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
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.)
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!