Sources
- Intel, “50 Years Ago: Celebrating the Influential Intel 8080” - 2024-12-16
- Intel, “Intel 8080 Microcomputer Systems User’s Manual” - 1975-09
Background
- It was developed in 1974 by Frederico Faggin
- Intel 8080 is the first actual general-purpose microprocessor
- Intel 4004 and 8008 were later used for general purpose applications but they were not designed to be used that way
- The inability of the chips prior to the 8080 to handle greater scale and complexity applications engendered the development of the 8080
- Specifications
- 8-bit
- 40-pin configuration for improved component connection
- A single-chip microprocessor
- Notable improvements to the 8008 and 4004
- Is better at connecting to other components due to its 40-pin configuration (in contrast to the 18-pin configuration of the 8008)
- Increased performance and flexibility: it can execute 290,000 operations per second, which is 10 times more than that of the 8008; unlike the previous processors which had designs tailored to meet the needs of their investors, the 8080 allowed its customers to freely customize it according to their own needs.
- Early implementations of the 8080:
- Hugin Model 150 - an electronic cash register
- MITS Altair 8800 - one of the earliest personal computers
- Gun Fight - the first commercially-available arcade game that used a microprocessor instead of discrete logic.
Memory Map
INFO
Memory Map should show the allocation of the memory devices
Importance of Memory
- It stores Instructions and Data
- Instructions direct the activities of the CPU. When a group of instructions are logically related, they are make up what is called a Program.
- Data are pieces of information processed/manipulated by the CPU
- Computers use a set of instructions arranged in a logically determined sequence to initiate processing actions and generate meaningful results.
Parts of the Intel 8080 Memory
- Consists of a Read Only Memory (ROM) and a Read/Write Memory (RAM) for program and data storage
- ROM
- A device that stores data in a Program format or other types that can only be read from; hence Read Only.
- It is non-volatile and therefore it can still keep the information despite the power being removed.
- RAM
- Is a device that stores data, including a program, active look-up tables, temporary values or external stacks.
- In contrast to ROMs, data can be written in RAM and, as such, they can both read and write information. Besides this, RAM also cannot retain their stored data when power is removed.
- The typical memory system has a memory array of 8K bytes of ROM storage (through four Intel 8316As) and 512 bytes of RAM storage (through 8111 static RAMs). See figure at 3-7
- For larger systems, more buffers—an 8216/8212—and decoders—8205—are added for producing chip selects.
- Its memory is organized into Bytes (8-bit quantities). The bytes each have unique 16-bit addresses that pertain to their sequential position in memory.
- The 8080 can directly address up to 65,536 bytes of memory.