EEVblog #1132 - The 3 Cent Microcontroller!

[EEVblog]

Taking a look at a sub 3 cent microcontroller, and other obscure Chinese manufactures, how to find them, and were to get them in stock.

http://www.padauk.com.tw
https://lcsc.com

[MT]

If it can replace a 555 its all chicken dinner! 

All kind of oddbal manufacturers there, i actually is looking for SPDT analog switch sot23-6 5V from the regular channels, Farnell dosent even sell such a thing but found one on Taiwan LCSC.
https://lcsc.com/product-detail/Analog-Switches_BL1551_C82528.html

[ucanel]

I agree you need to do a project with it,
i would like to help.

[woox2k]

Yes show us how easy or frustrating it is to build a project with it!

[Nusa]

Do they cost more to ship than they do to buy?

[nathanpc]

Watching Dave try to build a simple project with one of these MCUs is going to be priceless. I've always wanted to give them a try just for fun. Has anyone here ever tried one of these?

That IDE looked a bit outdated, but it has a lot of functions that would be nice, specially for ARM development where you have to set a billion registers to setup peripherals the way you want. By the looks of it these MCUs are almost always used for simple tasks and the developers just use the generated code and modify it slightly to fit the application.

[drussell]

Do they cost more to ship than they do to buy?

Under most circumstances, yes. 

[xl0]

Sorry to burst the bubble, but that's not the real price. How do we know?

- The price is much lower than for comparable Chinese / Taiwanese micros.
- Nobody else in Shenzhen is selling them. Yes, you can not buy this thing in Shenzhen, only lcsc has 500 in stock, and that's nothing.

It looks like lcsc (The large go to distributor in Shenzhen) gave Paduk (a very small and relatively new Taiwanese mcu designer) a try and bought a bunch of their parts in 1K quantity. Now they are selling them off just to clear the inventory.

If you want cheap micros that are going to be available for the same price in the foreseeable future, try Holtek and STC. Holtek is Taiwanese and they have very decent English documentation and tools. STC is Chinese and used to have a Chinese-only website that would give regular visitors eye cancer. I see they updated the website and now have an English version. They are even translating the datasheets, but expect a rougher experience.


In any case, the cheapest Holtek HT48R002 OTP micro is just 9 cents on lcsc, and you can get it for 6 in reasonable quantity in Shenzhen. Yes, it's still very cheap, but not 3 cents in quantity of 10 cheap.

[SiliconFrog]

Id really like to see him have a go at the cheap microcontrollers as well. I have also heard that the Holtek ones are the best to try as they have been around for a while, noted for being the cheap ones and where some brave folk have had a go. I think the data sheets used to all be in kanji but have better english transcription now.

It would be interesting to see it programmed in pure assembly instead of the odd asm/C hybrid. And also good to know if they can be programmed using some bit bashing from the IO of something else like a PIC / Arduino / Raspberry or similar instead of using a special custom programmer.

Also:

Do they cost more to ship than they do to buy?

Probably but recall that lcsc is part of the jlcpcb group so if you get some PCBs made and pay for their shipping then you can get components from this supplier tacked on to the same shipping consignment. I have done this and got "free" shipping of the components for an old jlcpcb board.

See: https://support.lcsc.com/article/24-do-you-offer-combine-shipment-with-pcbs

[Bud]

The IDE probably does not have that compile menu rubbish, instead it may write directly to the programmer.

[NiHaoMike]

Sorry to burst the bubble, but that's not the real price. How do we know?

- The price is much lower than for comparable Chinese / Taiwanese micros.
- Nobody else in Shenzhen is selling them. Yes, you can not buy this thing in Shenzhen, only lcsc has 500 in stock, and that's nothing.

It looks like lcsc (The large go to distributor in Shenzhen) gave Paduk (a very small and relatively new Taiwanese mcu designer) a try and bought a bunch of their parts in 1K quantity. Now they are selling them off just to clear the inventory.

How likely would that company still be in business in the near future? Maybe the chips would become super valuable in 30 years or so.

[GigaJoe]

Dave, really ...

[VEGETA]

They have other stuff that are super cheap (at quantity of 1):

DAC:

dual-channel 24-bit DAC (0.25$): https://lcsc.com/product-detail/Analog-To-Digital-Converters-ADCs_HX710C_C124156.html
dual-channel 24-bit DAC (0.32$): https://lcsc.com/product-detail/Analog-To-Digital-Converters-ADCs_HX712_C118237.html
dual-channel 16-bit DAC (0.12$): https://lcsc.com/product-detail/Digital-To-Analog-Converters-DACs_TM8211_C92003.html
dual-channel 16-bit DAC (0.12$): https://lcsc.com/product-detail/Digital-To-Analog-Converters-DACs_PT8211-S_C92004.html


ADC:

dual-channel 24-bit ADC (0.25$): https://lcsc.com/product-detail/Analog-To-Digital-Converters-ADCs_HX710C_C124156.html
dual-channel 24-bit ADC (0.33$): https://lcsc.com/product-detail/Analog-To-Digital-Converters-ADCs_HX720_C126715.html
dual-channel 24-bit ADC (0.52$): https://lcsc.com/product-detail/Analog-To-Digital-Converters-ADCs_HX710A_C68417.html
dual-channel 16-bit DAC (0.79$): https://lcsc.com/product-detail/Analog-To-Digital-Converters-ADCs_TM7705_C84305.html

While these prices are literally order of magnitudes of impossible at digikey... here is the question: are these reliable and for real?

I mean, are 24-bit ADCs listed above really does what it claims?! then why will we buy significantly more expensive ones?

[xl0]

Yeah, HX710 and others are legit. But they are digital scale ADCs, not general purpose ones.

[Psi]

Can you load code into ram over debug then run it, or do you have to brick one IC every time to try your code?

[oPossum]

I suspect it is strict Harvard architecture, so no execution from RAM.

[Nusa]

There's only 64 bytes of ram on the thing anyway. You pretty much have to put the program in the 1K words of rom.

[VEGETA]

Yeah, HX710 and others are legit. But they are digital scale ADCs, not general purpose ones.

Meaning I cannot use them for in a lab power supply design? why?

[EEVblog]

It looks like lcsc (The large go to distributor in Shenzhen) gave Paduk (a very small and relatively new Taiwanese mcu designer) a try and bought a bunch of their parts in 1K quantity. Now they are selling them off just to clear the inventory.

Do you have any evidence of that? Or are you just speculating?

As for new, 2005, so been around 13 yeras.
http://www.padauk.com.tw/en/about/index.aspx?kind=9

[coppice]

Yeah, HX710 and others are legit. But they are digital scale ADCs, not general purpose ones.

Meaning I cannot use them for in a lab power supply design? why?

The problem with these devices for many uses is their DC offset. The DC offset in most sigma delta ADCs is not great, and may drift around with temperature and power conditions. In weight scale applications you can measure and subtract the offset each time you start the scale, and assume the temperature, and other factors which can cause the DC offset to drift, won't change too much before the scale is reset again. If you do not have a practical scheme like that for calibrating away the offset, the ADC might not be for you.

[xl0]

Do you have any evidence of that? Or are you just speculating?

Just speculating.

As for new, 2005, so been around 13 yeras.

You are right, not that new.

[VEGETA]

Yeah, HX710 and others are legit. But they are digital scale ADCs, not general purpose ones.

Meaning I cannot use them for in a lab power supply design? why?

The problem with these devices for many uses is their DC offset. The DC offset in most sigma delta ADCs is not great, and may drift around with temperature and power conditions. In weight scale applications you can measure and subtract the offset each time you start the scale, and assume the temperature, and other factors which can cause the DC offset to drift, won't change too much before the scale is reset again. If you do not have a practical scheme like that for calibrating away the offset, the ADC might not be for you.

Aha, what about the other ADCs\DACs listed aside from those? I mean the 16 bit ones as they seem so cheap and there is nothing in their datasheet to indicate for weight scale application specific.

[Kjelt]

We will see if the stock is restocked we will know the answer.
In the past I had a similar experience with a chinese seller who sold STM32 microcontrollers for $0,80.
I ordered 100 pieces and he sent and billed me 34 pieces.
I asked him when the other 66 pieces would be shipped and he answered never, out of stock.
At my further inquiries he admitted purchasing a leftover reel in the past with couple of hundred pieces left and just offers what he has.
 
LCSC looks like a big company so I am really interested to see how this turns out.

[janekm]

- Nobody else in Shenzhen is selling them. Yes, you can not buy this thing in Shenzhen, only lcsc has 500 in stock, and that's nothing.

Actually there are at least two other distributors in SZ and Padauk have an official distributor with full app engineer support in SZ (who can also do pre-"flashed" chips).

I do suspect the price could go up if the part gets very popular... ST pulled that trick with STM8 before.

[janekm]

BTW there "multi core" chips are also very interesting... they are why I got talking to Padauk in the first place. What they are is essentially a single core but it can task-switch between multiple tasks on every execution cycle (so it must have multiple register and PC sets). Which can be very useful for protocol conversion as you could bitbang multiple protocols at once. Their other advertised use case is for motor controllers (and it looks like they have a pre-programmed chip for that application).