Texas Instruments TMS320DM36X manual Active PHY Monitoring, PHY Register User Access

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2.8.1.3Active PHY Monitoring

Once a PHY candidate has been selected for use, the MDIO module transparently monitors its link state by reading the MDIO PHY link status register (LINK). Link change events are stored on the MDIO device and can optionally interrupt the CPU. This allows the system to poll the link status of the PHY device without continuously performing costly MDIO accesses.

2.8.1.4PHY Register User Access

When the CPU must access MDIO for configuration and negotiation, the PHY access module performs the actual MDIO read or write operation independent of the CPU. This allows the CPU to poll for completion or receive an interrupt when the read or write operation has been performed. The user access registers USERACCESSn allows the software to submit the access requests for the PHY connected to the device.

2.8.2MDIO Module Operational Overview

The MDIO module implements the 802.3 serial management interface to interrogate and control an Ethernet PHY, using a shared two-wired bus. It separately performs autodetection and records the current link status of up to 32 PHYs, polling all 32 MDIO addresses.

Application software uses the MDIO module to configure the autonegotiation parameters of the PHY attached to the EMAC, retrieve the negotiation results, and configure required parameters in the EMAC.

In this device, the Ethernet PHY attached to the system can be directly controlled and queried. The Media Independent Interface (MII) address of this PHY device is specified in one of the PHYADRMON bits in the MDIO user PHY select register (USERPHYSELn). The MDIO module can be programmed to trigger a CPU interrupt on a PHY link change event, by setting the LINKINTENB bit in USERPHYSELn. Reads and writes to registers in this PHY device are performed using the MDIO user access register (USERACCESSn).

The MDIO module powers-up in an idle state until specifically enabled by setting the ENABLE bit in the MDIO control register (CONTROL). At this time, the MDIO clock divider and preamble mode selection are also configured. The MDIO preamble is enabled by default, but can be disabled when the connected PHY does not require it. Once the MDIO module is enabled, the MDIO interface state machine continuously polls the PHY link status (by reading the generic status register) of all possible 32 PHY addresses and records the results in the MDIO PHY alive status register (ALIVE) and MDIO PHY link status register (LINK). The corresponding bit for the connected PHY (0-31) is set in ALIVE, if the PHY responded to the read request. The corresponding bit is set in LINK, if the PHY responded and also is currently linked. In addition, any PHY register read transactions initiated by the application software using USERACCESSn causes ALIVE to be updated.

The USERPHYSELn is used to track the link status of the connected PHY address. A change in the link status of the PHY being monitored sets the appropriate bit in the MDIO link status change interrupt registers (LINKINTRAW and LINKINTMASKED), if enabled by the LINKINTENB bit in USERPHYSELn.

While the MDIO module is enabled, the host issues a read or write transaction over the MII management interface using the DATA, PHYADR, REGADR, and WRITE bits in USERACCESSn. When the application sets the GO bit in USERACCESSn, the MDIO module begins the transaction without any further intervention from the CPU. Upon completion, the MDIO module clears the GO bit and sets the corresponding USERINTRAW bit (0 or 1) in the MDIO user command complete interrupt register (USERINTRAW) corresponding to USERACCESSn used. The corresponding USERINTMASKED bit (0 or

1)in the MDIO user command complete interrupt register (USERINTMASKED) may also be set,

depending on the mask setting configured in the MDIO user command complete interrupt mask set register (USERINTMASKSET) and the MDIO user interrupt mask clear register (USERINTMASKCLEAR).

A round-robin arbitration scheme is used to schedule transactions that may be queued using both USERACCESS0 and USERACCESS1. The application software must check the status of the GO bit in USERACCESSn before initiating a new transaction, to ensure that the previous transaction has completed. The application software can use the ACK bit in USERACCESSn to determine the status of a read transaction.

34 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 DiagramClock Control Industry Standards Compliance StatementMII Clocking Memory Map Signal DescriptionsMedia Independent Interface MII Connections Signal Type Description Emac and Mdio Signals for MII InterfacePin Multiplexing 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 CPUTransmit Pulse Interrupt Interrupt ControlReceive Pulse Interrupt Miscellaneous Pulse Interrupt Receive Threshold Pulse InterruptInterrupt Pacing Mdio Clock Generator Mdio ModuleMdio Module Components Global PHY Detection and Link State MonitoringActive PHY Monitoring PHY Register User AccessMdio Module Operational Overview Writing Data To a PHY Register Initializing the Mdio ModuleReading Data From 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 SupportPacket Receive Operation Receive DMA Host ConfigurationReceive Channel Enabling Receive Address Matching Hardware Receive QOS SupportReceive Channel Teardown Host Free Buffer TrackingReceive Frame Classification Receive Frame Treatment Summary Promiscuous Receive ModeReceive Frame Treatment Middle of Frame Overrun Treatment Receive OverrunMiddle of Frame Overrun Treatment Receive and Transmit Latency Transmit DMA Host ConfigurationPacket Transmit Operation Transmit Channel TeardownSoftware Reset Considerations Reset ConsiderationsTransfer Node Priority 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 FreeIntpaceen Emac Control Module Interrupt Control Register CmintctrlIntprescale Rxthreshen RxpulseenTxpulseen Bit Field Statpendinten Hostpendinten Linkinten UserintenStatpendinten Rxthreshinttstat RxpulseinttstatTxpulseinttstat 31-8 Reserved TXPULSEINTTSTATnStatpendintstat Hostpendintstat Linkintstat Userintstat StatpendintstatRximax TximaxManagement Data Input/Output Mdio Registers Mdio Version Register VersionMdio Version Register Version Field Descriptions 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 Transmit Identification and Version Register TxidverTransmit Control Register Txcontrol Field Descriptions Transmit Teardown Register Txteardown Field Descriptions Transmit Teardown Register TxteardownTxtdnch 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 RxintmaskclearMAC Interrupt Status Masked Register Macintstatmasked MAC Interrupt Status Unmasked Register MacintstatrawHostpend Statpend 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 Buffer Offset Register Rxbufferoffset Receive Maximum Length Register RxmaxlenReceive Maximum Length Register Rxmaxlen Field Descriptions 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 DescriptionsTransmit Pacing Algorithm Test Register Tpacetest Back Off Test Register BofftestBack Off Test Register Bofftest Field Descriptions 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/DeletionsDSP Products ApplicationsRfid
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