GENERAL DESCRIPTION
The Am79C976 controller is a highly-integrated 32-bit full-duplex, 10/100-Megabit per second (Mbps) Ethernet controller solution, designed to address high performance system application requirements. It is a flexible bus mastering device that can be used in any application, including network-ready PCs and bridge/router designs. The bus master architecture provides high data throughput and low CPU and system bus utilization. The Am79C976 controller is fabricated with advanced low-power 3.3-V CMOS process to provide low operating current for power sensitive applications.

DISTINCTIVE CHARACTERISTICS
■ Integrated Fast Ethernet controller for the
   Peripheral Component Interconnect (PCI) bus
   — 32-bit glueless PCI host interface
   — Supports PCI clock frequency from DC to
      33 MHz independent of network clock
   — Supports network operation with PCI clock
      from 15 MHz to 33 MHz
   — High performance bus mastering
      architecture with integrated Direct Memory
      Access (DMA) Buffer Management Unit for
      low CPU and bus utilization
   — PCI specification revision 2.2 compliant
   — Supports PCI Subsystem/Subvendor
      ID/Vendor ID programming through the
      EEPROM interface
   — Supports both PCI 3.3-V and 5.0-V signaling
      environments
   — Plug and Play compatible
   — Uses advanced PCI commands (MWI, MRL,
      MRM)
   — Optionally supports PCI bursts aligned to
      cache line boundaries
   — Supports big endian and little endian byte
      alignments
   — Implements optional PCI power management
      event (PME) pin
   — Supports 40-bit addressing (using PCI Dual
      Address Cycles)
■ Media Independent Interface (MII) for
   connecting external 10/100 megabit per second
   (Mbps) transceivers
   — IEEE 802.3-compliant MII
   — Intelligent Auto-Poll™ external PHY status
      monitor and interrupt
   — Supports both auto-negotiable and non auto
      negotiable external PHYs
   — Supports 10BASE-T, 100BASE-TX/FX,
      100BASE-T4, and 100BASE-T2 IEEE 802.3-
      compliant MII PHYs at full- or half-duplex
■ Full-duplex operation supported with
   independent Transmit (TX) and Receive (RX)
   channels
■ Includes support for IEEE 802.1Q VLANs
   — Automatically inserts, deletes, or modifies
      VLAN tag
   — Optionally filters untagged frames
■ Provides optional flow control features
   — Recognizes and transmits IEEE 802.3x MAC
      flow control frames
   — Asserts collision-based back pressure in
      half-duplex mode
■ Provides internal Management Information
   Base (MIB) counters for network statistics
■ Supports PC97, PC98, PC99, and Net PC
   requirements
   — Implements full OnNow features including
      pattern matching and link status wake-up
   — Implements Magic Packet™ mode
   — Magic Packet mode and the physical address
      loaded from EEPROM at power up without
      requiring PCI clock
   — Supports PCI Bus Power Management
      Interface Specification Version 1.1
   — Supports Advanced Configuration and
      Power Interface (ACPI) Specification Version
      1.0
   — Supports Network Device Class Power
      Management Specification Version 1.0
■ Large independent external TX and RX FIFOs
   — Supports up to 4 megabytes (Mbytes)
      external SSRAM for RX and TX frame storage
   — Programmable FIFO watermarks for both
      transmit and receive operations
   — Receive frame queuing for high latency PCI
      bus host operation
   — Programmable allocation of buffer space
      between transmit and receive queues (Continue ...)