
1
P/N:PM0555
REV. 0.9.8, FEB. 14, 2000
1.0 Features
Direct interface to 80188/186 up to 40Mhz.
Integrated 10/100 TP tranceiver on chip to reduce
overall cost
Fully comply to IEEE 802.3u spec.
Best fit in network printer and hub/switch manage-
ment application
A local DMA channel between on-chip FIFOs and
packet memory
Shared memory architecture allow host and
MX98726 to use only one single SRAM
Host DMA can share packet memory with local DMA
with simple hand shake protocol for x188/186 type of
processor
MX98726
SINGLE CHIP 10/100 FAST ETHERNET
CONTROLLER WITH uP INTERFACE
ADVANCED INFORMATION
Support bus size configuration:
- CPU : 8 bits, SRAM: 8 bits
- CPU : 16 bits, SRAM: 8/16 bits
Flexible packet buffer partition and addressing space
for 32k, 64k up to 512 bytes
NWAY autonegociation function to automatically set
up network speed and protocol
3 loop back modes for system level diagnostics
Rich on-chip register set to support a wide variety of
network management functions
Support 64 bits hash table for multicast addressing
Support software EEPROM interface for easy up-
grade of EEPROM content
Support 1K bits and 4K bits EEPROM interface
5V CMOS in 128 PQFP package for minimum board
size application
1.1 Introduction
MX98726 ( Generic MAC , or GMAC ) is a cost effective
solution as a generic single chip 10/100 Fast Ethernet
controller. It is designed to directly interface 80188, 80186
( host ) without glue logic. Two types of memory sharing
schemes are supported, i.e. interleaved and shared mode
to support a variety of applications. Single chip solution
will help reduce system cost not only on the compo-
nents but also the board size. Full NWAY function with
10/100 tranceiver will ease the field installation, simply
plug the chip in and it will connect itself with the best
protocol available.
The interleaved mode allow uP to access SRAM (
packet/host buffer ) through MX98726's local DMA chan-
nel. This way, no extra SRAM interface logic is needed
on the host side. If high performance is desired, then
shared memory mode is another alternative which allow
host to access SRAM on its own by denying SRAM bus
grant to MX98726 using simple hand shake protocol.
Without SRAM bus grant, MX98726 will float its inter-
face connected to the SRAM, therefore host can utilize
its own memory subsystem to conduct its own SRAM
access.
A intelligent built-in SRAM bus arbitor will manage all
the SRAM access requests from host, on-chip transmit
channel and on-chip receive channel. The throughput
of these network channels and MX98726's DMA burst
length can be easily adjusted by option bits on the chip.
These options can help system developers to "fine tune"
a best cost/performance ratio.
MX98726 is also equipped with fast back-to-back trans-
mit capability which allow software to "fire" as many
transmit packets as needed in a single command. Re-
ceive FIFO also allow back-to-back reception. Optional
EEPROM can be used to stored network network ad-
dress and other information. In case cost is really a con-
cern, most configuration options including network ad-
dress can be programmed through uP.