Intel 8253

The Intel 8253 and 8254 are Programmable Interval Timers (PITs), which perform timing and counting functions. They were primarily designed for the Intel 8080/8085-processors, but later used in x86-systems. They (or an equivalent circuit embedded in a larger chip) are found in all IBM PC compatibles.

History

The 8253 was used in IBM PC compatibles since their introduction in 1981. In modern times, this PIT is not included as a separate chip in an x86 PC. Rather, its functionality is included as part of the motherboard's southbridge chipset. In some modern chipsets, this change may show up as measurable timing differences in accessing a PIT using the x86 I/O address space. Reads and writes to such a PIT's registers in the I/O address space may complete much faster.

Newer motherboards also include a counter through the Advanced Configuration and Power Interface (ACPI), a counter on the Local Advanced Programmable Interrupt Controller (Local APIC), and a High Precision Event Timer. The CPU itself also provides the Time Stamp Counter (TSC) facility.

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.