12 C HAPTER 1: I NTRODUCTIONHardware FeaturesInteroperability Operates with existing Ethernet equipmentCompliance with PCI LocalBus Specification Version 2.0and 2.1Compatible with a 32- or 64-bit, 33/66 MHzPCI bus master slot. As a bus master NIC, the NICrequests access to the PCI bus instead of waiting tobe polled by the host. An innovative DMA algorithmenables the 3C985B-SX server NIC to automaticallylearn and conform to a particular host’s PCI busand memory system requirements, maximizingperformance and host efficiency.Full-duplex Gigabit EthernetinterfaceIEEE 802.3zFrame-based flow control IEEE 802.3xGigabit Ethernetfiber interface62.5/125 μm or 50/125 μm multimode fiber, using aduplex SC connectorAdaptive interrupt frequency The 3C985B-SX server NIC driver intelligently adjustshost interrupt frequency based on traffic conditionsto increase overall application throughput. In lighttraffic, the NIC driver interrupts the host for eachreceived packet, minimizing latency. When traffic isheavy, the NIC issues one host interrupt for multiple,back-to-back incoming packets, preserving hostCPU cycles.Dual DMA channels The PCI interface on the 3C985B-SX server NICcontains two independent DMA channels forsimultaneous read and write operations.ASIC with on-chip MACand RISC processorThe core control for the 3C985B-SX server NICresides in a tightly integrated, high-performanceASIC. Embedded RISC processors in the ASIC providethe flexibility to add new features to the NIC andadapt it to future changes in network requirementsthrough software downloads. This embedded RISCprocessor enables NIC drivers to exploit built-infunctions on the NIC that offload operationsfrom the host to the NIC.Universal dual-voltagesignaling3.3 V and 5 VStatus LEDs LINK and DATADiagnostic support Diagnostics programs run under DOS or Windows NT.
