AMD-K6-2ESLASH233AMZ datasheet(131/332 Pages) AMD

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Chapter 5

Signal Descriptions

113

22529B/0—January 2000

AMD-K6™-2E Processor Data Sheet

Preliminary Information

5.34

M/IO# (Memory or I/O)

Pin Attribute

Output

Pin Location

T-04

Summary

The processor drives M/IO# during a bus cycle to indicate

whether it is addressing the memory or I/O space. If M/IO# = 1,

the processor is addressing memory or a memory-mapped I/O

port as the result of an instruction fetch or an instruction that

loads or stores data. If M/IO# = 0, the processor is addressing an

I/O port during the execution of an I/O instruction. In addition,

M/IO# is used to define other bus cycles, including interrupt

acknowledge and special cycles. See Table 23 on page 132 for

more details.

Driven and Floated

M/IO# is driven off the same clock edge as ADS# and remains in

the same state until the clock edge on which NA# or the last

expected BRDY# of the cycle is sampled asserted. M/IO# is

driven during memory cycles, I/O cycles, special bus cycles, and

interrupt acknowledge cycles.

M/IO# is floated off the clock edge on which BOFF# is sampled

asserted and off the clock edge on which the processor asserts

HLDA in response to HOLD.

AMD-K6-2E/233AMZ Datasheet(PDF) 131 Page - Advanced Micro Devices