Texas Instruments TMS320DM36X manual Transfer Node Priority, Reset Considerations

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Receive overrun is prevented if the receive memory cell latency is less than the time required to transmit a 64-byte cell on the wire (0.512 ms in 1 Gbps mode, 5.12 ms in 100 Mbps mode, or 51.2ms in 10 Mbps mode). The latency time includes any required buffer descriptor reads for the cell data.

Latency to descriptor RAM is low because RAM is local to the EMAC, as it is part of the EMAC control module.

2.14 Transfer Node Priority

The DM36x device contains a chip-level register, master priority register (MSTPRI), that is used to set the priority of the transfer node used in issuing memory transfer requests to system memory.

Although the EMAC has internal FIFOs to help alleviate memory transfer arbitration problems, the average transfer rate of data read and written by the EMAC to internal or external processor memory must be at least that of the Ethernet wire rate. In addition, the internal FIFO system can not withstand a single memory latency event greater than the time it takes to fill or empty a TXCELLTHRESH number of internal 64-byte FIFO cells.

For 100 Mbps operation, these restrictions translate into the following rules:

•The short-term average, each 64-byte memory read/write request from the EMAC must be serviced in no more than 5.12 μs.

•Any single latency event in request servicing can be no longer than (5.12 × TXCELLTHRESH) μs.

Bits 0-2 of the second chip-level master priority register (MSTPRI1) are used to set the transfer node priority within the Switched Central Resource (SCR5) for the EMAC master peripheral.

A value of 000b has the highest priority, while 111b has the lowest priority. The default priority assigned to the EMAC is 100b. It is important to have a balance between all peripherals. In most cases, the default priorities will not need adjustment. For more information on the master peripherals priorities, see the device-specific data manual.

2.15 Reset Considerations

2.15.1Software Reset Considerations

Peripheral clock and reset control is done through the Power and Sleep Controller (PSC) module included with the device. For more on how the EMAC, MDIO, and EMAC control module are disabled or placed in reset at runtime from the registers located in the PSC module, see Section 2.18.

NOTE: For proper operation, both the EMAC and EMAC control module must be reset in the following sequence. First, the soft reset of the EMAC module should be commanded. After the reset takes effect (verified by reading back SOFTRESET), the soft reset of the EMAC control module should be commanded.

Within the peripheral there are two controls to separately reset the EMAC and the EMAC control module.

•The EMAC component of the Ethernet MAC peripheral can be placed in a reset state by writing to the soft reset register (SOFTRESET). Writing a 1 to the SOFTRESET bit, causes the EMAC logic to be reset and the register values to be set to their default values. Software reset occurs when the receive and transmit DMA controllers are in an idle state to avoid locking up the configuration bus; it is the responsibility of the software to verify that there are no pending frames to be transferred. After writing a 1 to the SOFTRESET bit, it may be polled to determine if the reset has occurred. If a 1 is read, the reset has not yet occurred; if a 0 is read, then a reset has occurred.

•The EMAC control module software reset register (CMSOFTRESET) is used to place the EMAC control module logic in soft reset. This resets the control logic, the EMAC registers, as well as, the EMAC control module 8KB internal memory that may be used for storing the transfer descriptors.

After a software reset operation, all the EMAC registers need to be reinitialized for proper data transmission.

Unlike the EMAC module, the MDIO and EMAC control modules cannot be placed in reset from a register inside their memory map.

50 Ethernet Media Access Controller (EMAC)/Management Data Input/Output SPRUFI5B –March 2009 –Revised December 2010

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Contents Users Guide Submit Documentation Feedback Mdio Registers Mdio Version Register Version Mdio Control Register Control Appendix a Appendix BList of Figures Transmit Interrupt Mask Set Register Txintmaskset List of Tables MAC Control Register Maccontrol Field Descriptions Read This First Related Documentation From Texas Instruments Related Documentation From Texas Instruments Features Purpose of the PeripheralFunctional Block Diagram Emac and Mdio Block DiagramMII Clocking Industry Standards Compliance StatementClock Control Media Independent Interface MII Connections Signal DescriptionsMemory Map Pin Multiplexing Emac and Mdio Signals for MII InterfaceSignal Type Description Ethernet Frame Description Ethernet Protocol OverviewEthernet Frame Format Field Bytes DescriptionPacket Buffer Descriptors Ethernet’s Multiple Access ProtocolProgramming Interface WordBasic Descriptor Description Field Field DescriptionTransmit and Receive Descriptor Queues Transmit and Receive Emac Interrupts Transmit Buffer Descriptor Format Example 1. Transmit Buffer Descriptor in C Structure FormatBuffer Offset Next Descriptor PointerBuffer Pointer Buffer LengthEnd of Queue EOQ Flag End of Packet EOP FlagOwnership Owner Flag Teardown Complete Tdowncmplt FlagReceive Buffer Descriptor Format Receive Buffer Descriptor FormatExample 2. Receive Buffer Descriptor in C Structure Format Buffer Length CRC Error Crcerror Flag Code Error Codeerror FlagAlignment Error Alignerror Flag Jabber FlagBus Arbiter Emac Control ModuleInternal Memory CPUReceive Pulse Interrupt Interrupt ControlTransmit Pulse Interrupt Interrupt Pacing Receive Threshold Pulse InterruptMiscellaneous Pulse Interrupt Mdio Clock Generator Mdio ModuleMdio Module Components Global PHY Detection and Link State MonitoringMdio Module Operational Overview PHY Register User AccessActive PHY Monitoring Reading Data From a PHY Register Initializing the Mdio ModuleWriting Data To a PHY Register Example of Mdio Register Access Code Example 3. Mdio Register Access MacrosReceive DMA Engine Emac ModuleEmac Module Components Receive FifoReceive Address Clock and Reset LogicMAC Receiver Transmit DMA EngineEmac Module Operational Overview Receive Control Media Independent Interface MIIData Reception Receive Inter-Frame IntervalCollision-Based Receive Buffer Flow Control Ieee 802.3x-Based Receive Buffer Flow ControlAdaptive Performance Optimization APO Transmit ControlCRC Insertion Interpacket-Gap IPG EnforcementTransmit Flow Control Speed, Duplex, and Pause Frame SupportReceive Channel Enabling Receive DMA Host ConfigurationPacket Receive Operation Receive Address Matching Hardware Receive QOS SupportReceive Frame Classification Host Free Buffer TrackingReceive Channel Teardown Receive Frame Treatment Promiscuous Receive ModeReceive Frame Treatment Summary Middle of Frame Overrun Treatment Receive OverrunMiddle of Frame Overrun Treatment Receive and Transmit Latency Transmit DMA Host ConfigurationPacket Transmit Operation Transmit Channel TeardownTransfer Node Priority Reset ConsiderationsSoftware Reset Considerations Enabling the EMAC/MDIO Peripheral Hardware Reset ConsiderationsInitialization Emac Control Module InitializationExample 4. Emac Control Module Initialization Code Mdio Module Initialization Example 5. Mdio Module Initialization CodeEmac Module Initialization Receive Threshold Interrupts Interrupt SupportEmac Module Interrupt Events and Requests Transmit Packet Completion InterruptsReceive Packet Completion Interrupts Host Error Interrupt Statistics InterruptLink Change Interrupt User Access Completion InterruptMdio Module Interrupt Events and Requests Proper Interrupt ProcessingEmulation Control Power ManagementEmulation Considerations Soft Free DescriptionAcronym Register Description Emac Control Module RegistersSlave Vbus Bit Field Value DescriptionEmac Control Module Emulation Control Register Cmemcontrol Emac Control Module Software Reset Register CmsoftresetSoftreset Soft FreeIntprescale Emac Control Module Interrupt Control Register CmintctrlIntpaceen Rxthreshen RxpulseenTxpulseen Statpendinten Statpendinten Hostpendinten Linkinten UserintenBit Field Rxthreshinttstat RxpulseinttstatTxpulseinttstat 31-8 Reserved TXPULSEINTTSTATnStatpendintstat Hostpendintstat Linkintstat Userintstat StatpendintstatRximax TximaxMdio Version Register Version Field Descriptions Mdio Version Register VersionManagement Data Input/Output Mdio Registers Mdio Control Register Control Mdio Control Register Control Field DescriptionsPHY Acknowledge Status Register Alive Field Descriptions PHY Acknowledge Status Register AlivePHY Link Status Register Link PHY Link Status Register Link Field Descriptions31-2 Reserved Will clear the event and writing a 0 has no effect No Mdio user command complete event USERINTMASKED0 and USERINTMASKED1 correspond to USERACCESS0 W1S-0 Mdio User Command Complete Interrupt Mask Clear Register Mdio User Command Complete Interrupt Mask Clear RegisterMdio User Access Register 0 USERACCESS0 Mdio User Access Register 0 USERACCESS0 Field DescriptionsPhyadrmon Mdio User PHY Select Register 0 USERPHYSEL0Linksel Linkintenb LinkselMdio User Access Register 1 USERACCESS1 Mdio User Access Register 1 USERACCESS1 Field DescriptionsMdio User PHY Select Register 1 USERPHYSEL1 Mdio User PHY Select Register 1 USERPHYSEL1Ethernet Media Access Controller Emac Registers Offset Acronym Register Description Network Statistics Registers Transmit Control Register Txcontrol Field Descriptions Transmit Identification and Version Register TxidverTransmit Control Register Txcontrol Txtdnch Transmit Teardown Register TxteardownTransmit Teardown Register Txteardown Field Descriptions Rxmajorver Rxminorver Receive Identification and Version Register RxidverRxident RxmajorverReceive Control Register Rxcontrol Field Descriptions Receive Control Register RxcontrolReceive Teardown Register Rxteardown Receive Teardown Register Rxteardown Field DescriptionsTransmit Interrupt Status Unmasked Register Txintstatraw TX7PENDTransmit Interrupt Status Masked Register Txintstatmasked Transmit Interrupt Status Masked Register TxintstatmaskedTransmit Interrupt Mask Set Register Txintmaskset TX7MASKTransmit Interrupt Mask Clear Register Txintmaskclear Transmit Interrupt Mask Clear Register TxintmaskclearMAC Input Vector Register Macinvector Field Descriptions MAC Input Vector Register MacinvectorMAC End Of Interrupt Vector Register Maceoivector StatpendReceive Interrupt Status Unmasked Register Rxintstatraw RX7PENDReceive Interrupt Status Masked Register Rxintstatmasked Receive Interrupt Status Masked Register RxintstatmaskedReceive Interrupt Mask Set Register Rxintmaskset RX7MASKReceive Interrupt Mask Clear Register Rxintmaskclear Receive Interrupt Mask Clear Register RxintmaskclearHostpend Statpend MAC Interrupt Status Unmasked Register MacintstatrawMAC Interrupt Status Masked Register Macintstatmasked Hostmask Statmask MAC Interrupt Mask Set Register MacintmasksetMAC Interrupt Mask Clear Register Macintmaskclear HostmaskRxcsfen Rxcefen Rxcafen Rxpasscrc Rxqosen RxnochainRxcmfen RxpromchFrames containing errors are filtered Receive multicast channel select Receive Unicast Enable Set Register Rxunicastset RXCH7ENReceive Unicast Clear Register Rxunicastclear Receive Unicast Clear Register RxunicastclearReceive Maximum Length Register Rxmaxlen Field Descriptions Receive Maximum Length Register RxmaxlenReceive Buffer Offset Register Rxbufferoffset Rxfilterthresh Receive Channel 0-7 Free Buffer Count Register RXnFREEBUFFER MAC Control Register Maccontrol MAC Control Register Maccontrol Field DescriptionsLoopback TxflowenRxbufferflowen FullduplexMAC Status Register Macstatus MAC Status Register Macstatus Field DescriptionsRxqosact Emulation Control Register Emcontrol Field Descriptions Emulation Control Register EmcontrolFifo Control Register Fifocontrol Fifo Control Register Fifocontrol Field DescriptionsMAC Configuration Register Macconfig Field Descriptions MAC Configuration Register MacconfigSoft Reset Register Softreset Soft Reset Register Softreset Field DescriptionsMAC Source Address Low Bytes Register Macsrcaddrlo MAC Source Address High Bytes Register MacsrcaddrhiMAC Hash Address Register 1 MACHASH1 Field Descriptions MAC Hash Address Register 1 MACHASH1MAC Hash Address Register 2 MACHASH2 MAC Hash Address Register 2 MACHASH2 Field DescriptionsBack Off Test Register Bofftest Field Descriptions Back Off Test Register BofftestTransmit Pacing Algorithm Test Register Tpacetest Receive Pause Timer Register Rxpause Field Descriptions Receive Pause Timer Register RxpauseTransmit Pause Timer Register Txpause Transmit Pause Timer Register Txpause Field DescriptionsValid Matchfilt Channel MACADDR0 MACADDR1 MAC Address Low Bytes Register MacaddrloMAC Address Low Bytes Register Macaddrlo Field Descriptions ValidMAC Index Register Macindex Field Descriptions MAC Address High Bytes Register MacaddrhiMAC Index Register Macindex MACADDR2 MACADDR3 MACADDR4 MACADDR5TXnHDP Transmit Channel 0-7 Completion Pointer Register TXnCP Receive Channel 0-7 Completion Pointer Register RXnCPBroadcast Receive Frames Register Rxbcastframes Network Statistics RegistersGood Receive Frames Register Rxgoodframes Multicast Receive Frames Register RxmcastframesPause Receive Frames Register Rxpauseframes Receive CRC Errors Register RxcrcerrorsReceive Alignment/Code Errors Register Rxaligncodeerrors Receive Oversized Frames Register RxoversizedReceive Frame Fragments Register Rxfragments Receive Jabber Frames Register RxjabberReceive Undersized Frames Register Rxundersized Filtered Receive Frames Register RxfilteredGood Transmit Frames Register Txgoodframes Receive QOS Filtered Frames Register RxqosfilteredReceive Octet Frames Register Rxoctets Broadcast Transmit Frames Register TxbcastframesTransmit Collision Frames Register Txcollision Pause Transmit Frames Register TxpauseframesDeferred Transmit Frames Register Txdeferred Transmit Single Collision Frames Register TxsinglecollTransmit Late Collision Frames Register Txlatecoll Transmit Underrun Error Register TxunderrunTransmit Carrier Sense Errors Register Txcarriersense Transmit Octet Frames Register TxoctetsSubmit Documentation Feedback Network Octet Frames Register Netoctets Receive DMA Overruns Register RxdmaoverrunsAppendix a Glossary Physical Layer Definitions Term DefinitionDocument Revision History Reference Additions/Modifications/DeletionsRfid Products ApplicationsDSP
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