18-11-2020 | | By Robin Mitchell
Recently, the Intel 4004 turned 49 years old, and next year will see the world’s first microprocessor turn 50. What was the Intel 4004, how did technology change with each progressive update, and how has the Intel 8051 and Z80 been able to remain relevant even till today?
Intel is a company that has global brand recognition for high-end processors that utilise a complex instruction set architecture with brand names including Xenon, Celeron, and the i (i3, i5, and the i7) range. However, while many who know who Intel are today, the vast majority of Intel users are unaware of Intel’s origins, what products they used to produce, and how they became the world’s most formidable processor designer and manufacturer.
Intel was founded in 1968 by Gordon E. Moore, the individual responsible for Moore’s Law), and Robert Noyce who was the co-inventor of the integrated circuit. Within two years of establishment, Intel became a publicly-traded company thanks to its recognition of the importance of semiconductors and how they would change the electronics industry.
Intel’s first product was the 3101, a 64-bit SRAM which was not only faster than its competitors but provided a superior alternative to magnetic rope-core memory of the time. Products that followed the 3101 SRAM chip also included 1024-bit ROM, a MOSFET SRAM chip with 256 bits of storage, and the first commercially available DRAM chip that provided 1024 bits of storage.
The development of logic circuits and memory caught the attention of Nippon Calculating Machine Corporation who wanted to create a new line of electronic calculators. After approaching Intel to ask for 12 custom chips, Intel in return suggested that only four custom chips should be used in the chipset, a ROM, a RAM, a shift register, and the CPU. This design would not only reduce the number of total chips; it would also allow for these components to be used in other generic systems.
The chipset series, called the MCS-4, was put into development, and Federico Faggin designed the CPU. The resulting chipset proved successful for the Nippon Calculating Machine Corporation, but when Intel asked to purchase the rights of the MCS-4, they agreed, and from there Intel announced their new chipset in Electronics News on November 15th 1971. Unknowing to the original rights owners, this would prove to be one of the best deals ever made by Intel, or by any company for that matter.
After the 4004
The success of the Intel 4004 laid in its ability to be generic, and thus be able to produce any computational machine that a designer could think of. While the Intel 4004 was designed to be used with the rest of the chipset, it was the processing capability of the Intel 4004 that made it popular. From there, Intel continued its development with CPUs and gradually increased the speed and capabilities of their processors.
Intel’s first 8-bit CPU, the Intel 8008, sparked a whole new range of processors that demonstrated how increasing the bit-width not only dramatically increases the CPUs capabilities but also greatly expands its memory size. The Intel 8008 eventually led to the Intel 8080 and from there the Intel 8085 which marked the end of 8-bit processors produced by Intel.
The Intel 8086, which was the successor of the Intel 8085, was Intel’s first 16-bit processor that marked the start of the X86 architecture. All Intel processors after the Intel 8086 utilise the same basic architecture which has allowed designers to move to the next generation of processors with little need to change the underlying code that their programs are written in.
Intel’s history stretches a long time, and most products designed by Intel before 2010 are no longer in circulation. However, two products, in particular, are still being manufactured, the Intel MCS-51 and the Zilog Z80. Before we look into why these are still being manufactured, it should be stated that the Z80 is a product developed by Zilog and not Intel, but the reason why it is included here is that its designer, Federico Faggin, was the individual who also designed and developed the Intel 4004.
The Intel MCS-51 is often referred to as the 8085, and there are many microcontrollers today that utilise the 8085 as their CPU core including those produced by Atmel, Infineon, NXP, Siemens, and Texas Instruments. One of the reasons for the MCS-51 continued popularity comes from its power and simplicity; the MCS-51 can be used in a wide range of low-end applications and control hardware while being small enough to be combined with other hardware such as an IP core in an ASIC or FPGA.
The Z80 is a very famous 8-bit processor that is compatible with the 8080, and its popularity comes from its strong, rich instruction set, many registers, and ease of programming. The manufacturing of the Z80 processor is also important from a maintenance perspective; the popularity of the Z80 saw it used in many hundreds of thousands of key systems around the world, and many of these systems are still operational. Thus, it is important that the Z80 is still available so that these systems can be repaired.
Intel has come along way from developing simple 4-bit CPUs and is now a dominate force in the semiconductor industry. While most of their products are no longer manufactured, it brings peace to mind that some of their products are still being manufactured, and that the world of CPUs is almost half a century old!