INTEL 8008

General description

The Intel 8008, introduced in 1972, was a groundbreaking 8-bit microprocessor that marked Intel’s entry into the microcomputing era. With approximately 3,500 transistors and an 8-bit data bus, it operated at 800 kHz. While not as widely recognized as its successors, the 8008 laid the foundation for the evolution of microprocessors, serving as a pivotal step in the advancement of computing technology.
  • Instruction Cycle Time – 1.25 µS with 8008·1 or 20 µS with 8008
  • Directly Addresses 16K x 8 Bits of Memory (RAM, ROM, or S.R.)
  • Interrupt Capability
  • 48 Instructions, Data Oriented
  • Address Stack Contains 8 14·Bit Registers (Including Program Counter) Which Permit Nesting of Subroutines Up to 7 Levels

The Intel® 8008 is a single chip MOS 8-bit parallel central processor unit (CPU) for the MCS-8 microcomputer system. This CPU contains 6 8-bit data registers, an 8-bit accumulator, 2 8-bit temporary registers, 4 flag bits (carry, zero, sign, parity), and an 8-bit parallel binary arithmetic unit which implements addition, subtraction, and logical operations. A memory stack containing a 14-bit program counter and 7 14-bit words is used internally to store program and subroutine addresses. The 14-bit address permits the direct addressing of 16K words of memory (any mix of RAM, ROM, or S.R.).

The instruction set of the 8008 consists of 48 instructions including data manipulation, binary arithmetic, and jump to subroutine. The normal program flow of the 8008 may be interrupted through the use of the interrupt control line. This allows the servicing of slow I/O peripheral devices while also executing the main program. The ready command line synchronizes the 8008 to the memory cycle allowing any type or speed of semiconductor memory to be used.


Historical outline

The Intel 8008, introduced in 1972, was Intel’s pioneering 8-bit microprocessor designed by Ted Hoff. As the first microprocessor crafted for general-purpose computing, it marked a significant milestone in the advancement of microcomputing technology.

In the early 1970s, Intel’s recognition of microprocessors’ transformative potential led to the inception of the Intel 8008 microprocessor. Engineer Ted Hoff’s groundbreaking vision for a versatile microprocessor laid the groundwork for a new era in computing.

In April 1972, Intel introduced the Intel 8008, marking a pivotal moment as the first microprocessor designed for general-purpose computing. Operating at 800 kHz, the 8008 featured 8-bit processing, making it a pioneering step toward compact and efficient computing solutions.

While initial applications faced challenges due to limited memory and processing capabilities, the Intel 8008’s debut marked the inception of microcomputing’s evolution. Its success propelled further microprocessor advancements and spurred interest in the potential of these devices.

The Intel 8008’s impact resonates not only through its technical achievements but also its role as a catalyst for change. It paved the way for more sophisticated processors like the Intel 8080, influencing the course of computing history and setting the stage for the modern technological landscape we inhabit today.

Emulation and Development Tools

The Intel Intellec 8 was a groundbreaking microcomputer aimed at facilitating software development and testing. Combining a dedicated hardware unit comprising a hexadecimal keyboard and LED display with a suite of software tools like a monitor program, assembler, and simulator, the Intellec 8 played a pivotal role in shaping the early microprocessor landscape.
  • The Intel Intellec8 /Mod8, introduced in 1974, was a revolutionary microcomputer system designed to aid in software development and testing. Its hardware unit included a hexadecimal keyboard and LED display, providing a hands-on approach to programming and debugging. Complemented by essential software tools like a monitor program, assembler, and simulator, the Intellec 8 offered a comprehensive solution for developers.

    The system’s interactive design allowed programmers to manually input machine code, stepping through instructions and observing the processor’s behavior. Its simulator enabled software testing without the need for physical hardware. Additionally, the Intellec 8 featured an EPROM burner, crucial for programming microprocessor memory.

    Widely utilized within Intel, the Intellec 8 had a lasting impact beyond the company, influencing microprocessor-based development industry-wide. It played a key role in nurturing the growth of microcomputing technology during its foundational years. With its user-friendly interface and robust toolset, the Intellec 8 remains an emblem of the early microcomputer era’s innovation.

Applications for the 8008 Processor

The Mark-8 computer, designed by Jonathan Titus in 1974, was a pioneering creation in the realm of personal computing. Sold in kit form, it was an early example of a computer aimed at hobbyists and electronics enthusiasts.
  • The Mark-8  computer powered by the Intel 8008 microprocessor, the Mark-8 featured 256 bytes of memory, a hexadecimal keypad for manual input, and a 20-character LED display for output. Its schematics and plans were detailed in the July 1974 issue of Radio-Electronics magazine, which led to its widespread replication and experimentation by the DIY computer community. The Mark-8’s impact on the nascent computer industry is notable as it contributed to the momentum that eventually led to the personal computer revolution.