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

Function

The 8284 contains a clock generator capable of a third the frequency of the input clock (up to 8MHz with the 8284A), with sources selectable between an external crystal and clock input. The main clock output consists of a 4.5V (Vcc @ 5V) square 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.

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
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