4-bit computing is the use of computer architectures in which integers and other data units are 4 bits wide. 4-bit central processing unit (CPU) and arithmetic logic unit (ALU) architectures are those that are based on registers or data buses of that size. A group of four bits is also called a nibble and has 24 = 16 possible values.
20-pin PSOP – NEC D63GS: a 4-bit microcontroller for infrared remote control transmission
16-pin DIP – Intel C4004
Infrared remote control PCB – an infrared remote control transmitter controlled by a NEC D63GS 4-bit microcontroller
National Semiconductor MM5700CA/D bit-serial 4-bit microcontroller
A microprocessor is a computer processor for which the data processing logic and control is included on a single integrated circuit (IC), or a small number of ICs. The microprocessor contains the arithmetic, logic, and control circuitry required to perform the functions of a computer's central processing unit (CPU). The IC is capable of interpreting and executing program instructions and performing arithmetic operations. The microprocessor is a multipurpose, clock-driven, register-based, digital integrated circuit that accepts binary data as input, processes it according to instructions stored in its memory, and provides results as output. Microprocessors contain both combinational logic and sequential digital logic, and operate on numbers and symbols represented in the binary number system.
Texas Instruments TMS1000
Intel 4004
Motorola 6800 (MC6800)
A modern 64-bit x86-64 processor (AMD Ryzen Threadripper 7970X, based on Zen 4, 2023)