FINAL
Am79C940
Media Access Controller for Ethernet (MACE™)
DISTINCTIVE CHARACTERISTICS
s Integrated Controller with Manchester
encoder/decoder and 10BASE-T transceiver
and AUI port
s Arbitrary byte alignment and little/big endian
memory interface supported
s Supports IEEE 802.3/ANSI 8802-3 and Ethernet
standards
s External Address Detection Interface (EADI)
for external hardware address filtering in
bridge/router applications
s 84-pin PLCC and 100-pin PQFP Packages
s Internal/external loopback capabilities
s 80-pin Thin Quad Flat Pack (TQFP) package
available for space critical applications such as
PCMCIA
s JTAG Boundary Scan (IEEE 1149.1) test access
port interface for board level production test
s Modular architecture allows easy tuning to
specific applications
s Digital Attachment Interface (DAI) allows
by-passing of differential Attachment Unit
Interface (AUI)
s High speed, 16-bit synchronous host system
interface with 2 or 3 cycles/transfer
s Individual transmit (136 byte) and receive (128
byte) FlFOs provide increase of system latency
and support the following features:
s Integrated Manchester Encoder/Decoder
s Supports the following types of network
interface:
— AUI to external 10BASE2, 10BASE5 or
10BASE-F MAU
— Automatic retransmission with no FIFO
reload
— DAI port to external 10BASE2, 10BASE5,
10BASE-T, 10BASE-F MAU
— Automatic receive stripping and transmit
padding (individually programmable)
— General Purpose Serial Interface (GPSI) to
external encoding/decoding scheme
— Automatic runt packet rejection
— Internal 10BASE-T transceiver with
automatic selection of 10BASE-T or AUI port
— Automatic deletion of collision frames
— Automatic retransmission with no FIFO
reload
s Direct slave access to all on board
configuration/status registers and transmit/
receive FlFOs
s Direct FIFO read/write access for simple
interface to DMA controllers or l/O processors
s Sleep mode allows reduced power consumption for critical battery powered applications
s 5 MHz-25 MHz system clock speed
s Support for operation in industrial temperature
range (–40°C to +85°C) available in all three
packages
GENERAL DESCRIPTION
The Media Access Controller for Ethernet (MACE) chip
is a CMOS VLSI device designed to provide flexibility
in customized LAN design. The MACE device is specifically designed to address applications where multiple
I/O peripherals are present, and a centralized or system specific DMA is required. The high speed, 16-bit
synchronous system interface is optimized for an external DMA or I/O processor system, and is similar to
many existing peripheral devices, such as SCSI and
serial link controllers.
The MACE device is a slave register based peripheral.
All transfers to and from the system are performed
using simple memory or I/O read and write commands.
In conjunction with a user defined DMA engine, the
MACE chip provides an IEEE 802.3 interface tailored
to a specific application. Its superior modular architecture and versatile system interface allow the MACE
device to be configured as a stand-alone device or
as a connectivity cell incorporated into a larger,
integrated system.
Publication# 16235 Rev: E Amendment/0
Issue Date: May 2000
