AM79C983A datasheet(13/60 Pages) AMD

13 / 60 page

Am79C983A

PRELIMINARY

PIN DESCRIPTION

Pseudo AUI Pins

PDO0-11

Pseudo AUI Data Output

Output/High Impedance

PDO is a single-ended output driver. PDO can be

placed into a high impedance state, allowing multiple

IMR2 devices to connect to a single QuIET device (port

switching). The output data is Manchester encoded.

PDI0-11

Pseudo AUI Receive Data Input

Input

The input data is Manchester encoded.

PCI0-11

Pseudo AUI Collision Input

Input

PAUI port collision data receiver. A 10-MHz square wave

indicates a collision has been detected on that port.

RAUI Port Pins

RDO+, RDO-

Reversible AUI Data Output

Output

RDO is a differential, Manchester output driver.

RDI+, RDI-

Reversible AUI Data Input

Input

RDI is a differential, Manchester receiver.

RCI+, RCI-

Reversible AUI Collision Input

Input/Output

RCI is a differential I/O. As an input, RCI receives a col-

lision indication. As an output, RCI generates a 10-MHz

square wave when a collision is sensed.

Output

This pin is reserved for factory use.

AUI Pins

DO+, DO-

AUI Data Output

Output

AUI port differential driver. Manchester encoded data.

DI+, DI-

AUI Data Input

Input

AUI port differential receiver. Manchester encoded data.

CI+, CI-

AUI Collision Input

Input

AUI port collision differential receiver.

Expansion Bus Pins

DAT

Data

Input/Output/High Impedance

The IMR2 device drives the DAT line with NRZ data

when both REQ and ACK pins are asserted. DAT is an

input if only the ACK signal is asserted. If REQ and ACK

are not asserted, DAT enters a high impedance state.

During collision when JAM is HIGH, DAT is used to sig-

nal a multiport (DAT=0) or single port (DAT=1) condition.

JAM

Jam

Input/Output/High Impedance

This pin is an output if the device is the only active

IMR2 device. An IMR2 device is deﬁned as active when

it has one or more ports receiving or colliding, is in the

state where it is still transmitting data from the internal

FIFO, or is extending a packet to the minimum 96-bit

times. If active, the IMR2 device drives the JAM pin

HIGH to indicate that it is in a Collision state when both

REQ and ACK pins are asserted. JAM is an input if only

the ACK signal is asserted. If REQ and ACK are not as-

serted, JAM enters a high impedance state.

REQ

Request

Output, Active LOW

This pin is driven LOW when the IMR2 device senses

activity. An IMR2 device is deﬁned as ACTIVE when it

has one or more ports receiving or colliding, is in the

state where it is still transmitting data from the internal

FIFO, or is extending a packet to the minimum 96-bit

times. The assertion of this signal signiﬁes that the

IMR2 device requires the DAT and JAM lines to transfer

repeated data and collision status information to other

IMR2 devices.

ACK

Acknowledge

Input, Active LOW

When this signal is asserted by an external arbiter, it

signals to the requesting IMR2 device that it may drive

the DAT and JAM pins. It signals to other IMR2 devices

the presence of valid collision status on the JAM line

and valid data on the DAT line.

AM79C983A Datasheet(PDF) 13 Page - Advanced Micro Devices

AM79C983A Datasheet(HTML) 13 Page - Advanced Micro Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Datasheet Download

Link URL