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The “terrible” 3 cent MCU – a short survey of sub $0.10 microcontrollers

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Re: The “terrible” 3 cent MCU – a short survey of sub $0.10 microcontrollers

#31

Post by petra »

ChuckMcM wrote: post #2

It is interesting that its possible to produce chips at this price for more than a short time period. Also that they are all basically PIC clones or variants speaks to the core competency of these companies is manufacturing and operational efficiency, not MCU design. I think a fascinating experiment here would be to invest some time in an unencumbered scalable design that could be implemented very inexpensively (say…

Here's this experiment sort-of running:

WCH, which sells cheap mcu's(like $0.25 8051-mcu with usb/16Kflash) is working on a risc-V bluetooth mcu:

https://www.cnx-software.com/2019/02/16/wch-ch572-risc-v-mcu...

And since risc-v has versions somewhere around 5K-10K gates, well, a lower end mcu isn't far, probably.

Still, it would be interesting to think how we can get from that, to standard peripherals, and standard pinouts, used by at least 2 mcu makers. That would be interesting.

Re: The “terrible” 3 cent MCU – a short survey of sub $0.10 microcontrollers

#32

Post by firethief »

> They address a specific category of low-cost, high volume, non-serviceable products with limited functionality. You need to wait for the push of a button and then let an LED flash exactly five times? You need to control a battery-operated night light? The sub $0.10 MCU is your friend to reduce BOM and shorten development time.

If you're allergic to 555s, I guess?

Re: The “terrible” 3 cent MCU – a short survey of sub $0.10 microcontrollers

#33

Post by throwaway2048 »

firethief wrote: post #32

> They address a specific category of low-cost, high volume, non-serviceable products with limited functionality. You need to wait for the push of a button and then let an LED flash exactly five times? You need to control a battery-operated night light? The sub $0.10 MCU is your friend to reduce BOM and shorten development time. If you're allergic to 555s, I guess?

These are cheaper than 555s, more easily available in various footprints, need almost no supporting passive circuity or glue logic, lower power usage, and more flexible to boot.

Popularity of the 555 waned a long, long time ago.

Re: The “terrible” 3 cent MCU – a short survey of sub $0.10 microcontrollers

#34

Post by nsxwolf »

firethief wrote: post #32

> They address a specific category of low-cost, high volume, non-serviceable products with limited functionality. You need to wait for the push of a button and then let an LED flash exactly five times? You need to control a battery-operated night light? The sub $0.10 MCU is your friend to reduce BOM and shorten development time. If you're allergic to 555s, I guess?

For the push button example I can envision using a pair of 555s or a 556 as a timer for the flashing and a latch to store the success condition, but how does it count to 5? You need more logic in here, so why not a cheap programmable chip?

Re: The “terrible” 3 cent MCU – a short survey of sub $0.10 microcontrollers

#35

Post by HeyLaughingBoy »

firethief wrote: post #32

> They address a specific category of low-cost, high volume, non-serviceable products with limited functionality. You need to wait for the push of a button and then let an LED flash exactly five times? You need to control a battery-operated night light? The sub $0.10 MCU is your friend to reduce BOM and shorten development time. If you're allergic to 555s, I guess?

The logic you'd need to add to a 555 to flash an LED exactly five times would likely cost more than doing it in an MCU.

Re: The “terrible” 3 cent MCU – a short survey of sub $0.10 microcontrollers

#36

Post by nsxwolf »

dbcurtis wrote: post #3

These have their uses. A friend who frequently does contract development in the toy space has (or at least used to have) a favorite go-to MCU that costs under $0.06 in bare die. It is essentially a 6502 with 100 bytes of RAM and a metric butt-load of mask-programmable ROM. It was originally designed for greeting cards. He has designed it into toys. It is hard to use, you need a dev kit and a good relationship with th…

Is a "expoxy encapsulation depositer" the thing that makes those black blobs?

Re: The “terrible” 3 cent MCU – a short survey of sub $0.10 microcontrollers

#37

Post by zokier »

childintime wrote: post #29
the-dude wrote: post #5

Around the year 2000, a PIC 12C508A was about 1 Dutch guilder @ 5000 pcs. Today, Mouser lists 1 pcs @ € 0,908, 100 pcs @ € 0,863. The guilder/€ is 2,20371 ( muscle memory ). The MCUs in the article are 12C508A class, one is an actual clone. So for ~ € 0,80 at quantity, the 12C508A currently costs about 1.75 guilder. 20 years later.

I wonder how much of Microchip revenue is from old chips at very profitable prices. I did a Digikey comparison once, and Microchip alone provided roughly 30% of all MCUs on digikey. It has, for example, an incredible 175 MCU models with exactly 64B of RAM, 1.75KB of ROM and just 5 I/Os.

That is just combinatorial explosion of fairly small number of features. I took a peek at the example you provided, and drilling down there seems to be for example 39 SKUs for PIC12x615 chip:

* Two voltage options (although why on earth do they need 2-5.5 and 2-5 separately?)

* Two main packaging options: tape and tube, and tape is furthermore available as full reel, digireel, and cut tape

* Three different temperature ratings

* Five different device packages from tiny 3x3mm DFN to full-sized DIP

So already from these fairly simple options you get total of 2x4x3x5 = 120 different combinations for essentially the same chip. So they don't quite have all the combinations, but there are few outlier options and overall the combination coverage is pretty wide which explains the inflated SKU count. I'm not sure what conclusions can be drawn from this exercise besides that Microchip seem to be willing to provide their chips exactly as customer wants them.

Re: The “terrible” 3 cent MCU – a short survey of sub $0.10 microcontrollers

#38

Post by vardump »

benj111 wrote: post #20
dbcurtis wrote: post #3

These have their uses. A friend who frequently does contract development in the toy space has (or at least used to have) a favorite go-to MCU that costs under $0.06 in bare die. It is essentially a 6502 with 100 bytes of RAM and a metric butt-load of mask-programmable ROM. It was originally designed for greeting cards. He has designed it into toys. It is hard to use, you need a dev kit and a good relationship with th…

"metric butt-load of mask-programmable ROM" What would that be in this context? I'm guessing we're talking KB rather than TB?

I'd guess about 1 MB order of magnitude. That would be a butt-load even for samples.

1 MB would be enough for 45 seconds audio at 8 bit PCM @22 kHz. If they're half competent, they could use ADPCM or much better (and cheaper to decode too!) vector quantization.

With VQ, you could go even down to ~1 bits (~6 minutes of audio per megabyte) per sample while maintaining good audio quality. Decoding is very simple, so 6502 would have plenty of oomph to do that.

Re: The “terrible” 3 cent MCU – a short survey of sub $0.10 microcontrollers

#39

Post by andrehacker »

dbcurtis wrote: post #3

These have their uses. A friend who frequently does contract development in the toy space has (or at least used to have) a favorite go-to MCU that costs under $0.06 in bare die. It is essentially a 6502 with 100 bytes of RAM and a metric butt-load of mask-programmable ROM. It was originally designed for greeting cards. He has designed it into toys. It is hard to use, you need a dev kit and a good relationship with th…

Ah, yes, there was an article here a year back about the original Furby using that same configuration. The article actually had the annotated 6502 source code.

https://news.ycombinator.com/item?id=17751599

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