Clock Control, MII Clocking | Texas Instruments TMS320DM36X manual

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Architecture

The EMAC and MDIO interrupts are combined within the control module, so only the control module interrupt needs to be monitored by the application software or device driver. The EMAC control module combines the EMAC and MDIO interrupts and generates 4 separate interrupts to the ARM through the ARM interrupt controller. See Section 2.17.4 for details of interrupt multiplex logic of the EMAC control module.

1.4Industry Standard(s) Compliance Statement

The EMAC peripheral conforms to the IEEE 802.3 standard, describing the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) Access Method and Physical Layer specifications. The IEEE 802.3 standard has also been adopted by ISO/IEC and re-designated as ISO/IEC 8802-3:2000(E).

In difference from this standard, the EMAC peripheral does not use the Transmit Coding Error signal MTXER. Instead of driving the error pin when an underflow condition occurs on a transmitted frame, the EMAC intentionally generates an incorrect checksum by inverting the frame CRC, so that the transmitted frame is detected as an error by the network.

2Architecture

This section discusses the architecture and basic function of the EMAC/MDIO module.

2.1Clock Control

The frequencies for the transmit and receive clocks are fixed by the IEEE 802.3 specification as:

•2.5 MHz at 10 Mbps

•25 MHz at 100 Mbps

All EMAC logic is clocked synchronously with the PLL peripheral clock. The MDIO clock can be controlled through the application software, by programming the divide-down factor in the MDIO control register (CONTROL).

2.1.1MII Clocking

The transmit and receive clock sources are provided from an external PHY via the EMAC_TX_CLK and EMAC_RX_CLK pins. These clocks are inputs to the EMAC module and operate at 2.5 MHz in 10 Mbps mode and at 25 MHz in 100 Mbps mode. For timing purposes, data is transmitted and received with reference to EMAC_TX_CLK and EMAC_RX_CLK, respectively.

SPRUFI5B –March 2009 –Revised December 2010 Ethernet Media Access Controller (EMAC)/Management Data Input/Output 15

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Texas Instruments TMS320DM36X manual Industry Standards Compliance Statement, Clock Control, MII Clocking

Contents

Users Guide Submit Documentation Feedback Mdio Registers Mdio Version Register Version Mdio Control Register Control Appendix B Appendix a List 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 Purpose of the Peripheral Features Emac and Mdio Block Diagram Functional Block Diagram Industry Standards Compliance Statement Clock ControlMII Clocking Signal Descriptions Memory MapMedia Independent Interface MII Connections Emac and Mdio Signals for MII Interface Signal Type DescriptionPin Multiplexing Field Bytes Description Ethernet Protocol OverviewEthernet Frame Format Ethernet Frame Description Word Ethernet’s Multiple Access ProtocolProgramming Interface Packet Buffer Descriptors Field Field Description Basic Descriptor Description Transmit and Receive Descriptor Queues Transmit and Receive Emac Interrupts Example 1. Transmit Buffer Descriptor in C Structure Format Transmit Buffer Descriptor Format Buffer Length Next Descriptor PointerBuffer Pointer Buffer Offset Teardown Complete Tdowncmplt Flag End of Packet EOP FlagOwnership Owner Flag End of Queue EOQ Flag Receive Buffer Descriptor Format Receive Buffer Descriptor Format Example 2. Receive Buffer Descriptor in C Structure Format Buffer Length Jabber Flag Code Error Codeerror FlagAlignment Error Alignerror Flag CRC Error Crcerror Flag CPU Emac Control ModuleInternal Memory Bus Arbiter Interrupt Control Transmit Pulse InterruptReceive Pulse Interrupt Receive Threshold Pulse Interrupt Miscellaneous Pulse InterruptInterrupt Pacing Global PHY Detection and Link State Monitoring Mdio ModuleMdio Module Components Mdio Clock Generator PHY Register User Access Active PHY MonitoringMdio Module Operational Overview Initializing the Mdio Module Writing Data To a PHY RegisterReading Data From a PHY Register Example 3. Mdio Register Access Macros Example of Mdio Register Access Code Receive Fifo Emac ModuleEmac Module Components Receive DMA Engine Transmit DMA Engine Clock and Reset LogicMAC Receiver Receive Address Emac Module Operational Overview Receive Inter-Frame Interval Media Independent Interface MIIData Reception Receive Control Ieee 802.3x-Based Receive Buffer Flow Control Collision-Based Receive Buffer Flow Control Interpacket-Gap IPG Enforcement Transmit ControlCRC Insertion Adaptive Performance Optimization APO Speed, Duplex, and Pause Frame Support Transmit Flow Control Receive DMA Host Configuration Packet Receive OperationReceive Channel Enabling Hardware Receive QOS Support Receive Address Matching Host Free Buffer Tracking Receive Channel TeardownReceive Frame Classification Promiscuous Receive Mode Receive Frame Treatment SummaryReceive Frame Treatment Receive Overrun Middle of Frame Overrun TreatmentMiddle of Frame Overrun Treatment Transmit Channel Teardown Transmit DMA Host ConfigurationPacket Transmit Operation Receive and Transmit Latency Reset Considerations Software Reset ConsiderationsTransfer Node Priority Emac Control Module Initialization Hardware Reset ConsiderationsInitialization Enabling the EMAC/MDIO Peripheral Example 4. Emac Control Module Initialization Code Example 5. Mdio Module Initialization Code Mdio Module Initialization Emac Module Initialization Transmit Packet Completion Interrupts Interrupt SupportEmac Module Interrupt Events and Requests Receive Threshold Interrupts Receive Packet Completion Interrupts Statistics Interrupt Host Error Interrupt Proper Interrupt Processing User Access Completion InterruptMdio Module Interrupt Events and Requests Link Change Interrupt Soft Free Description Power ManagementEmulation Considerations Emulation Control Bit Field Value Description Emac Control Module RegistersSlave Vbus Acronym Register Description Soft Free Emac Control Module Software Reset Register CmsoftresetSoftreset Emac Control Module Emulation Control Register Cmemcontrol Emac Control Module Interrupt Control Register Cmintctrl IntpaceenIntprescale Rxpulseen Rxthreshen Txpulseen Statpendinten Hostpendinten Linkinten Userinten Bit FieldStatpendinten Rxpulseinttstat Rxthreshinttstat 31-8 Reserved TXPULSEINTTSTATn Txpulseinttstat Statpendintstat Statpendintstat Hostpendintstat Linkintstat Userintstat Tximax Rximax Mdio Version Register Version Management Data Input/Output Mdio RegistersMdio Version Register Version Field Descriptions Mdio Control Register Control Field Descriptions Mdio Control Register Control PHY Link Status Register Link Field Descriptions PHY Acknowledge Status Register AlivePHY Link Status Register Link PHY Acknowledge Status Register Alive Field Descriptions 31-2 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 Register Mdio User Access Register 0 USERACCESS0 Field Descriptions Mdio User Access Register 0 USERACCESS0 Linksel Mdio User PHY Select Register 0 USERPHYSEL0Linksel Linkintenb Phyadrmon Mdio User Access Register 1 USERACCESS1 Field Descriptions Mdio User Access Register 1 USERACCESS1 Mdio User PHY Select Register 1 USERPHYSEL1 Mdio User PHY Select Register 1 USERPHYSEL1 Ethernet Media Access Controller Emac Registers Offset Acronym Register Description Network Statistics Registers Transmit Identification and Version Register Txidver Transmit Control Register TxcontrolTransmit Control Register Txcontrol Field Descriptions Transmit Teardown Register Txteardown Transmit Teardown Register Txteardown Field DescriptionsTxtdnch Rxmajorver Receive Identification and Version Register RxidverRxident Rxmajorver Rxminorver Receive Teardown Register Rxteardown Field Descriptions Receive Control Register RxcontrolReceive Teardown Register Rxteardown Receive Control Register Rxcontrol Field Descriptions TX7PEND Transmit Interrupt Status Unmasked Register Txintstatraw Transmit Interrupt Status Masked Register Txintstatmasked Transmit Interrupt Status Masked Register Txintstatmasked TX7MASK Transmit Interrupt Mask Set Register Txintmaskset Transmit Interrupt Mask Clear Register Txintmaskclear Transmit Interrupt Mask Clear Register Txintmaskclear Statpend MAC Input Vector Register MacinvectorMAC End Of Interrupt Vector Register Maceoivector MAC Input Vector Register Macinvector Field Descriptions RX7PEND Receive Interrupt Status Unmasked Register Rxintstatraw Receive Interrupt Status Masked Register Rxintstatmasked Receive Interrupt Status Masked Register Rxintstatmasked RX7MASK Receive Interrupt Mask Set Register Rxintmaskset Receive Interrupt Mask Clear Register Rxintmaskclear Receive Interrupt Mask Clear Register Rxintmaskclear MAC Interrupt Status Unmasked Register Macintstatraw MAC Interrupt Status Masked Register MacintstatmaskedHostpend Statpend Hostmask MAC Interrupt Mask Set Register MacintmasksetMAC Interrupt Mask Clear Register Macintmaskclear Hostmask Statmask Rxpromch Rxpasscrc Rxqosen RxnochainRxcmfen Rxcsfen Rxcefen Rxcafen Frames containing errors are filtered Receive multicast channel select RXCH7EN Receive Unicast Enable Set Register Rxunicastset Receive Unicast Clear Register Rxunicastclear Receive Unicast Clear Register Rxunicastclear Receive Maximum Length Register Rxmaxlen Receive Buffer Offset Register RxbufferoffsetReceive Maximum Length Register Rxmaxlen Field Descriptions Rxfilterthresh Receive Channel 0-7 Free Buffer Count Register RXnFREEBUFFER MAC Control Register Maccontrol Field Descriptions MAC Control Register Maccontrol Fullduplex TxflowenRxbufferflowen Loopback MAC Status Register Macstatus Field Descriptions MAC Status Register Macstatus Rxqosact Fifo Control Register Fifocontrol Field Descriptions Emulation Control Register EmcontrolFifo Control Register Fifocontrol Emulation Control Register Emcontrol Field Descriptions Soft Reset Register Softreset Field Descriptions MAC Configuration Register MacconfigSoft Reset Register Softreset MAC Configuration Register Macconfig Field Descriptions MAC Source Address High Bytes Register Macsrcaddrhi MAC Source Address Low Bytes Register Macsrcaddrlo MAC Hash Address Register 2 MACHASH2 Field Descriptions MAC Hash Address Register 1 MACHASH1MAC Hash Address Register 2 MACHASH2 MAC Hash Address Register 1 MACHASH1 Field Descriptions Back Off Test Register Bofftest Transmit Pacing Algorithm Test Register TpacetestBack Off Test Register Bofftest Field Descriptions Transmit Pause Timer Register Txpause Field Descriptions Receive Pause Timer Register RxpauseTransmit Pause Timer Register Txpause Receive Pause Timer Register Rxpause Field Descriptions Valid MAC Address Low Bytes Register MacaddrloMAC Address Low Bytes Register Macaddrlo Field Descriptions Valid Matchfilt Channel MACADDR0 MACADDR1 MACADDR2 MACADDR3 MACADDR4 MACADDR5 MAC Address High Bytes Register MacaddrhiMAC Index Register Macindex MAC Index Register Macindex Field Descriptions TXnHDP Receive Channel 0-7 Completion Pointer Register RXnCP Transmit Channel 0-7 Completion Pointer Register TXnCP Multicast Receive Frames Register Rxmcastframes Network Statistics RegistersGood Receive Frames Register Rxgoodframes Broadcast Receive Frames Register Rxbcastframes Receive Oversized Frames Register Rxoversized Receive CRC Errors Register RxcrcerrorsReceive Alignment/Code Errors Register Rxaligncodeerrors Pause Receive Frames Register Rxpauseframes Filtered Receive Frames Register Rxfiltered Receive Jabber Frames Register RxjabberReceive Undersized Frames Register Rxundersized Receive Frame Fragments Register Rxfragments Broadcast Transmit Frames Register Txbcastframes Receive QOS Filtered Frames Register RxqosfilteredReceive Octet Frames Register Rxoctets Good Transmit Frames Register Txgoodframes Transmit Single Collision Frames Register Txsinglecoll Pause Transmit Frames Register TxpauseframesDeferred Transmit Frames Register Txdeferred Transmit Collision Frames Register Txcollision Transmit Octet Frames Register Txoctets Transmit Underrun Error Register TxunderrunTransmit Carrier Sense Errors Register Txcarriersense Transmit Late Collision Frames Register Txlatecoll Submit Documentation Feedback Receive DMA Overruns Register Rxdmaoverruns Network Octet Frames Register Netoctets Appendix a Glossary Term Definition Physical Layer Definitions Reference Additions/Modifications/Deletions Document Revision History Products Applications DSPRfid