Intel 80486SX

Intel's i486SX was a modified Intel 486DX microprocessor with its floating-point unit (FPU) disabled. It was intended as a lower-cost CPU for use in low-end systems. Computer manufacturers that used these processors include Packard Bell, Compaq, ZEOS and IBM.

In the early 1990s, common applications did not need or benefit from an FPU. Among the rare exceptions were CAD applications, which could often simulate floating point operations in software, but benefited from a hardware floating point unit immensely. Intel wanted to provide a lower cost i486 CPU for system integrators, but without sacrificing the better profit margins of a "full" i486. This was accomplished through a debug feature called Disable Floating Point (DFP), by grounding a certain bond wire in the CPU package. The i486SX was introduced in mid-1991, 18 months after the i486DX. Later (late 1992) versions of the i486SX had the FPU entirely removed for cost cutting reasons.

Some systems allowed the user to upgrade the i486SX to a CPU with the FPU enabled. The upgrade was shipped as the i487, which was a full blown i486DX chip with an extra pin. The extra pin prevents the chip from being installed incorrectly. The NC# pin, one of the standard 168 pins, was used to shut off the i486SX. Although i486SX devices were not used at all when the i487 was installed, they were hard to remove because the i486SX was typically installed in non-ZIF sockets or in a plastic package that was surface mounted on the motherboard.

Intel

Coordinates: 37°23′16.54″N 121°57′48.74″W / 37.3879278°N 121.9635389°W / 37.3879278; -121.9635389

Intel Corporation (better known as Intel) is an American multinational technology company headquartered in Santa Clara, California. Intel is one of the world's largest and highest valued semiconductor chip makers, based on revenue. It is the inventor of the x86 series of microprocessors, the processors found in most personal computers. Intel supplies processors for computer system manufacturers such as Apple, Samsung, HP and Dell. Intel also makes motherboard chipsets, network interface controllers and integrated circuits, flash memory, graphics chips, embedded processors and other devices related to communications and computing.

Intel Corporation was founded on July 18, 1968 by semiconductor pioneers Robert Noyce and Gordon Moore and widely associated with the executive leadership and vision of Andrew Grove, Intel combines advanced chip design capability with a leading-edge manufacturing capability.

Intel (disambiguation)

Intel, short for Intel Corporation, is the world's largest semiconductor company.

Intel may also refer to:

See also

Intel 80188

The Intel 80188 microprocessor was a variant of the Intel 80186. The 80188 had an 8-bit external data bus instead of the 16-bit bus of the 80186; this made it less expensive to connect to peripherals. The 16-bit registers and the one megabyte address range were unchanged, however. It had a throughput of 1 million instructions per second.

Description

Features and performance

The 80188 series was generally intended for embedded systems, as microcontrollers with external memory. Therefore, to reduce the number of chips required, it included features such as clock generator, interrupt controller, timers, wait state generator, DMA channels, and external chip select lines. While the N80188 was compatible with the 8087 numerics co-processor, the 80C188 was not. It didn't have the ESC control codes integrated.

The initial clock rate of the 80188 was 6 MHz, but due to more hardware available for the microcode to use, especially for address calculation, many individual instructions ran faster than on an 8086 at the same clock frequency. For instance, the common register+immediateaddressing mode was significantly faster than on the 8086, especially when a memory location was both (one of the) operand(s) and the destination. Multiply and divide also showed great improvement, being several times as fast as on the original 8086 and multi-bit shifts were done almost four times as quickly as in the 8086.