Texas Instruments TNETX4090 specifications MAC interface

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TNETX4090

ThunderSWITCH II9-PORT 100-/1000-MBIT/S ETHERNETSWITCH

SPWS044E ± DECEMBER 1997 ± REVISED AUGUST 1999

MAC interface

receive control

Data received from the PHYs is interpreted and assembled into the TNETX4090 buffer memory. Interpretation involves detection and removal of the preamble, extraction of the address and frame length, extraction of the IEEE Std 802.1Q header (if present), and data handling and CRC. Also included is a jabber-detection timer to detect frames that exceed the maximum length being received on the network.

giant (long) frames

The maxlen bit within each port's PortxControl register controls the maximum received frame size on that port.

DIf maxlen = 0, the maximum received frame length Is 1535 bytes if no VLAN header is inserted, or 1531 bytes if a VLAN header is inserted. (When stored within the switch, a frame never can be longer than 1535 bytes).

DIf maxlen = 1, the maximum received frame length is 1518 bytes as specified by the IEEE Std 802.3. This is the maximum length on the wire. If a VLAN header is inserted into a 1518-byte frame within the MAC, the frame is stored as a 1522-byte frame within the switch.

All received frames that exceed the maximum size are discarded by the switch.

The long option bit in StatControl indicates how the statistics for long frames should be recorded.

short frames

All received frames shorter than 64 bytes are discarded upon reception and are not stored in memory or transmitted.

receive filtering of frames

Received frames that contain an error (e.g., CRC, alignment, jabber, etc.) are discarded before transmission and the relevant statistics counter is updated.

data transmission

The MAC takes data from the TNETX4090 internal buffer memory and passes it to the PHY. The data also is synchronized to the transmit clock rate.

A CRC block checks that the outgoing frame has not been corrupted within the switch by verifying that it still has a valid CRC as the frame is being transmitted. If a CRC error is detected, it is counted in the transmit data errors counter.

transmit control

The frame control block handles the output of data to the PHYs. Several error states are handled. If a collision is detected, the state machine jams the output. If the collision was late (after the first 64-byte buffer has been transmitted), the frame is lost. If it is an early collision, the controller backs off before retrying. While operating in full duplex, both carrier-sense (CRS) mode and collision-sensing modes are disabled (the switch does not start transmitting a new frame if collision is active in full-duplex mode).

Internally, frame data only is removed from buffer memory once it has been successfully transmitted without collision (for the half-duplex ports). Transmission recovery also is handled in this state machine. If a collision is detected, frame recovery and retransmission are initiated.

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Contents Description MII MAC MIIMAC Eeprom CPU I/F DMAPCS Duplex LED Rdram Interface Jtag Interface GGP Package Bottom View Signal-to-Ball Mapping Signal Names Sorted Alphabetically Signal Ball NameReset Sdma SAD0 Terminal Functions Jtag interfaceControl logic interface Terminal Internal Description Name RESISTOR²100-/1000-Mbit/s MAC interface Gmii mode M08TXD7 M08TXD6 M08TXD5Terminal Internal Description Name Resistor Port to not support pause frames 10-/100-Mbit/s MAC interface MII mode ports 0±7 PulldownM00RENEG M01RENEG ThunderSWITCH II 9-PORT 100-/1000-MBIT/S ETHERNET Switch M04TCLK M05TCLK M06TCLK M07TCLK AD4MII management interface Rdram interface DIO interface Eeprom interface100-/1000-Mbit/s port PCS LED interface Power supplyLED interface Byte DIO Address DIO interface descriptionDIO Internal Register Address Map ThunderSWITCH II 9-PORT 100-/1000-MBIT/S ETHERNET TNETX4090VLAN1QID VLAN0QID VLAN37QID VLAN36QID TNETX4090 PCS8Status PCS8Control 0x0700 DIO interface description Port no Head Statistic Even ODD Ports Port StatisticsTail Port no Head Statistic Tail 0x90ExDMA Interface Signals Signal DescriptionAddress-Lookup Statistics Receiving/transmitting management framesState of DIO signal terminals during hardware reset DIO Interface During Hardware ResetDIO Interface State During Hardware Reset Ieee Std 802.1Q Vlan tags on the NM port Vlan ID FCS Tpid TCI CRCTNETX4090 PHY management interface Full-duplex NM portNM bandwidth and priority Interrupt processingMAC interface Adaptive performance optimization APO Interframe gap enforcementBackoff Receive versus transmit priority10-/100-Mbit/s MII ports 0±7 Speed, duplex, and flow-control negotiation100-Mbit/s Port Negotiation With the TNETE2104 100-/1000-Mbit/s PHY interface port Port 8 Duplex Negotiation in MII Mode Port 8 Pause Negotiation in MII ModeFull-duplex hardware flow control OutcomeM08GTCLK M08TXEN Pretagging and extended port awarenessPretag on transmission Transmit Pretag Bit Definitions Pretag on receptionLearning Format Receive Pretag Bit Definitions BIT Name FunctionDirected Format Receive Pretag Bit Definitions Ring-cascade topologyRXD Flow COL TXD TNETX4090 RXD Flow COL TXDM08GTCLK M08TXEN M08RXDV Switch TerminalRing-Topology Connectivity GND SCL SDAEdio TNETX4090 Eclk Summary of Eeprom load outcomes Outcome Stop Load Initd ² Fault LED EclkInteraction of Eeprom load with the SIO register Compatibility with future device revisions Port LED StatesCollision LED States State DisplayPCS duplex LED LED Status Bit Definitions and Shift OrderLamp test Multi-LED displayBUS Enable GND BUS Ctrl Rdram SIN BUS Enable GND Rdram BUS Ctrl SINTNETX4090 VCC NC Txclk Vref Rxclk VDD Sout SCHAIN0 Txclk Vref Rxclk VDDJtag Instruction Opcodes Highz instructionRacbist instruction Jtag Bist StatusIale Frame routingVlan support Address maintenance Ieee Std 802.1Q tags ± receptionIeee Std 802.1Q header ± transmission Spanning-tree supportAging algorithms Frame-Routing Algorithm SPWS044E ± December 1997 ± Revised August Port routing code Port trunking/load sharing Removal of source portPort trunking example Trunk Group 0 Port Membership Trunk0Ports RegisterTrunk Group 1 Port Membership Trunk1Ports Register Extended port awarenessFlow control Other flow-control mechanisms Hardware flow controlMulticast limit System test capabilitiesReading Rdram Internal wrap testDuplex wrap test PHY TNETX4090Recommended operating conditions MIN NOM MAX UnitTiming requirements over recommended operating conditions Jtag interface Control signalsReset see Figure Physical medium attachment interface port Receive PMA receive see FigureTransmit PMA transmit see FigureGmii transmit see Figure Gmii portGmii receive see Figure PMA and Gmii clock see Figure Gmii ClockMII ports 0±8 MII receive see FigureMII transmit see Figure MII clock see FigureRdram interface Rdram see FigureDtxclk Drxclk Dbusctrl DbusenSCS Srnw SAD1±SAD0 Sdma SDATA7± SDATA0 Srdy Sint DIO interfaceDIO and DMA writes see Figure DIO and DMA reads see Figure SCS Srnw SAD1±SAD0 Sdma SDATA7± SDATA0 SrdyEeprom reads see Figure Eeprom interfaceEeprom writes see Figure Ledclk Leddata LED interfaceLED see Figure VOH VOLTTL Output Macro Propagation-Delay-Time Voltage Waveforms VOL VDD VDD VOH50% Lvcmos Mechanical Data TNETX4090GGP Obsolete BGA TBDImportant Notice
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