Intel 386 User Manual

Page 117

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Intel386™ EX EMBEDDED MICROPROCESSOR USER’S MANUAL

6-4

M/IO#
D/C#
W/R#
REFRESH#

Device pins

Bus Cycle Definition Signals (Memory/IO, Data/Control, Write/Read,
and Refresh):

These four status outputs define the current bus cycle type, as shown
in Table 6-2.

NA#

Device pin

Next Address:

Requests address pipelining.

RD#

Device pin

Read Enable:

Indicates that the current bus cycle is a read cycle and the data bus is
able to accept data.

READY#

Device pin

Ready:

This bidirectional pin is used to terminate the current bus cycle. The
processor drives READY# when LBA# is active. The processor
samples the READY# pin at the falling edge of Phase 2 of T2, T2P or
T2i.

The READY# signal is also used to deassert the WR# signal (Refer to
“Write Cycle” on page 6-16).

WR#

Device pin

Write Enable:

Indicates that the current bus cycle is a write cycle and valid data is
present on the data bus.

Table 6-1. Bus Interface Unit Signals (Sheet 2 of 2)

Signal

Device Pin or

Internal Signal

only

Description

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