Electronics > Microcontrollers
How dead are 4bit MCUs?
gnuarm:
I have found a very small number of 4bit MCUs still on the market, but not as many as I expected. Aren't they still used in coffee makers, remote controls, microwave ovens, toys, etc?
I remember talking to a guy who designed toys, and he said they would review his designs and if there was a resistor that was not absolutely essential, they would remove it to save the 0.1 cents.
Then there's also the power issue. I would expect a 4 bit MCU to be more power thrifty than an 8 bit MCU, doing the very simple tasks these parts would be used for. But... I don't know if this would be significant. Even in a remote control, it sits idle 99.99% of the time, then the LED draws 20 mA for a brief moment.
Anyone here using 4 bit microcontrollers?
BTW, I tried searching on "4 bit", but the search requires at least 2 characters in every word and I guess it sees "4" as a word.
gnuarm:
--- Quote from: edavid on June 12, 2022, 02:29:10 pm ---
--- Quote from: gnuarm on June 12, 2022, 02:10:10 pm ---I have found a very small number of 4bit MCUs still on the market, but not as many as I expected. Aren't they still used in coffee makers, remote controls, microwave ovens, toys, etc?
I remember talking to a guy who designed toys, and he said they would review his designs and if there was a resistor that was not absolutely essential, they would remove it to save the 0.1 cents.
--- End quote ---
8 bit microcontrollers are usually pad limited these days.
--- End quote ---
What process node are the inexpensive MCUs being built on? Low priced products are often made on obsolete processes because the equipment is essentially free, fully amortized. Then there's the power issues. MCUs are often used in very low power applications. I believe it was around 90nm where the static power got to be very significant compared to the dynamic. Later geometries focused on power and so got better by trading off improvements in speed.
--- Quote ---
--- Quote ---BTW, I tried searching on "4 bit", but the search requires at least 2 characters in every word and I guess it sees "4" as a word.
--- End quote ---
This search worked fine:
https://www.google.com/search?q=%224+bit%22+microcontroller
--- End quote ---
I was talking about the search here, in eevblog.
But the Google search, while "working fine", doesn't pull up many makers of 4bit chips.
jpanhalt:
Here are the first two of several Google hits:
https://www.emmicroelectronic.com/sites/default/files/products/datasheets/em6607_ds.pdf
https://www.electronics-lab.com/bit4-is-a-4bit-microcontroller-fully-programmable-with-only-three-buttons/
I searched on 4(four) bit here, including some permutations, and got nothing.
gnuarm:
--- Quote from: edavid on June 12, 2022, 02:53:57 pm ---
--- Quote from: gnuarm on June 12, 2022, 02:50:15 pm ---I was talking about the search here, in eevblog.
But the Google search, while "working fine", doesn't pull up many makers of 4bit chips.
--- End quote ---
https://www.google.com/search?q=%224+bit%22+microcontroller+site:eevblog.com
--- End quote ---
Thanks, I hadn't thought of that. But it still doesn't pull up anything useful specifically. I guess I'm looking for someone who uses 4-bit MCUs and knows of various suppliers of 4 bit MCUs that may not show up on Google's radar. I've found two myself.
http://upt-ic.com/en/products.aspx?id=1
https://www.tritan.com.tw/en/Products/1/1141/4-bit-OTP-MCU
Neither site provides data sheets with any ease.
gnuarm:
--- Quote from: jpanhalt on June 12, 2022, 03:05:54 pm ---Here are the first two of several Google hits:
https://www.emmicroelectronic.com/sites/default/files/products/datasheets/em6607_ds.pdf
https://www.electronics-lab.com/bit4-is-a-4bit-microcontroller-fully-programmable-with-only-three-buttons/
I searched on 4(four) bit here, including some permutations, and got nothing.
--- End quote ---
I know of EM Micro. I haven't gotten a quote from them, but they don't seem to be cheaper than the 8 bit devices. Someone has pointed to an 8 bit device that is only $0.05 at LCSC, Padauk PMS150C. It can be run at 5V. So even if production is 1E6 units, I'm wondering if a 4-bit MCU is useful. Can the price be much lower?
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