GENERAL DESCRIPTION
The LAN91C94 is a VLSI Ethernet Controller that combines ISA and PCMCIA interfaces in one chip. LAN91C94 integrates all the MAC and physical layer functions, as well as the packet RAM, needed to implement a high performance 10BASE-T (twisted pair) node. For 10BASE5 (thick coax), 10BASE2 (thin coax), and 10BASE-F (fiber) implementations, the LAN91C94 interfaces to external transceivers via its AUI port. Only one additional IC is required on most applications. The LAN91C94 occupies 16 I/0 locations and no memory space except for PCMCIA attribute memory space.

FEATURES
• ISA/PCMCIA Single-Chip Ethernet Controller
• 4608 Bytes of On-Chip RAM
• Supports IEEE 802.3 (ANSI 8802-3) Ethernet Standards
• Simultasking TM - Early Transmit and Early Receive Functions
• Hardware Memory Management Unit
• Optional Configuration via Serial EEPROM Interface (Jumperless)
• Single +5V Power Supply
• Low Power CMOS Design
• 100 Pin QFP, TQFP and VTQFP Package

Bus Interface
• Direct Interface to ISA and PCMCIA with No Wait States
• Flexible Bus Interface
• 16-Bit Data and Control Paths
• Fast Access Time (40 ns)
• Pipelined Data Path
• Handles Block Word Transfers for Any Alignment
• High Performance Chained ("Back-toBack") Transmit and Receive
• Pin Compatible with LAN91C92 (in ISA mode)
• Flat Memory Structure for Low CPU Overhead
• Dynamic Memory Allocation Between Transmit and Receive
• Buffered Architecture, Insensitive to Bus Latencies (No Overruns/Underruns)
• Supports Boot PROM for Diskless ISA Applications

Network Interface
• Integrates 10BASE-T Transceiver Functions:
   - Driver and Receiver
   - Link Integrity Test
   - Receive Polarity Detection and Correction
• Integrates AUI Interface
• Implements 10 Mbps Manchester Encoding/Decoding and Clock Recovery
• Automatic Retransmission, Bad Packet Rejection, and Transmit Padding
• External and Internal Loopback Modes
• Four Direct Driven LEDs for Status/Diagnostics

Software Drivers
• Uses Certified LAN9000 Drivers Which Operate with Every Major Network Operating System
• Software Driver Compatible with LAN91C92 and LAN91C100 (100 Mbps) Controllers in ISA Mode
• Software Driver Utilizes Full Capability of 32 Bit Microprocessor