Intel 8284

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The Intel 8284A situated on a motherboard next to a crystal oscillator. Intel 8284A.jpg
The Intel 8284A situated on a motherboard next to a crystal oscillator.
Pinout 8284 Intel 8284.svg
Pinout 8284

The Intel 8284 is a clock oscillator chip developed primarily for supplying clock signals for the Intel-8086/8087/8088/8089 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. [1] [2] [3] The industrial version, rated for the temperatures range of -40 °C to +85 °C was priced at $13.50 USD. [4] The available 82C84A CMOS version was outsourced to Oki Electronic Industry Co., Ltd. [5] The available packaged Intel 82C84A version of 20-pin PLCC in sampling at first quarter of 1986. [6]

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 and clock 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, IBM PC XT and IBM PCjr.

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Intel 8282

The Intel 8282 is an 8-bit latch, which was developed primarily for the Intel-8086/8087/8088/8089-processors. The component comes in 20-pin DIL package. It was licensed to companies such as NEC and Siemens. With the ROM-less versions of the MCS-48 and MCS-51 microcontroller compact systems with external ROM / EPROM can be realized. The 8282 can also be used in 8080/8085-systems replacing the 8212. If OE is connected to GND, the chip is selected. STB (Strobe) is connected to the pin ALE of the processor and takes over the address data from the multiplexed address-/databus. The 8283 has the same functionality, but the data is inverted. In 1980 the Intel 8282 and I8282 version was available for 5.55 USD and 16.25 USD in quantities of 100 respectively.

Intel 8283

The Intel 8283 is an 8-bit latch, which was developed primarily for the Intel-8086/8087/8088/8089-processors. The component comes in 20-pin DIL package. It was licensed i.e. to NEC and Siemens. If OE connected to GND, the chip is selected. STB (Strobe) is connected to the pin ALE of the processor and takes over the address data from the multiplexed address-/databus. The incoming data is inverted – as opposed to the 8282. The Intel 8283 and I8283 version was available for US$5.55 and $16.25 in quantities of 100 respectively.

Intel 8288

The Intel 8288 is a bus controller designed for Intel 8086/8087/8088/8089. The chip is supplied in 20-pin DIP package. The 8086 operate in maximum mode, so they are configured primarily for multiprocessor operation or for working with coprocessors. Necessary control signals are generated by the 8288. It was used in the IBM PC, XT and its clones. IBM PC AT used its successor Intel 82288.

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References

  1. Intel Corporation, "The 8086 Family: Concepts and realities", Intel Preview Special Issue: 16-Bit Solutions, May/June 1980, Page 19
  2. alldatasheet.com. "8284 Datasheet". pdf1.alldatasheet.com. Retrieved 2016-11-26.
  3. alldatasheet.com. "UPB8284AD Datasheet". pdf1.alldatasheet.com. Retrieved 2016-11-26.
  4. Intel Corporation, "8086 Available for industrial environment", Intel Preview Special Issue: 16-Bit Solutions, May/June 1980, Page 29
  5. Intel Corporation, "NewsBit: Intel Licenses Oki on CMOS Version of Several Products", Solutions, July/August 1984, Page 1.
  6. Ashborn, Jim; "Advanced Packaging: A Little Goes A Long Way", Intel Corporation, Solutions, January/February 1986, Page 2