Texas Instruments TNETX4090 PHY management interface, Full-duplex NM port, Interrupt processing

Page 31

TNETX4090

ThunderSWITCH II 9-PORT 100-/1000-MBIT/S ETHERNET SWITCH

SPWS044E ± DECEMBER 1997 ± REVISED AUGUST 1999

full-duplex NM port

The NM port can intermix reception and transmission as desired. It is the direction of the NMData access (i.e., read or write) that determines whether a byte is removed from the transmit queue or added to the receive queue. The DIO interface, however, is only half duplex since it cannot do a read and write at the same time.

NM bandwidth and priority

The NM port is capable of transferring a byte to or from NMData once every 80 ns, or 100 Mbit/s. This can be sustained between the DIO port and the NM ports dedicated receive or receive buffers.

However, the NM port is prioritized lower than the other ports between its receive buffers and the external memory system so that during periods of high activity, the NM port does not cause frames to be dropped on the other ports.

interrupt processing

The SRXRDY signal and the nmrx interrupt are set when the receive FIFO is completely empty. This indicates that the NM port is ready to accept a frame of any length (up to 1535 bytes).

If the host wished to download a sequence of frames, it could use the freebuffs field to determine space availability.

PHY management interface

This interface gives the user an easy way to implement a software-controlled bit serial MII PHY management interface.

MII devices that implement the management interface consisting of MDIO and MDCLK can be accessed through an internal register (see the TNETX4090 Programmer's Reference Guide, literature number SPAU003, for details on controlling this interface). A third signal, MRESET, is provided to allow hardware reset of PHYs that support it.

All three terminals have internal pullup resistors since they can be placed in a high-impedance state to allow another bus master.

The interface does not implement any timing or MII frame formatting. The timing and frame format must be ensured by the management software setting or clearing the bits within the internal registers in an appropriate manner. Refer to the IEEE Std 802.3u and the MII device data sheets for the appropriate protocol requirements.

POST OFFICE BOX 655303 •DALLAS, TEXAS 75265

31

Image 31

Contents Description DMA MIIMAC MII MAC Eeprom CPU I/FPCS Duplex LED Rdram Interface Jtag Interface GGP Package Bottom View Signal Ball Name Signal-to-Ball Mapping Signal Names Sorted AlphabeticallyReset Sdma SAD0 Terminal Internal Description Name RESISTOR² Terminal FunctionsJtag interface Control logic interfaceM08TXD7 M08TXD6 M08TXD5 100-/1000-Mbit/s MAC interface Gmii modeTerminal Internal Description Name Resistor Port to not support pause frames Pulldown 10-/100-Mbit/s MAC interface MII mode ports 0±7M00RENEG M01RENEG M04TCLK M05TCLK M06TCLK M07TCLK AD4 ThunderSWITCH II 9-PORT 100-/1000-MBIT/S ETHERNET SwitchMII management interface Rdram interface Eeprom interface DIO interfaceLED interface Power supply100-/1000-Mbit/s port PCS LED interface DIO Internal Register Address Map DIO interface descriptionByte DIO Address TNETX4090 ThunderSWITCH II 9-PORT 100-/1000-MBIT/S ETHERNETVLAN1QID VLAN0QID VLAN37QID VLAN36QID TNETX4090 PCS8Status PCS8Control 0x0700 DIO interface description Tail Port StatisticsPort no Head Statistic Even ODD Ports 0x90Ex Port no Head Statistic TailReceiving/transmitting management frames DMA Interface SignalsSignal Description Address-Lookup Statistics Ieee Std 802.1Q Vlan tags on the NM port State of DIO signal terminals during hardware reset DIO Interface During Hardware Reset DIO Interface State During Hardware ResetCRC Vlan IDFCS Tpid TCITNETX4090 Interrupt processing PHY management interfaceFull-duplex NM port NM bandwidth and priorityMAC interface Receive versus transmit priority Adaptive performance optimization APOInterframe gap enforcement BackoffSpeed, duplex, and flow-control negotiation 10-/100-Mbit/s MII ports 0±7100-Mbit/s Port Negotiation With the TNETE2104 100-/1000-Mbit/s PHY interface port Outcome Port 8 Duplex Negotiation in MII ModePort 8 Pause Negotiation in MII Mode Full-duplex hardware flow controlPretag on transmission Pretagging and extended port awarenessM08GTCLK M08TXEN BIT Name Function Transmit Pretag Bit DefinitionsPretag on reception Learning Format Receive Pretag Bit DefinitionsTNETX4090 RXD Flow COL TXD Directed Format Receive Pretag Bit DefinitionsRing-cascade topology RXD Flow COL TXDRing-Topology Connectivity Switch TerminalM08GTCLK M08TXEN M08RXDV Edio TNETX4090 Eclk SCL SDAGND Interaction of Eeprom load with the SIO register Outcome Stop Load Initd ² Fault LED EclkSummary of Eeprom load outcomes State Display Compatibility with future device revisionsPort LED States Collision LED StatesMulti-LED display PCS duplex LEDLED Status Bit Definitions and Shift Order Lamp testSout SCHAIN0 Txclk Vref Rxclk VDD BUS Enable GND BUS Ctrl Rdram SINBUS Enable GND Rdram BUS Ctrl SIN TNETX4090 VCC NC Txclk Vref Rxclk VDDJtag Bist Status Jtag Instruction OpcodesHighz instruction Racbist instructionVlan support Frame routingIale Spanning-tree support Address maintenanceIeee Std 802.1Q tags ± reception Ieee Std 802.1Q header ± transmissionAging algorithms Frame-Routing Algorithm SPWS044E ± December 1997 ± Revised August Port routing code Removal of source port Port trunking/load sharingExtended port awareness Port trunking exampleTrunk Group 0 Port Membership Trunk0Ports Register Trunk Group 1 Port Membership Trunk1Ports RegisterFlow control System test capabilities Other flow-control mechanismsHardware flow control Multicast limitInternal wrap test Reading RdramPHY TNETX4090 Duplex wrap testMIN NOM MAX Unit Recommended operating conditionsReset see Figure Jtag interface Control signalsTiming requirements over recommended operating conditions PMA receive see Figure Physical medium attachment interface port ReceivePMA transmit see Figure TransmitGmii receive see Figure Gmii portGmii transmit see Figure Gmii Clock PMA and Gmii clock see FigureMII receive see Figure MII ports 0±8MII clock see Figure MII transmit see FigureDbusctrl Dbusen Rdram interfaceRdram see Figure Dtxclk DrxclkDIO and DMA writes see Figure DIO interfaceSCS Srnw SAD1±SAD0 Sdma SDATA7± SDATA0 Srdy Sint SCS Srnw SAD1±SAD0 Sdma SDATA7± SDATA0 Srdy DIO and DMA reads see FigureEeprom writes see Figure Eeprom interfaceEeprom reads see Figure LED see Figure LED interfaceLedclk Leddata VOL VOHTTL Output Macro Propagation-Delay-Time Voltage Waveforms 50% Lvcmos VDD VOHVOL VDD Mechanical Data TBD TNETX4090GGP Obsolete BGAImportant Notice