203 developers kit which is probably what you're talking about. Have done some tinkering with the StarFive board too.
 
Yup, I guess, being of the Seymour Cray school, was programming RISC before it was called that. It seems that the discussions that you posted are all wrapped up in how something is done in C or another HLL. At any rate, RISC-V doesn't seem very "RISC-y" to me.
There's a YT video (somewhere) of a fellow comparing the performance of a RISC-V MCU with a nearly identical (storage and peripherals) ARM version of the same chip. I'll be the first to admit that the compiler for the RISC-V version is probably a lot less mature, but the difference in performance (RISC-V suffers badly in comparison) is definitely a significant data point.
I wonder if RISC-V will endure or if it will meet the same fate as MIPS (one ISA that I really liked).
 
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