The Intel 8284 is a clock oscillator chip developed primarily for supplying clock signals for the Intel-8086/

8087 The Intel 8087, announced in 1980, was the first floating-point coprocessor for the 8086 line of microprocessors. The purpose of the chip was to speed up floating-point arithmetic operations, such as addition, subtraction, multiplication, di ...

8088 The Intel 8088 ("''eighty-eighty-eight''", also called iAPX 88) microprocessor is a variant of the Intel 8086. Introduced on June 1, 1979, the 8088 has an eight-bit external data bus instead of the 16-bit bus of the 8086. The 16-bit registers ...

8089 The Intel 8089 input/output coprocessor was available for use with the 8086/8088 central processor. It was announced in May 1979, but the price was not available at that time. It used the same programming technique as 8087 for input/output operat ...

series of processors. The commercial variant of the chip comes in 18-pin DIL and 20-pin PLCC packages, and originally was priced at $4.90 USD. The industrial version, rated for the temperatures range of -40 °C to +85 °C was priced at $13.50 USD. The available 82C84A CMOS version was outsourced to Oki Electronic Industry Co., Ltd. The available packaged Intel 82C84A version of 20-pin PLCC in sampling at first quarter of 1986.Ashborn, Jim; "Advanced Packaging: A Little Goes A Long Way", Intel Corporation, Solutions, January/February 1986, Page 2

Function

The 8284 contains a clock generator capable of a third the frequency of the input clock (5 or 8MHz with the 8284A, and 10MHz with the 8284A-1), with sources selectable between an external

crystal A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macros ...

and

clock A clock or chronometer is a device that measures and displays time. The clock is one of the oldest Invention, human inventions, meeting the need to measure intervals of time shorter than the natural units such as the day, the lunar month, a ...

input. The main clock output consists of a 4.5V (Vcc @ 5V) pulse wave at a 33.3% duty cycle, with an additional peripheral clock running at half of the main clock and a 50% duty cycle. Additional logic is provided to accommodate delays to allow for proper system start-up. It has been used in the

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 ...

IBM PC XT The IBM Personal Computer XT (model 5160, often shortened to PC/XT) is the second computer in the IBM Personal Computer line, released on March 8, 1983. Except for the addition of a built-in hard drive and extra expansion slots, it is very simi ...

and

IBM PCjr The IBM PCjr (pronounced "PC junior") was a home computer produced and marketed by IBM from March 1984 to May 1985, intended as a lower-cost variant of the IBM PC with hardware capabilities better suited for video games, in order to compete mor ...

References

{{reflist Input/output integrated circuits Intel chipsets