An Introduction to 8086 Microprocessor

Slide 2

8086 Features:

• 16-bit Arithmetic Logic Unit

• 20-bit address bus - 220 = 1,048,576 = 1 meg

The address refers to a byte in memory. In the 8088, these bytes come in on

the 8-bit data bus. In the 8086, bytes at even addresses come in on the low

half of the data bus (bits 0-7) and bytes at odd addresses come in on the upper

half of the data bus (bits 8-15).

The 8086 can read a 16-bit word at an even address in one operation and at an

odd address in two operations. The 8088 needs two operations in either case.

The least significant byte of a word on an 8086 family microprocessor is at the

lower address.

Slide 3

Simplified CPU Design:

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