
A tiny RISC-V MCU board selling for $3 - childintime
https://www.cnx-software.com/2020/01/02/polos-gd32v-alef-tiny-risc-v-mcu-board/
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kken
As already noted in the comments under the linked article: This device is
currently seriously lacking software support, bordering on making it unusable.

It's interesting to note that the company that developed the chip (Gigadevice)
initially got big by copying microcontrollers by ST microelectronics. This
went as far as copying the entire product portfolio including naming scheme
and marketing strategy. (Personally I find this absolutely appalling)

I guess not having to develop a software toolchain for their devices provided
a huge benefit for them. Now that they have a device that cannot rely on
external tools, things look a bit more difficult...

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kragen
I'd been wondering if the GD32F107 was a clone of the STM32F107! Thank you for
confirming that! But surely you can't honestly think that ST microcontrollers
are a reasonable alternative for most electronics manufacturers? As far as I
can tell, ST doesn't even offer datasheets in Chinese!

I think RISC-V software support will probably take shape pretty quickly, in
the next $smallinteger years.

In terms of the ethics of cloning products from other companies, such as
Linux, Chrome, Intel’s 64-bit chips, and Google Search: do you want the future
to be dominated by engineers who create new things, or by owners of
government-granted monopolies like copyrights, patents, and RF spectrum? Bram
Cohen and Richard Stallman, or the RIAA and Verizon?

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makomk
ST's microcontrollers were really popular in Chinese-designed electronics
before GigaDevices cloned them, and the STM32F103 - which is the one they
initially cloned - was especially so. Its popularity in China is almost
certainly why they decided to clone it in the first place.

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kragen
Sure, when you're desperate for decent parts, it makes sense to use overseas
suppliers with long lead times and customer service and datasheets all in
English. And the STM32 line is really great. But if you can instead use a
domestic supplier who speaks Chinese and can get you parts in a few hours
instead of a month, why wouldn't you?

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spurdoman77
These boards are very cool, and I would happily play with them if I had time.
However one thing is a bit mystery to me, what are the use cases more
professionally? Obviously there must be lots of non-hobbyist demand for boards
like this.

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nrp
Typically, boards like this would only be used for prototyping. It's a dead
simple system and there is basically nothing of value in the board itself for
production use. Any design using the same microcontroller would just
incorporate it directly rather than integrating an extra board. That differs
from more complex boards like an RPi Compute Module or an RF module. On those,
you might take advantage of the existing high-layer-count board attached to a
simpler, low-layer-count board, avoid needing to redesign systems that have
signal integrity or RF challenges, or utilize existing certifications around
emissions.

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penagwin
> or utilize existing certifications around emissions.

This is one of the biggest reasons for an extra board for RF modules. RF is
black magic where you REALLY need to know what you're doing to develop your
own board, and if it's not in an already certified module then you have to
have your product pass FCC certifications (costing a lot of money)

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dfox
Very often even the layer count is an issue. For perfect example see almost
any brand name japanese AV DVD/DVR combo which has giant single layer board
with only passives, connectors and links which holds small subboard with
bunchs of (fc)BGAs and somewhat incredible layer count.

On the other hand for small scale devices not only certification comes into
play but also availability and cost. There are niche devices that simply use
some Arduino-ish board as a component, because the board is easier to source
and, more importantly, cheaper than the MCU on it, personaly I view that as
bad design and good reason to use some non-AVR MCU, but that is how it is.

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brianolson
It's early in its life cycle and needs a JTAG interface to work with now, but
it _could_ be a sweet little Arduino board. Comparable to the TeensyLC but $3
instead of $12. 3.3v 33mA 108Mhz 32k RAM 128k flash.

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makomk
It's probably more closely comparable to the STM32F103-based boards which cost
about the same amount as it but have better software support. This is sort of
a derivative of a clone of that exact microcontrller.

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flingo
There's some pretty cheap blue boards that cost less than the CPU on them, due
to a manufacturing flaw. (one resistor is wrong, so it won't program on most
PCs)

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echoteecat
I've been interested in homebrew computer projects that use a Z80 as the CPU,
I wonder how easily it could be done with a RISC-V cpu.

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dahx4Eev
It would be interesting when ChibiOS supports RISC-V.

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rs23296008n1
Black on green silk screen text is an unlikely choice. Still early days
however so probably fixed in next revision.

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exabrial
We just had an article on HN yesterday saying there were no cheap RISC-V board
available... and here we are!

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Gladdyu
The issue was that there wasn't a cheap riscv board that supported the
privileged section of the ISA (so you can run an OS on it). This, being a
microcontroller, doesn't either.

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freeopinion
The Reference Manual claims "Machine (M) and User (U) Privilege levels
support" on page 22.

Probably not the kind of privileges discussed yesterday.

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Taniwha
yup, for linux you want M/S/U modes at least (kernel runs in S) and page table
table support of course

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p0llard
I was under the impression you could get away with using Machine mode for both
the SBI and the Kernel?

Sv39 paging is the major requirement as you point out.

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Taniwha
Machine mode runs without the MMU, linux really needs an MMU to do kernel
stuff too (including stuff like copyin/copyout)

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nickik
There is actually quite a bit of work going on in Linux without MMU. Check
Linux Plummers conference RISC-V track for example.

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Taniwha
Yeah that's why I said "really needs", there are cut down versions that will
run without an MMU, it's not really the mainline Linux though - I've worked
with MMUless kernels in the past, it's not a lot of fun (and I started porting
V6/V7 for base and bounds swapping machines)

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terrycody
Such boards can be used for emulation retro games?

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Narishma
No. It's a microcontroller board.

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kragen
At least the STM32 and LPCxxxx boards have plenty of horsepower for 80s game
emulation.

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Narishma
You're not going to be doing much emulation with 32 KB of RAM.

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kragen
The Atari had 128 bytes of RAM. Nintendo had 4.3K.

