does anyone interested in 20 cent RISC-V MCU?

[zepan0]

Hi, we are sipeed team who made the MAIX project (AI on RISC-V)
We decide to make an RISC-V board in $1, which made with 20 cent RISC-V 32bit MCU(maybe with usb).
Does any one interested in it? Do you have some suggestions?

[ataradov]

Do you have specific silicon in mind? Or are you planning on making a new device?

I'm interested in 20 cent MCU on its own, but it all depends on the package and peripheral set. The board would be a nice starting point, but the MCU is the primary thing here.

[OwO]

I would personally be more interested in a big risc-v SoC that can run Linux.

[hamster_nz]

As you most likely guessed, I would be interested in it, but as I am purely a hobbyist who is  interested in the RISC-V architecture I can't see me acquiring more than a few for experimentation.

However, it would be important milestone for the RISC-V platform to have an offering that is price comparable with the ESP32. Although I own a SiFive HiFive1 one board I will only ever own one due to the cost (US$59) and relatively low spec. The K210 is almost there... but not quite.

Also, one of the key things that the current range of low-cost ESP32 modules lack is an efficient LDO for working with battery solutions. The standard 'go-to' LDO of an AMS1117 has a uses ~10mA, but the standard ESP32 sleeps at 70uA, so 99% of the power is wasted when sleeping. When you want a battery or solar powered solution the option of 70mA when  running, and 10mA when asleep is very poor compared to 60mA when running, and 0.1mA when asleep.

If a 32-bit RISC-V, with USB (either on-chip or a separate CH340g) was available in a form factor that is something like the link below, and I had some confidence in deep-sleep performance (1mA or hopefully much better) I would be very interested, it would be a viable option for my tinkering.

https://www.aliexpress.com/item/New-ESP32-Lite-V1-0-0-for-wifi-Module-bluetooth-board-based-ESP-32-esp-32/32841073426.html

One problem I have had with the ESP32 boards is that their footprint changes every 6 months, so I can no longer easily get the boards I was using last year. If only from the outset somebody make room for a battery controller + JST connector, reset/boot switches, SD card, whatever, and freeze the pin-out and outline.

I would far rather pay a few cents more for a slightly larger PCB with more pins broken out (and maybe some do-not-populate parts) than save a few cents but have the footprint keep changing.

Would you be thinking of a controller package that I can work with at home? Or at that price point is the most economical package a must?

[hamster_nz]

Hi, we are sipeed team who made the MAIX project (AI on RISC-V)

Oh, and that project is awesome. I hope has been successful for you.

It is very interesting and exciting hardware, and is the part I show people if they ask what I am tinkering with. It is currently a DSP-based guitar tuner. 

If anybody hasn't seen the $20 kit here's the link:
https://www.seeedstudio.com/Sipeed-M1w-dock-suit-M1w-dock-2-4-inch-LCD-OV2640-K210-Dev-Board-1st-RV64-AI-board-for-Edge-Computing-p-3207.html

[PCB.Wiz]

We decide to make an RISC-V board in $1, which made with 20 cent RISC-V 32bit MCU(maybe with usb).

What does (maybe with usb) mean ? Does that mean USB inside the 20 cent RISC-V, or a USB download bridge added to the board ?
What are the specs of this 20 cent RISC-V 32bit MCU - package/MHz/Vcc/Peripherals/Flash/RAM ??

[lollandster]

For personal projects I'd love a RISC-V alternative to the Cortex-M, but good documentation is a must for me. For professional usage, no interest (but I'm in a high cost, low volume type of business).

[emece67]

.

[zepan0]

more info,  it will be like a clone of stm32, but with RISC-V core, and high-end version will have USBFS.

[NorthGuy]

I think there are lots of people who would be interested in 20 cent MCU with HS USB module, especially RISC-V.

As to the board, even if I bought it, I would never buy more than one or two, so it's not much difference for me personally, if it's $1 or $20. Shipping will dominate anyway.

[FlyingDutch]

Hello,

some time ago I bought more advanced version of "Maix-1": Sipeed Maix-1 RISC-V Dual Core 64bit With FPU AI Module Core Board in banggood.com.
After terst I can say that it is awsome 

I am interested in simpler version 32-bit (one core) of RISC-V ICs. Good luck in your enterprise.

Best Reagards

[ataradov]

more info,  it will be like a clone of stm32, but with RISC-V core, and high-end version will have USBFS.

If it is really a clone of STM32, it will be a great seller.  But we need to clarify what is meant by the "clone". The key here is to have similar electrical design too. If your device will need separate core voltage regulator, or take up a whole bunch of pins for external filters for the PLLs or something like this, then it becomes less interesting.

[lucazader]

I would definitely be interested in a 20c high performance risc-v microcontroller.
I use stm32's all the time at work.

It would be good to have a cheaper options that uses nice open source tools (like gcc or llvm) like the risc-v architecture does.
Is it planned to have internal flash or external flash?
Do you have a planned target performance, eg target MHz, target mips etc?
Do you have a planned target power consumption (uA/MHz) and or a target sleep consumption?

[ehughes]

I would rather see something that is more expensive.    Outside of hobby LED blinkers,     customers are looking for good support, reliability,  documentation, long term availability and good supply in the distribution channel. 

I can't see a $0.20 part being useful outside of throw away toys and hobby projects.        I would rather see a robust device with the RISCV architecture being used in a useful offering of parts.

[ataradov]

You are assuming that $0.20 device will be bad, it does not have to be that way. I assume that the hardware would be at least competitive with high end Cortex-M0+ devices.

Documentation is an open question. But I can live with bad documentation for some time if the chip is new. I'm sure documentation will improve if it becomes clear that the chip is good and worth using.

[wilfred]

You are assuming that $0.20 device will be bad, it does not have to be that way. I assume that the hardware would be at least competitive with high end Cortex-M0+ devices.

Documentation is an open question. But I can live with bad documentation for some time if the chip is new. I'm sure documentation will improve if it becomes clear that the chip is good and worth using.

I'm not sure that was the assumption. It could be if the price was $3.20 it'd be fine and a much more robust option. Even if it was the same device. Apple products are the exception of course. That Apple products exist shows there is a market for products that are needlessly expensive. I'm not trying to bash Apple, my point is that there are those for whom price equates to quality. It might be true for Italian shoes and handbags. Less true for Italian sunglasses and not true for technology especially where the development was funded by taxpayers and the price reflects manufacturing and labor costs.   

[NorthGuy]

... there are those for whom price equates to quality.

I'm sure engineers know better than this.

[wilfred]

... there are those for whom price equates to quality.

I'm sure engineers know better than this.

Read here long enough and you might be less certain. But that's not a debate I want to start.

[Fire Doger]

There are 3 types of buyers:
Hobby
prof short life production
prof long life production

For long life productions it's hard to sell because they want chips to be available in 10-15 years and they don't mind pay a bit more on famous brands to be safe.
short life productions depends on specs, price, documentation and availability. If you can only find it in China it won't be the first choice, for a few cents they will prefer stm etc...
For hobby if someone makes *arduino* plugin it will sell like crazy if at ebay costs 1-1.2€

Personally I choose based most on ease of use to deliver faster to market.
Debug! If I can't debug it properly it's a toy...
Reliable and cheap debug tools or use existing tools (Jlink etc)
Good abstraction layer libs (well documented) and many examples, many!
Open dev boards with many peripherals. I like having a reference for peripherals, transceivers, etc... Plus bread-boarding time costs money at work.
Support

Then there is the classical comparison of specs-price...
I would consider buying a dev board if it had a ton of examples, otherwise I will wait someone else to make the hard work first...

[westfw]

A scalable instruction set is relatively meaningless unless chip vendors implement devices at "many" of the price/performance points.  RISC-V will be a bit disappointing if all the chips that come out for sale are of linux-level complexity and performance, and I am very interested in seeing a low-end microcontroller-class RISC-V chip.  At least from an academic point of view; I'm afraid I can't promise to buy millions of them :-(
However, I'm worried about software support.  In the ARM world, there are plenty of small Cortex-M0 and M0+ chips, but the state of "small" compiler libraries is still pretty poor - libgcc still lacks optimized software floating point (which exists for CM3/CM4), newlib (even in it's "nano" configuration) is significantly larger than the similar libraries available for 8bit CPUs (ie avr-libc), and vendor libraries also seem to assume relatively large program space.  I can see RISC-V falling into the same trap.

There are 3 types of buyers:
Hobby, prof short life production, prof long life production

I'll add a forth: "Educational and academic" - for instance, AFAIK, MIPS is much more popular in university classes on assembly language and computer architecture than it is in the marketplace.   Academic users don't necessarily buy chips (vs simulation), but it would be good to have that option.

[Fire Doger]

There are 3 types of buyers:
Hobby, prof short life production, prof long life production

I'll add a forth: "Educational and academic" - for instance, AFAIK, MIPS is much more popular in university classes on assembly language and computer architecture than it is in the marketplace.   Academic users don't necessarily buy chips (vs simulation), but it would be good to have that option.

Meh, for marketing I agree but you can't make profit as chip manufacturer from educational and academic, most of vendors gives them for free at students to get them familiar with their tools-chips.
They have the same demand with hobby buyers: cheap tools, low quantity, dip package, nice documentation
Microchip had very cheap pickit3 (and clones cost a few $) with debug and gives free IC to everyone with academic domain email...

[neil555]

I'd definitely be interested depending on how much SRAM was included, at least 64K would be good

[tszaboo]

Interesting? Depends on the ecosystem.
If it has USB bootloader, interesting peripherals, easy to start with IDE (think of Arduino) with a way for professionals to continue, than it can be a hit.
Like if you build in battery-power management with USB charging, and and RF interface, like Bluetooth, Zigbee or 802.15.4, you would be selling the chip in the billions.

[PCB.Wiz]

I'd definitely be interested depending on how much SRAM was included, at least 64K would be good

That will not be the banner '20 cent RISC-V MCU' anymore...

Interesting? Depends on the ecosystem.
If it has USB bootloader, interesting peripherals, easy to start with IDE (think of Arduino) with a way for professionals to continue, than it can be a hit.
Like if you build in battery-power management with USB charging, and and RF interface, like Bluetooth, Zigbee or 802.15.4, you would be selling the chip in the billions.

USB was mentioned in a 'more expensive part' and any RF bumps it further up the price curve, well away from the banner '20 cent RISC-V MCU"

[tszaboo]

I'd definitely be interested depending on how much SRAM was included, at least 64K would be good

That will not be the banner '20 cent RISC-V MCU' anymore...

Interesting? Depends on the ecosystem.
If it has USB bootloader, interesting peripherals, easy to start with IDE (think of Arduino) with a way for professionals to continue, than it can be a hit.
Like if you build in battery-power management with USB charging, and and RF interface, like Bluetooth, Zigbee or 802.15.4, you would be selling the chip in the billions.

USB was mentioned in a 'more expensive part' and any RF bumps it further up the price curve, well away from the banner '20 cent RISC-V MCU"

Without new features, it is just "yet another microcontroller" . I mean the CH554 costs 25 cents, and around 1 USD, there are already Cortex M0+ with USB from digikey. I mean, you need to show something new, because if you just have a new core, nobody will care.

[legacy]

RISC-V SoC that can run Linux.
With a decent coherent cache and PCIe!
oh, and a book "see RISC-V run"

[legacy]

There are 3 types of buyers:

Now, there are 4 types of buyers

• Hobby
• prof short life production
• prof long life production
• educational and academic

 

[brucehoult]

There's been quite a lot of dreaming in this thread!

Yes, we'd all love a 1+ GHz multi-core Linux-capable RISC-V SoC for $1. That's just not going to happen in the near future.

The Kendryte 210 is a good example of what's realistic, though I'm amazed they managed to get it as cheap as $8.

The SiFive FE310 (32 bit, 320 MHz, 16 KB SRAM, 16 KB iCache, some GPIOs/PWMs) is retailing through CrowdSupply for $5 each (actually $25 for a 5-pack). You can be sure CrowdSupply are making a tidy markup on those. And those are still being made on MPWs. If the FE310 was put into volume production on dedicated full-reticule masks with a good number of wafers made then it would certainly be well under $1, and possibly approaching $0.20 -- though I think $0.20 is getting close to the cost of merely packaging the die.

That's a kind of ballpark that a 20c SoC would be in from sipeed. You could get different peripherals in there (but not a lot *more* as pins are expensive), or a bit more RAM. 64 KB? Maybe, but to be honest, probably less than 16 KB, to make room for onboard flash.

Someone mentioned CH554 at 25c. Good grief! 14 KB of flash and 1.25 KB RAM. And an 8051 CPU which is awful to program by hand, and absolutely appalling code density if you use a C compiler -- at a guess that 14 KB flash would be as useful as 4 KB (8 KB, tops) on an ARM or RISC-V unless you have an army of code ninjas writing everything by hand.

[zepan0]

It will have 16~64KB SRAM,  64~256KB Flash, and all interface that STM32F1 have.

[ebastler]

Now, there are 4 types of buyers

• Hobby
• prof short life production
• prof long life production
• educational and academic

 

But academic institutions (hopefully) want to teach their engineering students skills which are relevant in real, professional life. And they have an interest in keeping their curriculum low-maintenance, i.e. they do not want to overhaul their lab courses every other year. So their needs should be very similar to those of professionals working on designs with a long production life.

[GromBeestje]

all interface that STM32F1 have.

Do you mean it will be pin-compatible?

[FlyingDutch]

Hello,

in my humble opinion better if the price would be higher, let say 5US $, but have most of the stuff that 64-bit MAix-1 has. I mean FPU, AI booster, DSP blocks and interesting peripherals like counters (also PWM) and comunication interfaces: I2C, SPI, UARTS. The Flash size best 256 KB. I also in my work use mainly ARM-Cortex (from M3 to M7).

Best Regards

[lucazader]

If this

It will have 16~64KB SRAM,  64~256KB Flash, and all interface that STM32F1 have.

I this is the case, then thats great. The F1 series has a lot of useful general purpose peripherals.
I suppose this is quite a good market to go for, as lots of companies currently use the very cheap F103 in a lot of products.
Having the same peripherals and a possibly higher performance core for cheaper will definitely be great.

As others have said having a good debugging experience and code development tools that are useful will also go a long way to seeing wide adoption

[brucehoult]

Something worth mentioning here in case people aren't aware of it is that the price of a chip is strongly dependent on the number of pins coming out.

Obviously a bigger package with more pins and more wires to the die will cost more, but even more than that, the cost of the die itself (which is directly proportional to its area) can be dominated by the area for the pads with the MCU, SRAM, flash a relatively small blob in the middle of the die.

That's not such a big issue with a 32 bit MCU on a 180nm process (or 350 or 500 of course) such as the one below, but if you made that same design in 28nm you'd be pad-dominated and not get anywhere near as much area savings as you might think.

This of course is why so many cheap MCUs have a lot of peripherals but nowhere near enough pins to use them all at the same time, and a pinmux.

[Doctorandus_P]

I'm interested, but it does not have to be 20ct.


I've bought some 10 "Blue Pill" boards and about 20 STM32F103C8T6 chips "just for fun" to play with.
I choose this processor because I was getting a bit bored by the Atmel chips, and I very much like peripherals such as a shitload to timers, native USB, built in motor controller timer, DMA, multiple interrupt levels and other goodies.

I dislike the ESP8266 and ESP32 mainly because a serious lack of documentation. I know the're popular in the hobby market, but a 20 page leaflet called a "datasheet" is so bad I have trouble with understanding that it's become popular at all.

For prices upto EUR 2 it would be a no brainer for me. Put my STM32 chips in a drawer and focus on Risc-V. But it has to have good documentation and tools.

[thm_w]

I dislike the ESP8266 and ESP32 mainly because a serious lack of documentation. I know the're popular in the hobby market, but a 20 page leaflet called a "datasheet" is so bad I have trouble with understanding that it's become popular at all.

ESP32 datasheet (60 pages): https://www.espressif.com/sites/default/files/documentation/esp32_datasheet_en.pdf
ESP32 technical reference (669 pages): https://www.espressif.com/sites/default/files/documentation/esp32_technical_reference_manual_en.pdf

[GromBeestje]

I've mainly experience with ARM-based microcontrollers  (STM32, nRF52, PSoC4). I prefer those chips mainly because they've decent debugging capabilities (JTAG/SWD).

One thing I like about the STM32 chips is that they're pin compatible between different series (eg, you can swap an STM32F1 with an F0, F3, L0, F1) (But the new G0 series use a different pinout, I made that mistake) so you can use the same PCB for any STM32 with the same footprint.

I've only looked at the ESP8266 but not the ESP32. The ESP8266, little I/O, seems there is some binary blob running in the background. I've tried to connect to an ESP8266 using JTAG using some openocd fork I found, without success. I've tried this gdbstub I found. but that doesn't work stable. I don't like the thing.

[SiliconWizard]

@zepan0: do you already have an idea about what process node you would use, max clock frequency and approximate power consumption per MHz?

[iMo]

I would expect a 55nm TSMC process, 250300MHz clock @250uA/MHz @3.3V with all peripherals on