Texas Instruments TNETX3270 Interface description, Receiving/transmitting management frames

Page 18

TNETX3270

ThunderSWITCH24/3 ETHERNETSWITCH

WITH 24 10-MBIT/S PORTS AND 3 10-/100-MBIT/S PORTS

SPWS043B ± NOVEMBER 1997 ± REVISED APRIL 1999

interface description

DIO interface

The DIO interface is a general-purpose interface that can be used with a wide range of microprocessor or computer systems. The interface supports external DMA controllers.

This interface can be used to configure the TNETX3270 using an optional attached CPU (or EEPROM), and to access statistics registers. In addition, this allows access to an internal network management (NM) port that can be transferred between the CPU and the TNETX3270 to support spanning tree, SNMP, and RMON. Either the CPU can read and write packets directly under software control or an external DMA controller can be used to improve performance.

When accessing the statistics values from the DIO port, it is necessary to perform four 1-byte DIO reads to obtain the full 32-bit counter. Counters always should be read in ascending byte-address order (0, 1, 2, 3). To prevent the counter being updated while reading the four bytes, the entire 32-bit counter value is transferred to a holding register when byte 0 is read.

receiving/transmitting management frames

Frames originating within the host are written to the NM port via the NMRxcontrol and NMdata registers. Once a frame has been fully written, it is then received by the switch and routed to the destination port(s).

Frames that were routed to this port from any of the switch ports are placed in a queue until the host is ready to read them via the NMTxcontrol and NMdata registers. They then are effectively transmitted out of the switch.

SDMA can be used to transmit or receive management frames (the SAD1±SAD0 pins are ignored when SDMA is asserted) (see Table 3). When SDMA is asserted, the switch uses the value in the DMAaddress register instead of the DIO address registers to access frame data (this also can be used to access the switch statistics). STXRDY and SRXRDY, the interrupts, freebuffs, eof, sof, and iof mechanisms can be used, as desired, to prevent unwanted stalls on the DIO bus during busy periods.

 

 

 

Table 3. DMA Interface Signals

 

 

 

 

 

SIGNAL

DESCRIPTION

 

 

 

 

 

Automatically sets up DIO address using the DMAaddress register

 

SDMA

 

 

 

STXRDY

Indicates that at least one data frame buffer can be read by the management CPU

 

 

SRXRDY

Indicates that the management CPU can write a frame of any size up to 1535 bytes

 

 

 

 

state of DIO signals during hardware reset

The CPU can perform a hardware reset by writing to an address in the range 0x4000±0x5FFF (writes to a DMA address in this range have no effect on reset). This is equivalent to asserting the hardware RESET pin. During hardware reset, the output and bidirectional DIO pins behave as shown in Table 4.

Table 4. DIO Interface During Hardware Reset

 

DIO INTERFACE

STATE DURING HARDWARE RESET

 

SIGNAL

 

 

 

 

 

 

 

SDATA7±SDATA0

High impedance. Resistively pulled up.

 

 

 

 

 

 

High impedance. Resistively pulled up.

 

SRDY

 

 

 

 

 

SRXRDY

Driven high

 

 

 

 

STXRDY

Driven low

 

 

 

 

18

POST OFFICE BOX 655303 •DALLAS, TEXAS 75265

Page 17 Page 19
Image 18
Page 17 Page 19
Contents TNETX3270 ThunderSWITCH 24/3 ETHERNET Switch With 24 10-MBIT/S Ports and 3 10-/100-MBIT/S PortsWith 24 10-MBIT/S Ports and 3 10-/100-MBIT/S Ports DescriptionThunderSWITCH 24/3 ETHERNET ContentsPGV Package TOP View ThunderSWITCH  24/3Terminal Internal Description Name RESISTOR³ 10-/100-Mbit/s MAC interface ports 24±26³ Terminal Internal Description Name ResistorTerminal Functions 10-/100-Mbit/s MAC interface ports 24±26 ²Dclk Sdram interfaceDras Dcas DrasHost DIO interface Serial MII management PHY interface Eeprom interfaceJtag interface Power interface Summary of signal terminals by signal group functionMiscellaneous DIO register groups Internal Register and Statistics Memory MapVlan Detailed DIO Register Map Byte DIO AddressSIO VLAN5QID VLAN4QID VLAN1QID VLAN0QIDVLAN3QID VLAN2QID VLAN7QID VLAN6QIDVLAN21QID VLAN20QID VLAN17QID VLAN16QIDVLAN19QID VLAN18QID VLAN23QID VLAN22QIDFindnode23±16 Findnode31±24 Findnode39±32 Findnode47±40 IntenableTNETX3270 reset reinitializes the TNETX3270 0x40000x5FFF Findcontrol Findnode7±0 Findnode15±8State of DIO signals during hardware reset Interface descriptionReceiving/transmitting management frames Network management port Frame format on the NM port Tpid TCI Vlan IDFCS CRCGiant long frames MII serial management interface PHY managementMbit/s and 10-/100-Mbit/s MAC interface receive control Short framesTransmit control Receive filtering of framesData transmission Adaptive performance optimization APO transmit pacingReceive versus transmit priority Uplink pretaggingSource-Port Pretag Encoding Source PortReceived Pretag Port Assignments TAGPort 27 NM Eeprom interface Edio TNETX3270 Eclk SCL SDAGND Summary of Eeprom load outcomes Outcome Stop Load Initd ² Fault LED EclkInteraction of Eeprom load with the SIO register Summary of Eeprom Load OutcomesHighz instruction Jtag interfaceJtag Instruction Opcodes LED interfaceLamp test Hardware configurationsLED Status Bit Definitions and Shift Order Multi-LED displayMbit/s Interface Connections TNETX3270 TNETE2008 TerminalM06TXD Port CLK Sync TXD3M03TXD M04TXD M03COLConnecting to TNETE2008 PHY² 10-/100-Mbit/s MAC interfaces ports 24±26 10-/100-Mbit/s port configurationSwitch TNETE2101 Terminal 100-Mbit/s Interface ConnectionsSpeed Configuration ± MxxFORCE10 Duplex Configuration ± MxxFORCEHD10-/100-Mbit/s port configuration in a nonmanaged switch 10-/100-Mbit/s port configuration in a managed switch Terminals Sdram Terminal Function TNETX3270 Sdram interface TNETX3270 Terminal Interface to SDRAMsSdram Terminals Not Driven by the TNETX3270 Held Sdram Terminal Terminal FunctionInitialization TNETX3270 State Terminal During ResetSDRAM-type and quantity indication RefreshFrame routing Vlan supportIale Address maintenance Ieee Std 802.1Q headers ± receptionIeee Std 802.1Q headers ± transmission Spanning-tree support Aging algorithmsFrame-routing determination Frame-Routing Algorithm SPWS043B ± November 1997 ± Revised April Port mirroring CDEPort trunking/load sharing Flow controlCollision-based flow control Ieee Std 802.3 flow controlPause frame reception Internal wrap test Duplex wrap test PHY TNETX3270Copy to uplink Recommended operating conditions MIN NOM MAX UnitParameter Test Conditions MIN TYP MAX Unit Test measurement MIN MAX Unit Parameter MIN MAX Unit10-/100-Mbit/s MAC interface Timing requirements see Note 7 and Figure10-/100-Mbit/sreceive ports 24, 25 Timing requirements see Figure 10-/100-Mbit/stransmit ports 24, 25,Sdram command to command see Figure Dclk TdDA Delay time, from Dclk ↑ to DA InvalidSdram subcycle Dras DcasDIO/DMA interface DIO/DMA write cycleSDATA7± Z SDATA0 DIO/DMA read cycle Serial MII Management Read/Write Cycle Eeprom Parameter TNETX3150 TNETX3150A Unit MIN MAXTdLEDDATA Delay time, from LEDCLK↑ to 1st LED invalid ² During hard reset, Ledclk runs continuouslyThRESET Hold time Low after Oscin ↑ Power-up Oscin and Reset Timing requirements see FigureTsuRESET Setup time Low before Oscin ↑ TtOSCIN Transition time, Oscin rise and fallMechanical Data Important Notice
Top Page Image Contents