Comments on: Are you, or would you consider, using a 4-bit microcontroller?

By: Lutz

Lutz — Mon, 28 Jul 2014 16:18:37 +0000

Motorola formerly has set ZRHC4 as an most competetive 4bit mcu
however today nobody knows anout that

By: lol

lol — Thu, 30 Jan 2014 03:23:05 +0000

I’ve got one! (in my electric toothbrush):

http://www.youtube.com/watch?v=JJgKfTW53uo

By: B.Z. @LI

B.Z. @LI — Sat, 27 Nov 2010 22:40:26 +0000

The one and only time I used a 4-bit machine was when I was asked to take a prototype engine controller using a Signetics 2650 and port it into a COPS400-based controller. I ended up putting the controller software into several different architectures, all of which could do the job. That COPS400 could string 16 nibbles together with BCD arithmetic operations, giving it some computational capability.

When your entire program runs on-chip and you eliminate the external bus connection, your cost starts dropping and the word length becomes far less relevent. In a high-volume situation, it is the cost of the final custom chip (IP licenses, etc.) that drive the selection. If you are only making a few ten of thousands, then you may want to look at your options. Total cost of operation, from concept to obsolescence.

4-bit sweet spot? Using BCD comes to mind, making it work for cash transactions with 7-segment displays, RFID transactions with LEDs, any small appliance with a clock/timer, locks with keypads, even personal protection such as detecting when you have been scanned at a close distance.

By: Jon Titus

Jon Titus — Thu, 25 Nov 2010 18:24:45 +0000

Plenty of uses for 4-bit MCUs in control and monitoring/reporting applications. I suppose they would work well in microwave ovens, refrigerators, and similar devices. Even good for speed control in some AC motors. By the way, in the ’70′s, Motorola offered a 1-bit processor (no, I am not kidding), the MC14500B. The data bus was one bit wide, but the processor used a 4-bit instruction. Do a Google search for the MC14500B data sheet and you’ll get some interesting information.

By: Rick Hully

Rick Hully — Thu, 25 Nov 2010 16:26:55 +0000

The 4-bit is definitely not dead. We have 211 4 bit MCU’s in our Gopher database.

21 from Atmel
119 from NEC
61 from Renesas
10 from Samsung