For a college level ecen160 class, my pattern and i made a 4-bit processor this processor is able to do simple logic and display that logic to a lcd display. In this paper, an undergraduate design experience for special purpose 4-bit microprocessor using the skills learned from digital logic design and microprocessors courses is presented the experience started in  by designing the alu using the hardware printed circuit board and we are following it by completing the design by the instruction set architecture and the microprogram code.
An x-bit computer (or cpu) is defined whether the central unites and registers, such as cpu and alu, are in x-bit yet, by his definition, i'm still designing a 4-bit computer and now i'm learning of exactly what parts cpu is made of.
4 bit cpu design description this project is a 4 bit cpu built from ttl counters, latches and gates two, 2716 eproms are used to store the micro-instruction code and two, 2114 static rams are used for program memory 25 ics in all. Related essays: opportunities of sustainable design for interior design construction essay sustainable design for interior design construction essay.
This 4 bit cpu was designed, built and tested without the aid of a logic analyzer or any hardware simulation software i only used a logic probe and an oscilloscope overview of the design this cpu has 16 instructions more instructions could have been implemented but 4 bit instructions means 16 is the limit. For a college level ecen160 class, my pattern and i made a 4-bit processor this processor is able to do simple logic and display that logic to a lcd display we used a. In computer architecture, 4-bit integers, memory addresses, or other data units are those that are 4 bits wide also, 4-bit cpu and alu architectures are those that are based on registers , address buses , or data buses of that size.
The data bus is 4 bits wide, as one should expect for a 4-bit cpu the program bus is 8 bits wide: 4 bits for the instruction opcode, and 4 bits for the immediate operand or high bits of the target address. At the top left of the schematic are the three chips pertaining to the execution of the current instruction the fetch register is a ‘377, an 8-bit register that holds the current instruction opcode in the high 4 bits and instruction or address data in the low 4 bits alu flags are stored in the 4-bit flags register, a ‘173. There were two four bit registers required in the final design with eight bit wide memory addresses used for program and data memory the first design specification was that of indexed memory address arithmetic this causes delay with the processor but as it is only a 4-bit cpu, the delay is negligible.
How to build your own discrete 4-bit alu august 18, 2016 by robin mitchell learn about the heart of a simple 4-bit cpu, the alu (arithmetic logic unit), and how to build one, yourself. Overall design the completed computer is shown below the central three boards (alu, main board and control) make up what is commonly thought of as a computer processor, or central processing unit (cpu)the processor takes instructions and data from the memory-input/output, processes them, and puts data back into the memory-input/output.