Am79C976

The Am79C976 controller is a highly-integrated 32-bit full-duplex, 10/100-Megabit per second (Mbps) Ethernet controller solution, designed to address highperformance 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.

The Am79C976 controller also has several enhancements over its predecessor, the Am79C971 PCnet-FAST device. In addition to providing access to a larger SSRAM, it further reduces system implementation cost by the addition of a new EEPROM programmable pin (PHY_RST) and the integration of the PAL function needed for Magic Packet application. The PHY_RST pin is implemented to reset the external PHY without increasing the load to the PCI bus and to block RST to the PHY when PG input is LOW.

The 32-bit multiplexed bus interface unit provides a direct interface to the PCI local bus, simplifying the design of an Ethernet node in a PC system. The Am79C976 controller provides the complete interface to an Expansion ROM or Flash device allowing add-on card designs with only a single load per PCI bus interface pin. With its built-in support for both little and big endian byte alignment, this controller also addresses non-PC applications. The Am79C976 controller's advanced CMOS design allows the bus interface to be connected to either a +5-V or a +3.3-V signaling environment. An IEEE 1149.1-compliant JTAG test interface for board-level testing is also provided.

The Am79C976 controller is also compliant with the PC97, PC98, PC99, and Network PC (Net PC) specifications. It includes the full implementation of the Microsoft OnNow and ACPI specifications, which are backward compatible with the Magic Packet technology, and it is compliant with the PCI Bus Power Management Interface Specification by supporting the four power management states (D0, D1, D2, and D3), the optional PME pin, and the necessary configuration and data registers.

The Am79C976 controller is ideally suited for Net PC,motherboard, network interface card (NIC), and embedded designs. It is available in a 208-pin Plastic Quad Flat Pack (PQFP) package.

The Am79C976 controller contains a bus interface unit, a DMA Buffer Management Unit, an ISO/IEC 8802-3 (IEEE 802.3)-compliant Media Access Controller (MAC), and an IEEE 802.3-compliant MII. An interface to an external RAM of up to 4 Mbytes is provided for frame storage. The MII supports IEEE 802.3-compliant full-duplex and half-duplex operations at 10 Mbps or 100 Mbps. The MII TX and RX clock signals can be stopped independently for home networking applications.

The Am79C976 controller is register compatible with the LANCE™ (Am7990) and C-LANCE™ (Am79C90) Ethernet controllers, and all Ethernet controllers in the PCnet Family except ILACC™ (Am79C900), including the PCnet™-ISA controller (Am79C960), PCnet™-ISA+ (Am79C961), PCnet™-ISA II (Am79C961A), PCnet™-32 (Am79C965), PCnet™- PCI (Am79C970), PCnet™-PCI II (Am79C970A), and the PCnet™-FAST (Am79C971).

The Buffer Management Unit supports the LANCE and PCnet descriptor software models.

The Am79C976 controller supports auto-configuration in the PCI configuration space. Additional Am79C976 controller configuration parameters, including the unique IEEE physical address, can be read from an external nonvolatile memory (EEPROM) immediately following system reset.

In addition, the device provides programmable on-chip LED drivers for transmit, receive, collision, link integrity, Magic Packet status, activity, address match, fullduplex, or 100 Mbps status. The Am79C976 controller also provides an EADI to allow external hardware address filtering in internetworking applications and a receive frame tagging feature.

With the rise of embedded networking applications operating in harsh environments where temperatures may exceed the normal commercial temperature (0^oC to +70^oC) window, an industrial temperature (-40^oC to +85^oC) version is available. This industrial temperature version of the PCnet-PRO Ethernet controller is characterized  across the industrial temperature range (-40^oC to +85
^oC) within the published power supply specification (4.75V to 5.25V; ±5% Vcc). Thus, conformance of the PCnet-PRO performance over this temperature range is guaranteed by  a design and characterization monitor.