Everything You Want To Know About The Cheapest Processors Available

Those of us who use microprocessors in our work will be familiar with their cost, whether we are buying one or two for a project or ten million on reels for a production run. We’re used to paying tens of cents or maybe even a dollar for a little microcontroller in single quantities, and these are probably the cheapest that we might expect to find.

There is a stratum of cheaper devices though, usually from Chinese manufacturers with scant data in English and difficult to source in Europe or the Americas. These chips cost under ten cents each, a figure which seems barely credible. To shed some light upon this world, [cpldcpu] has produced a run-down of some of the available families that even if you will never work with such an inexpensive option still makes for a fascinating read.

These processors are not the type of component you would use for high intensity tasks so it’s probable that you will not be mining cryptocurrency on a brace of them. Thus their architecture is hardly cutting-edge, with the venerable PIC12 being their inspiration and in some cases their direct copy. These are all write-once devices and some of their toolchains are variable in accessibility, but perhaps they aren’t as terrible as some would have you believe. If you are looking for inspiration, we’ve featured one of them before.

TL;DR: the Padauk PFS173, at just under $0.09, has an open-source toolchain and a decent set of peripherals.

Thanks [WilkoL] for the tip.

Image: A real PIC12 die shot. ZeptoBars [CC BY 3.0]

45 thoughts on “Everything You Want To Know About The Cheapest Processors Available

      1. yeah, I was wondering though, if any of the OTP ones have a Flash equivalent?
        That way, one could develop the code (repeatedly, sigh) on the Flash version, and then when the software/firmware finally works, just load it onto an OTP.
        I suspect if a Flash one doesn’t have the same registers, RAM, ROM, etc, compiled code might try to access something that is not available during execution.
        I’m not talking (err… writing) about an emulator, but actual hardware.

        1. Sure, but when a transistor costs $0.02, caps start around a nickel, and a resistor is the better part of a penny (source: digi-key, through-hole parts, qty 100), it starts looking silly to *not* use a micro!

          1. Depends on caps you use. Cheapest ones I could find at my local major distributor sell for less than 0,001781374USD per unit. Cheapest transistor (MMBT3904-LIT) sells for less than 0,00763446USD…

          2. Sure, but how many hobbyists are going to buy enough for those prices? How much are they in a more likely quantity for experimentation, such as 100?

            The MMBT3904 is $0.0396 at digikey when buying 1000 (1/3 of a reel). I’m sure other vendors are cheaper, but they’re probably also cheaper on the through-hole components I looked up.

          3. The programming would cost extra during the manufacturing process as it adds extra steps in the testing. So are keeping track of inventory vs firmware versions etc. There also is the NRE for the software, test jig needed for programming etc. You have to add up all the hidden cost to get the full picture.

            Sometime it can still ended up cheaper.

          4. the truth of the matter is that I’m a better programmer any day than I am a circuit designer. I can build a nice project for about $3 worth of parts from china that I’d never be able to design with electronic components and I dont have a problem with that at all.

  1. Using these in my personal projects would not be fun as the architecture is too old, slow and I bet you the documentation/tools is/are incomplete. I would never use these in any professional project either. So I fail to see the use case for this product. Price is not everything.

    The STM32G070 is around $1.60 in unit quantities and under $0.80 in 1000+ quantities. Comes with a decent low power core (64MHz Cortex-M0+) and peripherals, plenty of flash (128KB) and RAM (36 KB RAM) and excellent tools and docs. To me that’s a much better deal to be honest.

    1. You completely missed the point. The article examines these ultra low cost chips and nothing more. It’s not saying *you* should base your designs around them. Given that companies are cranking them out by the millions it looks like their market is doing well.

        1. I think they got those boiled down to an ASIC consisting of a ripple counter and an analog flash ROM no DACs or anything needed.
          They used to sell such a recording chip at radio shack in a DIP package.

    2. “1000+” quantity is nothing in the real world consumer and industrial applications. You’d rarely see an order smaller than 8 digits for “low-IQ” MCUs used for white goods, for example. Dropping price a single cent means 100s of thousands of dolars saved in BOM, which could easily be used to fund another head for the project.

    3. Price *is* everything to the target market of these chips. These aren’t really very useful to a hobbyist nor probably most professionals in the West, but if you want to make a cheap disposable blinky gadget, these are gonna be your jam.

      Supposedly the Padauk docs and toolchain are actually pretty OK, but I haven’t used them myself.

    4. It’s funny to think there are likely dozens of these chips in the computer and accessories you just used to post how you don’t use these chips.
      But I understand, personally, I never use the Internet.

  2. Not a surprise there isn’t decent English, or any other languge than “Chinese”, documentationtation. My guess the only export export expectation for the CPU’s is in embedded in other products that are ecported. I suppose some enteprise could purchase t CPUs, create decent documentation for esport to other nations, but I doubt that will happen. The US and other former powerhouse manufacturing nation, exporte the means of maufacturing, when they export labor to oppresive wage s nations.. The hobbyist marker is mear speck in the univers. Not to mention any value adde, and the ROI expectation, will increase the cost ot CPUs. An interesting tech report, but I don’t believe it will impact hobbyists. Impact on manufacturers outside of China most likely will be negative.

    1. The Chinese resellers are more than happy to sell to the hobbyists (e.g. aliexpress or lscs) and not hung up on volume. Half the time, some sells on aliexpress have no idea what they are selling so do not expect any level of support.

      It is getting to the point where reading Chinese is becoming more useful. Thankfully the translators are getting pretty good at that and you could point the camera to the screen to translate.

    1. Each fab have different sets of rules and low level library as such you cannot “direct copy” chips the way you think.

      Most of these “clone” chips are functional equivalent of the chips usually implemented taking advantage of a much newer node for smaller die size/lower cost. It is not as simple until you examine the dies and compare the chip layout.

      One is allowed to reverse engineer hardware to provide compatibility. The physical chip layout is protected by copyright, as are the datasheet/manual/software and patents.

    1. But how many components does it take to do anything beyond the trivial case? Say: blink twice, pause, then repeat? Pseudo-random strobe? Or even if you change your mind about the period or on/off time. The added functionality of a micro can be very handy, even with write-once chips, to make a new version of a thing with slightly different behavior, while avoiding a board respin or wasting component inventory.

  3. The big problem is to find who sell them. They might cost 0.10$ at manufacturer, but buying from a distributor you end up at 1.5$ plus shipping (the place where they rip you off with “shipping cost”)

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