SN74ACT2440

NuBus

™ INTERFACE CONTROLLER

SCHS010 – D3158, OCTOBER 1988 – REVISED JANUARY 1991

POST OFFICE BOX 655303

Copyright

1

Applications

Applications

NuBus

™ Data/Address Interface Devices

With the Addition of the SN74ALS2442

CMOS) 1-

µm Process

Reliability

description

The SN74ACT2440 NuBus

™ Controller handles

NuBus

™ signaling protocol in compliance with

ANSI/IEEE Std 1196-1987. The device allows a

simple

connection

to

the

NuBus

™; typical

configurations include master-only, slave-only,

and master/slave. Additionally, it provides extra status and control lines to facilitate more sophisticated

approaches. With the addition of the SN74ALS2442, slave block transfers can be supported by this device. For

additional details on block transfers, consult the SN74ALS2442 data sheet and the application note titled

Supporting NuBus

™ Block Slave Transfers Using Texas Instruments SN74ACT2440, SN74BCT2420, and

SN74ALS2442.

Figure 1 shows a typical NuBus

™ interface using the ’ACT2440. Data and address buffering is handled via two

SN74BCT2420s. The SN74BCT2420s are BiCMOS buffers designed specifically for supporting NuBus

™

interfacing. The ’ACT2440 provides the buffer control signals needed to directly drive the SN74BCT2420s;

however, in simpler applications, standard SSI and MSI buffers may be used in place of the ’BCT2420s.

The ’ACT2440 is comprised of five major signal groups: byte decode signals, data/address interface-control

signals, master/slave input signals, NuBus

™ card-slot signals, and NuBus™ status signals. Byte decode

determines which type of NuBus

™ cycle is being performed. Data/address interface control provides the

buffering signals required to multiplex and de-multiplex the NuBus

™ data/address lines. The master/slave

inputs control the master- and slave-state machines. The NuBus

™ card-slot signals interface with the NuBus™.

The NuBus

™ status signals indicate the status of the master/slave-state machines and provide buffered

NuBus

™ signals. Refer to Table 1 for additional details.

The SN74ACT2440 is characterized for operation from 0

°C to 70°C.

67

68

28 29

A1

A0

VCC

SIACK

SGNTA

LOCTM1

LOCTM0

NMREQ

GND

MHOLD

LACK

MLREQ

MRDY

NREQ

MDONE

NLOCK

NMSTR

60

59

58

57

56

55

54

53

52

51

50

49

48

47

46

45

44

30

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

RESET

ARB0

GND

ARB1

GND

ARB2

GND

ARB3

GND

VCC

START

ACK

GND

RQST

GND

NMRQ

CLK

31 32 33 34

FN PACKAGE

(TOP VIEW)

87 6 5 4

93

1

2

35 36 37 38 39

66 65

27

64 63 6261

40 41 42 43

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of Texas Instruments

standard warranty. Production processing does not necessarily include

testing of all parameters.

NuBus is a trademark of Texas Instruments Incorporated.

EPIC is a trademark of Texas Instruments Incorporated.