X86C64

2

PIN DESCRIPTIONS

Multiplexed low-order addresses and data. The ad-

dresses flow into the device while

AS is LOW. After AS

transitions from a LOW to HIGH the addresses are

latched. Once the addresses are latched these pins input

data or output data depending on

DS, R/W, and CE.

High order addresses flow into the device when

and are latched when

AS goes HIGH.

Chip Enable (CE)

The Chip Enable input must be HIGH to enable all read/

write operations. When CE is LOW and

AS is HIGH, the

X86C64 is placed in the low power standby mode.

Data Strobe (

DS)

When used with a Z8 the

DS input is tied directly to the

DS output of the microcontroller.

Read/Write (R/

W)

When used with a Z8 the R/

W input is tied directly to the

R/

W output of the microcontroller.

Address Strobe (

AS)

Addresses flow through the latches to address decoders

when

AS is LOW and are latched when AS transitions

from a LOW to HIGH.

Device Select (

SEL)

Write Control (

WC)

The Write Control allows external circuitry to abort a

page load cycle once it has been initiated. This input is

useful in applications in which a power failure or proces-

sor RESET could interrupt a page load cycle. In this

case, the microcontroller might drive all signals HIGH,

after Read/Write (R/

W) goes HIGH, the write cycle will

be aborted.

When

enabled to perform write operations. When

WC is HIGH

normal read operations may be performed, but all at-

tempts to write to the device will be disabled.

PIN CONFIGURATION

3819 FHD F01

PIN NAMES

Symbol

Description

AS

Address Strobe

Address Inputs/Data I/O

Address Inputs

DS

Data Strobe Input

R/

W

Read/Write Input

CE

Chip Enable

WC

Write Control

SEL

Ground

Supply Voltage

3819 PGM T01

NC

A12

NC

NC

WC

SEL

A/D0

A/D1

A/D2

A/D3

A/D4

VSS

1

2

3

4

5

6

7

8

9

10

11

12

24

23

22

21

20

19

18

17

16

15

14

13

VCC

R/W

AS

A8

A9

A11

DS

A10

CE

A/D7

A/D6

A/D5

X86C64

DIP/SOIC