Texas Instruments TMS320C3x User Manual

Page 270

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Memory Interface Signals

9-4

Table 9–1. Primary Bus Interface Signals

Signal

Type

Description

Value

After Reset

Idle Status

STRB

O/Z

Primary interface access strobe

1

1

R/W

O/Z

Specifies memory read (active high) or write
(active low) mode

1

1

HOLD

I

Hold external memory interface

NA

Ignored

HOLDA

O/Z

Hold acknowledge for external memory interface

1

1

RDY

I

Indicates external primary interface is ready to
be accessed

NA

Ignored

A (23–0)

O/Z

Primary address bus. When the primary bus
address lines are not in high-impedance state
due to HOLD signal, they keep in the last exter-
nal primary bus access.

HI

Address of last external
bus access

D (31–0)

I/O/Z

Primary data bus. These signals go to high-
impedance between write accesses.

HIZ

HIZ

† I

Input

O Output
Z High impedance

‡ NA means not affected.

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