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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

#21

Post by joezydeco »

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…

I would think a lot of manufacturers are looking to RISC-V for that kind of eventuality. But in the meantime, and looking at that chart, it seems a lot more convenient to just rip off the PIC.

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

#23

Post by jacobrobbins »

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?

the poster mentioned it was for greeting cards, I remember their used to be a lot of greeting cards that would play a recording when you opened them. I bet they loaded low-quality samples into the ROM for that.

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

#24

Post by Taniwha »

joezydeco wrote: post #21
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…

I would think a lot of manufacturers are looking to RISC-V for that kind of eventuality. But in the meantime, and looking at that chart, it seems a lot more convenient to just rip off the PIC.

I don't think they are "ripping off the PIC", I think they are reimplimenting the PIC ISA, just like 8051s are reimplemented all over the place

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

#25

Post by pkaye »

ska wrote: post #13
mastax wrote: post #7

Some Philips sonicare toothbrushes use(d) a 4-bit microcontroller from an obscure Swiss company. (From memory, since I can't find the EEVBlog video teardown) 52 bytes of RAM, custom size mask ROM, ? Kilohertz clock speed. It makes sense, they just needed a timer for the "2 minutes of brushing is up" feature, and maybe some battery management. It still surprised me that it was worth the hassle to save a few cents, eve…

It's pretty easy to make the hassle worthwhile, if you are selling (particularly many) millions of things. Even saving a dime on BOM for a million units shipped will pay an engineer year, roughly. I still remember a friend relating with a mixture of horror and fondness that in 15 years probably the biggest impact he ever had to the bottom line of [big computer manufacturer no longer in existence] was re-routing a PCB…

A product I was working on had different variants based on what parts are populated. There were config resistors to help route the signals based on what was populated. I replaced that all with a simple software lookup table in firmware to reroute the signals correctly. Furthermore I figured out how to auto-detect the dozens of supported configurations on first bootup. The PCBs were very small so I made the board designers job a lot easier due to eliminated resistors. The factory folks were thrilled that they didn't have to manage the jumpers.

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

#26

Post by pkaye »

ChuckMcM wrote: post #8
dbcurtis wrote: post #6

Earlier quoted context omitted.

> I think a fascinating experiment here would be to invest some time in an unencumbered scalable design that could be implemented very inexpensively (say less than 10K gates). Would these manufacturers pick up that design and run with it, I have done that thought experiment many times. I have a ISA that I sketched out many years ago but never did anything with. Often, I have thought it would be a real hoot to put up…

I think you should still post it to github :-). Agreed on the peripherals as well, I good set of open source peripheral models in verilog would be a useful addition to the mix.

Have you heard of opencores.org? Its been around for a long time.

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

#27

Post by monocasa »

joezydeco wrote: post #21
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…

I would think a lot of manufacturers are looking to RISC-V for that kind of eventuality. But in the meantime, and looking at that chart, it seems a lot more convenient to just rip off the PIC.

I don't think a RISC-V would fit in this gate count niche. Just the register file for an RV32-C core is half these chips' RAM.

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

#28

Post by jerryr »

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…

That sounds very similar to my experience with toy development. For a toy that played a bunch of pre-recorded sounds, we used a 4-bit Winbond MCU (their MCU division is now Nuvoton) that had a tiny bit of RAM and a ton of mask ROM. Firmware development was done in assembly and targeted a huge (physically large) emulator for test/debug. When we were satisfied with the firmware, we'd send it off to our CM, who would then order the parts with our FW in ROM. They'd get back bare die parts, which were wire bonded to the PCB and then epoxied over (that miserable "glop top" packaging, which is the bane of many teardowns). Development was a bit painful, but high volume production was extremely cheap.

Edit: Oops. I conflated projects. The toy project actually used a SunPlus MCU, not a Winbond MCU. It was an 8-bit RISC CPU running at 5MHz with 128 bytes RAM and 256KB mask ROM. The ROM held both the program and audio samples. I don't recall what encoding was used for the audio.

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

#29

Post by childintime »

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.

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

#30

Post by somesortofsystm »

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…

>6502

Without question, one of the nicest platforms to have in multitudes of thousands, at low energy and cost ..

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