Milk-V Duo is a $9.00 RISC-V tiny embedded computer | Hacker News Reader

Milk-V Duo is a $9.00 RISC-V tiny embedded computer

linuxgizmos.com

69 pointssquarefoot26 comments

Roughly twice the cost an identically-sized RP2040 Pico (both 51mm x 21mm), but 6x clock, with 250x the RAM, miniSD slot, USB-C and optional ethernet connect. Freaking awesome.

(And to show my clock working here: a stock RP2040 is two cores @ 133Mhz each. This board's 1Ghz + 700Mhz. 1700 / 266 = 6.4x. Not sure how apples to oranges arm-thumb/risc-V is though?)

C906 is twice as wide(64 vs 32 bit) and a 128bit vector unit(closer to ARM NEON than M0 in terms of capability).

Dunno about power consumption.

More similar to SVE than NEON, supports both int and FP vectors. One instruction can process 256 / 512 / 1024 bits of vector at a time if you only need 16 / 8 / 4 vector variables (including masks) in your loop, not 32.

Full FPU and MMU, runs standard Linux e.g. Ubuntu server boots with about 36 MB free RAM.

To answer the previous poster, RV64GC is more similar to Thumb2 (but with 32 registers of 64 bits, not 16 registers of 32 bits) than to the cut-down Thumb1 (technically ARMv6-M) in the Pico. Plus, yeah, DP FPU and vector and MMU.

The RP2040 cannot run standard Linux. This can.

Are you kidding me? Even 8-bit microcontrollers can run Linux just fine. https://dmitry.gr/?r=05.Projects&proj=07.%20Linux%20on%208bi...

Really? This is what you call running Linux? From your link:

> All that's left is that pesky 32-bit CPU & MMU requirement. Well the AVR has no MMU and is 8-bit. To conquer this obstacle, I wrote an ARM emulator.

> It takes about 2 hours to boot to bash prompt ("init=/bin/bash" kernel command line). Then 4 more hours to boot up the entire Ubuntu ("exec init" and then login). Starting X takes a lot longer.

Uh, yeah ... I don't think I'd use the verb "run" anywhere near this.

Your comment implies that the RP2040 is incapable of booting Linux, not just that it's slow.

With enough time, you can boot Linux with a pencil and paper. The amount of time needs to be practical, in order to be able to be useful to do stuff. That is maybe what is expected from "runs". Eg, a device can't run Doom if it is unplayably slow.

I understand what was meant now, but my point is that the original comment wasn't clear.

Price plus shipping and taxes; still interesting nonetheless.

Also FTA: > The Wiki pages for this device describes that the “Milk-V Duo includes CV1800B chip with a 100Mbps PHY. PHY is linked to a 5-pin solder pad, Additionally, an external transformer and a RJ45 socket are needed for Ethernet use.”

I don't see the lack of transformer a problem for various reasons. Driving an Ethernet transformer requires some current, and it can be avoided completely when making point to point connections between two boards on the same system, or using switch chips (also without magnetics) to connect more boards in a star scenario such as a small cluster.

There's a bunch of nice chips with onboard ram now. This is yet another one with 64MB.

Ideally I'd love to have at least 512MB of ram. I realize that's overkill for a lot of applications, but it'd give me confidence it can run a reasonably competent Linux userland.

I'm pretty certain 64MB is enough for a tailor made Linux distro. What's most important is for the CPU to have an MMU to manage virtual memory. Otherwise, you're staying in microcontroller flatland where any app can access any address.

64MB was good enough for Black Rhino Linux

Linux has a nommu configuration, no? Obviously no good for security, and it is still flatland, but a flatland running Linux.

64 MB is enough to run full modern Fedora or Ubuntu in "server" mode, ssh in and run emacs, compile smallish programs using gcc.

Try it right here:

https://bellard.org/jslinux/vm.html?cpu=riscv64&url=fedora33...

It's slow the first time as it loads things over the network, but once files are cached in the browser it takes 5 seconds to boot to a shell prompt and 2.5 seconds to gcc compile helloworld.

You can run GNU "screen" to make a couple of panes and run "top" in one and see there is a good amount of free RAM even when running emacs.

This JS emulation runs at around the speed of maybe a 200 MHz CPU. The 1 GHz C906 in the Milk-V Duo is probably about five times faster, and the 480 MHz C910 in the BL808 chip on the M1s and Ox64 is several times faster as well.

Quite usable speed, comparable to the original Raspberry Pi. Just not enough RAM to run a modern GUI is all.

I'd love to be able to bring more of my regular tools with me. Run a small prometheus instance, a small samba instance, a postgres database.

On a 128MB wifi router this all & a lot of other small utils fits okay ish, runs fine, while routing. 256MB vastly preferred.

I have no idea of the needs of prometheus. Samba and postgres should be fine on a machine with more than 32 MB free.

Hell, in the late 90s I was running that kind of stuff on Linux on a Pentium with 32 MB total RAM, not >32 MB free after booting.

It'd all fit barely. But gee it's getting tight. It just feels to me not worth fighting. And I'd want a couple small apps running too, & maybe not small native C things but like some smallish node.js things.

Wifi routers tend to be much bigger class devices but 128mb is very common, 256 pretty establishdd. It's just nice not feeling super space constrainted. This isn't rocket science, we shouldn't have to obsess over payload size. The cost should be so small. Albeit yet at scale some folks do have cause to pinch those pennies, it's not a good general computing path.

SOCs without wifi / bt somehow don’t excite me. I‘d like to see Espressif move up the food chain and make a Pi Zero 2 W competitor. Their new chips are RISCV already, and quite powerful. Only thing thats missing is RAM and MMU.

Agreed, wifi is nice when I want to toss micro systems in remote locations without ethernet. Or even on a battery setup with a camera. Lots of use different uses, for me the future is moving towards wireless, even wireless storage.

For me, it's wired with any technology that gives power and network over the same wire so that I can forget the thing when setup (no wireless issue and connection problem) and it doesn't stop working because your router is down.

More about the soc here: https://riscv.org/blog/2022/06/xuantie-c906-tops-mlperf-tiny...

That's not the same SoC, which didn't exist when that article was written (and can't be bought yet either). It's a different SoC, the Allwinner D1, which uses the same C906 core (but only one of them, not two) and has been shipping on SBCs for two years.

Oops, you're right. More about it here: https://milkv.io/docs/duo/getting-started/cv1800b and https://milkv.io/docs/duo/resources/mmf

This isn't a superior Pi Pico, it's an inferior Pi Zero. It also seems to be horribly documented - no thanks.

Why would there be finished documentation available when the board hasn't shipped, and can't even be pre-ordered yet?

Also, boards with an SoC with a single 1 GHz C906 core have been shipping for two years, and people testing them have found them superior to a Pi Zero (about 15% faster on average). This board has dual 1 GHz C906s, which is obviously better again.

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