The NEAT chipset (the acronym standing for "New Enhanced AT") is a 4 chip VLSI implementation (including the 82C206 IPC) of the control logic used in the

IBM PC compatible An IBM PC compatible is any personal computer that is hardware- and software-compatible with the IBM Personal Computer (IBM PC) and its subsequent models. Like the original IBM PC, an IBM PC–compatible computer uses an x86-based central p ...

PC/AT The IBM Personal Computer AT (model 5170, abbreviated as IBM AT or PC/AT) was released in 1984 as the fourth model in the IBM Personal Computer line, following the IBM PC/XT and its IBM Portable PC variant. It was designed around the Intel 802 ...

computers. It consists of the 82C211 CPU/Bus controller, 82C212 Page/Interleave and EMS Memory controller, 82C215 Data/Address buffer, and 82C206 Integrated Peripherals Controller (IPC). NEAT, official designation CS8221, was developed by

Chips and Technologies Chips and Technologies, Inc. (C&T), was an early fabless semiconductor company founded in Milpitas, California, in December 1984 by Gordon A. Campbell and Dado Banatao. Its first product, announced September 1985, was a four chip Enhanced Graph ...

History

The NEAT chipset descended from the first chipset that C&T had developed for IBM XT-compatible systems, which is based around the 82C100 "XT controller" chip. 82C100 incorporates the functionality of what had been, until its invention, discrete TTL chips on the XT's

mainboard A motherboard, also called a mainboard, a system board, a logic board, and informally a mobo (see "Nomenclature" section), is the main printed circuit board (PCB) in general-purpose computers and other expandable systems. It holds and allow ...

, namely: * 8284 clock generator * 8288

bus A bus (contracted from omnibus, with variants multibus, motorbus, autobus, etc.) is a motor vehicle that carries significantly more passengers than an average car or van, but fewer than the average rail transport. It is most commonly used ...

controller * 8254

Programmable Interval Timer In computing and in embedded systems, a programmable interval timer (PIT) is a counter that generates an output signal when it reaches a programmed count. The output signal may trigger an interrupt. Common features PITs may be one-shot or periodi ...

* 8255 parallel I/O interface *

8259 The Intel 8259 is a programmable interrupt controller (PIC) designed for the Intel 8085 and 8086 microprocessors. The initial part was 8259, a later A suffix version was upward compatible and usable with the 8086 or 8088 processor. The 8259 comb ...

Programmable Interrupt Controller In computing, a programmable interrupt controller (PIC) is an integrated circuit that helps a microprocessor (or CPU) handle interrupt requests (IRQs) coming from multiple different sources (like external I/O devices) which may occur simultane ...

* 8237 DMA controller * 8255 Programmable

Peripheral A peripheral device, or simply peripheral, is an auxiliary hardware device that a computer uses to transfer information externally. A peripheral is a hardware component that is accessible to and controlled by a computer but is not a core compo ...

Interface Interface or interfacing may refer to: Academic journals * ''Interface'' (journal), by the Electrochemical Society * '' Interface, Journal of Applied Linguistics'', now merged with ''ITL International Journal of Applied Linguistics'' * '' Inter ...

(PPI) *DRAM/SRAM controller *XT Keyboard controller

IBM PC The IBM Personal Computer (model 5150, commonly known as the IBM PC) is the first microcomputer released in the List of IBM Personal Computer models, IBM PC model line and the basis for the IBM PC compatible ''de facto'' standard. Released on ...

compatibility is provided by C&T's 82C206 Integrated Peripheral Controller (IPC), introduced by C&T in 1986. This chip, like its predecessor the 82C100, provides equivalent functionality to the TTL chips on the

's mainboard, namely: * 82284 clock generator * 82288

controller * 8254

*two

Programmable Interrupt Controllers *two 8237 DMA controllers *74LS612 Memory Mapper chip * MC146818

NVRAM Non-volatile random-access memory (NVRAM) is random-access memory that retains data without applied power. This is in contrast to dynamic random-access memory (DRAM) and static random-access memory (SRAM), which both maintain data only for as l ...

/ RTC chip NEAT CS8221's predecessor, called CS8220, requires five chips ( buffers and

memory controller A memory controller, also known as memory chip controller (MCC) or a memory controller unit (MCU), is a digital circuit that manages the flow of data going to and from a computer's main memory. When a memory controller is integrated into anothe ...

s) for a virtually complete motherboard, while NEAT requires four, and added support for separate

ISA bus Isa or ISA may refer to: Places * Isa, Amur Oblast, Russia * Isa, Kagoshima, Japan * Isa, Nigeria * Isa District, Kagoshima, former district in Japan * Isa Town, middle class town located in Bahrain * Mount Isa, Queensland, Australia * Mou ...

clocks. The eventual successor to the NEAT chipset, 82C235 Single Chip AT (SCAT), amalgamates all of the chips of the NEAT chipset into a single chip.82C235 Single Chip AT (SCAT)
Datasheet

Other manufacturers

Other manufacturers produced equivalent chips. OPTi, for example, produced a two-chip "AT controller" chipset comprising the OPTi 82C206 and 82C495XLC, which is found in many early

80486 The Intel 486, officially named i486 and also known as 80486, is a microprocessor introduced in 1989. It is a higher-performance follow-up to the Intel 386. It represents the fourth generation of binary compatible CPUs following the 8086 of 19 ...

and

Pentium Pentium is a series of x86 architecture-compatible microprocessors produced by Intel from 1993 to 2023. The Pentium (original), original Pentium was Intel's fifth generation processor, succeeding the i486; Pentium was Intel's flagship proce ...

AT-compatible machines. The OPTi 82C206 is pin and function compatible with C&T's 82C206. The 82C495XLC incorporates the additional memory controller and shadow RAM support.

References

{{reflist IBM PC compatibles Chipsets