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4 Bit MCUs, Still Alive and Kicking?

Started by Rick C June 12, 2022
I'm not sure which group it was in, but someone who designs toys talked about the extremes they would go to for cost reduction, removing useful, but not essential resistors because they were $0.001 each.  

I'm trying to find out if there are still 4 bit MCUs used in new products.  I see a number of companies who make them, but I have no pricing.  I have found 8 bit MCUs that are available for $0.05 each in just moderate quantities at LCSC.  But then, maybe LCSC is not a vendor anyone should depend on.  

Anyone here design with 4 bit MCUs?  Anyone design things that are built in millions?  Is there a difference in price that adds up at such high volumes? 

How about power levels?  8 bit MCUs are pretty low power these days.  Do 4 bit MCUs make a difference in your designs? 

-- 

Rick C.

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On 13/06/2022 03:44, Rick C wrote:
> I'm not sure which group it was in, but someone who designs toys > talked about the extremes they would go to for cost reduction, > removing useful, but not essential resistors because they were $0.001 > each. >
I remember that poster (though not his name) - I believe you are in the correct group. I have no idea if he is still lurking here.
> I'm trying to find out if there are still 4 bit MCUs used in new > products. I see a number of companies who make them, but I have no > pricing. I have found 8 bit MCUs that are available for $0.05 each > in just moderate quantities at LCSC. But then, maybe LCSC is not a > vendor anyone should depend on. > > Anyone here design with 4 bit MCUs? Anyone design things that are > built in millions? Is there a difference in price that adds up at > such high volumes? > > How about power levels? 8 bit MCUs are pretty low power these days. > Do 4 bit MCUs make a difference in your designs? >
As far as I know, there are no longer any 4-bit microcontrollers available for "normal" customers. The last family was the MARC4, from Atmel. There are still some manufacturers that make 4-bit microcontrollers, but they are typically bare-die devices with vast minimum order quantities and masked ROM programs - there are few situations where they are economically viable now. If your company directory does not play golf with the manufacturer's company director, it's unlikely that you'll ever use these devices. The cheapest microcontroller family I know of are from Padauk - they get down to about $0.03 even in quite small quantities, with free toolchains and available datasheets, appnotes, etc.. (Note that the references I have seen are pre-Covid and before the current component availability crisis, so things may have changed.) <https://jaycarlson.net/2019/09/06/whats-up-with-these-3-cent-microcontrollers/> <https://cpldcpu.wordpress.com/2019/08/12/the-terrible-3-cent-mcu/> If you don't need to be quite so obsessive about the price, for $0.50 you should even be able to get 32-bit devices. The choice of peripherals and configuration is probably more important than the core - if you can pick a device with the right pin drives, internal pull-ups or pull-downs, that will save the cost of the device. The cheapest device I have used personally was an 8-bit AVR Tiny - 2 KB flash, no ram, 8 bytes eeprom (IIRC). I don't remember the price, but I believe it was cheaper than the LED on the board. If the tiny coin cell battery on the board had no self-discharge, the system would have had a standby lifetime of about 200 years - pretty low power!
On 13/6/22 17:52, David Brown wrote:
> On 13/06/2022 03:44, Rick C wrote: >> I'm not sure which group it was in, but someone who designs toys >> talked about the extremes they would go to for cost reduction, >> removing useful, but not essential resistors because they were $0.001 >> each. >> > > I remember that poster (though not his name) - I believe you are in the > correct group.&nbsp; I have no idea if he is still lurking here.
Me too. I think the company was Mattel. You might get search hits if you include that. I doubt there is any reason to use such devices these days, even in markets like that. CH
>> I'm trying to find out if there are still 4 bit MCUs used in new >> products.&nbsp; I see a number of companies who make them, but I have no >> pricing.&nbsp; I have found 8 bit MCUs that are available for $0.05 each >> in just moderate quantities at LCSC.&nbsp; But then, maybe LCSC is not a >> vendor anyone should depend on. >> >> Anyone here design with 4 bit MCUs?&nbsp; Anyone design things that are >> built in millions?&nbsp; Is there a difference in price that adds up at >> such high volumes? >> >> How about power levels?&nbsp; 8 bit MCUs are pretty low power these days. >> Do 4 bit MCUs make a difference in your designs? >> > > As far as I know, there are no longer any 4-bit microcontrollers > available for "normal" customers.&nbsp; The last family was the MARC4, from > Atmel.&nbsp; There are still some manufacturers that make 4-bit > microcontrollers, but they are typically bare-die devices with vast > minimum order quantities and masked ROM programs - there are few > situations where they are economically viable now.&nbsp; If your company > directory does not play golf with the manufacturer's company director, > it's unlikely that you'll ever use these devices. > > The cheapest microcontroller family I know of are from Padauk - they get > down to about $0.03 even in quite small quantities, with free toolchains > and available datasheets, appnotes, etc..&nbsp; (Note that the references I > have seen are pre-Covid and before the current component availability > crisis, so things may have changed.) > > <https://jaycarlson.net/2019/09/06/whats-up-with-these-3-cent-microcontrollers/> > > <https://cpldcpu.wordpress.com/2019/08/12/the-terrible-3-cent-mcu/> > > If you don't need to be quite so obsessive about the price, for $0.50 > you should even be able to get 32-bit devices.&nbsp; The choice of > peripherals and configuration is probably more important than the core - > if you can pick a device with the right pin drives, internal pull-ups or > pull-downs, that will save the cost of the device. > > The cheapest device I have used personally was an 8-bit AVR Tiny - 2 KB > flash, no ram, 8 bytes eeprom (IIRC).&nbsp; I don't remember the price, but I > believe it was cheaper than the LED on the board.&nbsp; If the tiny coin cell > battery on the board had no self-discharge, the system would have had a > standby lifetime of about 200 years - pretty low power! > >
On 2022-06-13 Rick C wrote in comp.arch.embedded:
> I'm not sure which group it was in, but someone who designs toys talked about the extremes they would go to for cost reduction, removing useful, but not essential resistors because they were $0.001 each. > > I'm trying to find out if there are still 4 bit MCUs used in new products. I see a number of companies who make them, but I have no pricing. I have found 8 bit MCUs that are available for $0.05 each in just moderate quantities at LCSC. But then, maybe LCSC is not a vendor anyone should depend on. > > Anyone here design with 4 bit MCUs? Anyone design things that are built in millions? Is there a difference in price that adds up at such high volumes? > > How about power levels? 8 bit MCUs are pretty low power these days. Do 4 bit MCUs make a difference in your designs? >
EM Microelectronic still makes them, but custom and mask rom stuff only https://www.emmicroelectronic.com/product/microcontroller-tools-support/ems6500 Not sure this is actually low-cost. They claim ultra low power. For instance this one: https://www.emmicroelectronic.com/index.php/product/multi-io/em6607 -- Stef Never make anything simple and efficient when a way can be found to make it complex and wonderful.
Am 13.06.22 um 09:52 schrieb David Brown:

> > The cheapest microcontroller family I know of are from Padauk - they get > down to about $0.03 even in quite small quantities, with free toolchains > and available datasheets, appnotes, etc..&nbsp; (Note that the references I > have seen are pre-Covid and before the current component availability > crisis, so things may have changed.) >
Before Corona, their cheapest, the PMS15A, was below 1 cent even in small quantitites. That was a device with PROM, though. AFAIR, devices with Flash started at 5 cent when bought in small quantitites. From their financial reports one could see that the average (i.e. across their whole range and all sales) price of their &micro;C was also below 1 cent. There is the free toolchain based on easypdkprog and SDCC, a full free C compiler. And there is the vendor supplied non-free but gratis MINI-C, which, despite the name, is just an IDE with an assembler with a little bit of C syntax sprinkled on top.
> > If you don't need to be quite so obsessive about the price, for $0.50 > you should even be able to get 32-bit devices.&nbsp; The choice of > peripherals and configuration is probably more important than the core - > if you can pick a device with the right pin drives, internal pull-ups or > pull-downs, that will save the cost of the device.
The Padauk approach is that you don't really need most peripherals. Just emulate them in software. If you need accurate timing, put the emulation on its own "core". Padauk has &micro;C with hardware multithreading (implemented as a barrel processor). However, there are severe limitations that make it hard or unfeasible to have more than one "core" running C code (and I never implemented support for that in the free toolchain): https://arxiv.org/abs/2010.04633
Am 13.06.22 um 03:44 schrieb Rick C:

> I'm trying to find out if there are still 4 bit MCUs used in new products.
A few weeks ago, I bought some cyclocomputers. I was surprised to find that even current products are typically based on 4-bit &micro;C. AFAIR, every commercial caclocomputer, on which I found the information had a 4-bit &micro;C.
On Monday, June 13, 2022 at 8:47:32 AM UTC-4, Stef wrote:
> On 2022-06-13 Rick C wrote in comp.arch.embedded: > > I'm not sure which group it was in, but someone who designs toys talked about the extremes they would go to for cost reduction, removing useful, but not essential resistors because they were $0.001 each. > > > > I'm trying to find out if there are still 4 bit MCUs used in new products. I see a number of companies who make them, but I have no pricing. I have found 8 bit MCUs that are available for $0.05 each in just moderate quantities at LCSC. But then, maybe LCSC is not a vendor anyone should depend on. > > > > Anyone here design with 4 bit MCUs? Anyone design things that are built in millions? Is there a difference in price that adds up at such high volumes? > > > > How about power levels? 8 bit MCUs are pretty low power these days. Do 4 bit MCUs make a difference in your designs? > > > EM Microelectronic still makes them, but custom and mask rom stuff only > https://www.emmicroelectronic.com/product/microcontroller-tools-support/ems6500 > > Not sure this is actually low-cost. They claim ultra low power. For > instance this one: > https://www.emmicroelectronic.com/index.php/product/multi-io/em6607
Some have pointed out that 8 bit MCUs are pretty durn low power. I guess the question is if there is enough distinction between 4 and 8 bit MCUs to justify the issues of working with the 4 bit parts. At $0.01 per device, even a million units are only $10,000. That's not a lot of engineering time. -- Rick C. + Get 1,000 miles of free Supercharging + Tesla referral code - https://ts.la/richard11209
On Tuesday, June 14, 2022 at 1:51:28 AM UTC-4, Philipp Klaus Krause wrote:
> Am 13.06.22 um 03:44 schrieb Rick C: > > I'm trying to find out if there are still 4 bit MCUs used in new products. > A few weeks ago, I bought some cyclocomputers. I was surprised to find > that even current products are typically based on 4-bit &micro;C. AFAIR, every > commercial caclocomputer, on which I found the information had a 4-bit &micro;C.
I wonder if this is an example of having the basic design working and sticking with the same device so they don't have to port it? Still, if they are introducing new products using the old MCU design, that's still a new product. -- Rick C. -- Get 1,000 miles of free Supercharging -- Tesla referral code - https://ts.la/richard11209
Rick C <gnuarm.deletethisbit@gmail.com> wrote:
> I'm not sure which group it was in, but someone who designs toys talked about the extremes they would go to for cost reduction, removing useful, but not essential resistors because they were $0.001 each. > > I'm trying to find out if there are still 4 bit MCUs used in new products. I see a number of companies who make them, but I have no pricing. I have found 8 bit MCUs that are available for $0.05 each in just moderate quantities at LCSC. But then, maybe LCSC is not a vendor anyone should depend on. > > Anyone here design with 4 bit MCUs? Anyone design things that are built > in millions? Is there a difference in price that adds up at such high > volumes?
I wonder what process node these MCUs are fabbed on. My understanding is that a design has a certain number of mm2 as overhead for the pads and I/O buffers, and that doesn't scale much with process. If your bond wires or solder bumps are all 100um square and you need X of them, that's a fairly high fixed cost. Meanwhile the cost of laying down a processor is fairly negligible in comparison, so you might as well go for at least 8 bits. About 15 years ago I worked on a project which was building processors on TFT display technology - the same used for the drive electronics for LCD panels. There the feature size was O(10um), which is the same as the Intel 4004, and you could physically see the transistors if you held the panel up to the light. That's the kind of environment where every transistor counts. Another example is organic electronics, eg inkjet printed transistors. But apart from those niches, I can't see what a 4 bit CPU buys you over an 8 bit CPU, given you aren't at such huge process nodes. Theo
On 2022-06-14 Rick C wrote in comp.arch.embedded:
> On Monday, June 13, 2022 at 8:47:32 AM UTC-4, Stef wrote: >> On 2022-06-13 Rick C wrote in comp.arch.embedded: >> > I'm not sure which group it was in, but someone who designs toys talked about the extremes they would go to for cost reduction, removing useful, but not essential resistors because they were $0.001 each. >> > >> > I'm trying to find out if there are still 4 bit MCUs used in new products. I see a number of companies who make them, but I have no pricing. I have found 8 bit MCUs that are available for $0.05 each in just moderate quantities at LCSC. But then, maybe LCSC is not a vendor anyone should depend on. >> > >> > Anyone here design with 4 bit MCUs? Anyone design things that are built in millions? Is there a difference in price that adds up at such high volumes? >> > >> > How about power levels? 8 bit MCUs are pretty low power these days. Do 4 bit MCUs make a difference in your designs? >> > >> EM Microelectronic still makes them, but custom and mask rom stuff only >> https://www.emmicroelectronic.com/product/microcontroller-tools-support/ems6500 >> >> Not sure this is actually low-cost. They claim ultra low power. For >> instance this one: >> https://www.emmicroelectronic.com/index.php/product/multi-io/em6607 > > Some have pointed out that 8 bit MCUs are pretty durn low power. I guess the question is if there is enough distinction between 4 and 8 bit MCUs to justify the issues of working with the 4 bit parts. At $0.01 per device, even a million units are only $10,000. That's not a lot of engineering time.
The fact that EM (and others) still offer 4-bit and have tools available for them suggests to me that there still is a market for them. I know we did have a look at (then) EM Microelectronic-Marin 4-bit processors in the past, but our volumes (and needs) where nowhere near what was feasable for them, so we stuck to 8051. But that was well over 20 years ago. Oops, just spotted the databook on my bookshelf, it's from 1996. ;-) Nowadays we use 32-bit (arm) for almost everything. The current availability issues have made us look into other directions, but that is all too much trouble. Just hoping things will get better in the not too distant future. -- Stef Friends, n.: People who borrow your books and set wet glasses on them. People who know you well, but like you anyway.