Intel 8255

The Intel 8255 (or i8255) Programmable Peripheral Interface (PPI) chip is a peripheral chip originally developed for the Intel 8085 microprocessor, and as such is a member of a large array of such chips, known as the MCS-85 Family. This chip was later also used with the Intel 8086 and its descendants. It was later made (cloned) by many other manufacturers. It is made in DIP 40 and PLCC 44 pins encapsulated versions.

Similar chips

The 8255 is used to give the CPU access to programmable parallel I/O, and is similar to other such chips like the MOS Technology 6522 (Versatile Interface Adapter) and the MOS Technology CIA (Complex Interface Adapter) all developed for the 6502 family. Other such chips are the 2655 Programmable Peripheral Interface from the Signetics 2650 family of microprocessors, the Motorola 6820 PIA (Peripheral Interface Adapter) from the Motorola 6800 family, the Western Design Center WDC 65C21, an enhanced 6520, and many others.

However, most often the functionality 8255 offered is now not implemented with the 8255 chip itself any more, but is embedded in a larger VLSI chip as a subfunction. The 8255 chip itself is still made, and is sometimes used together with a micro controller to expand its I/O capabilities.

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.