GENERAL DESCRIPTION
The Am79C971 controller is a single-chip 32-bit full-duplex, 10/100-Megabit per second (Mbps) highly integrated Ethernet system 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 in the system and low CPU and system bus utilization. The Am79C971 controller is fabricated with AMD’s advanced low-power Complementary Metal Oxide Semiconductor (CMOS) process to provide low operating and standby current for power sensitive applications.

DISTINCTIVE CHARACTERISTICS
■ Single-chip Fast Ethernet controller for the
   Peripheral Component Interconnect (PCI) local
   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 2.1 compliant
   — Supports PCI Subsystem/Subvendor ID/
      Vendor ID programming through the
      EEPROM interface
   — Supports both PCI 5.0-V and 3.3-V signaling
      environments
   — Plug and Play compatible
   — Supports an unlimited PCI burst length
   — Big endian and little endian byte alignments
      supported
■ Integrated 10BASE-T and 10BASE-2/5 (AUI)
   Physical Layer Interface
   — Single-chip IEEE/ANSI 802.3, IEC/ISO 8802-3
      and Blue Book Ethernet-compliant solution
   — Automatic Twisted-Pair receive polarity
      detection and correction
   — Internal 10BASE-T transceiver with Smart
      Squelch to Twisted-Pair medium
   — IEEE 802.3-compliant auto-negotiable
      10BASE-T interface
■ Supports General Purpose Serial Interface (GPSI)
■ Media Independent Interface (MII) for
   connecting external 10- or 100-Megabit per
   second (Mbps) transceivers
   — IEEE 802.3-compliant MII
   — Intelligent Auto-Poll™ external PHY status
      monitor and interrupt
   — Includes intelligent on-chip Network Port
      Manager that provides auto-port selection
      between MII, on-chip 10BASE-T port, and AUI
      without software support
   — 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 (Continue ...)