Texas Instruments TMS320DM643X DMP manual Buffer Length

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Peripheral Architecture

2.5.5.4Buffer Length

This 16-bit field is used for two purposes:

∙Before the descriptor is first placed on the receive queue by the application software, the buffer length field is first initialized by the software to have the physical size of the empty data buffer pointed to by the buffer pointer field.

∙After the empty buffer has been processed by the EMAC and filled with received data bytes, the buffer length field is updated by the EMAC to reflect the actual number of valid data bytes written to the buffer.

2.5.5.5Packet Length

This 16-bit field specifies the number of data bytes in the entire packet. This value is initialized to zero by the software application for empty packet buffers. The value is filled in by the EMAC on the first buffer used for a given packet. This is signified by the EMAC setting a start of packet (SOP) flag. The packet length is set by the EMAC on all SOP buffer descriptors.

2.5.5.6Start of Packet (SOP) Flag

When set, this flag indicates that the descriptor points to a packet buffer that is the start of a new packet. In the case of a single fragment packet, both the SOP and end of packet (EOP) flags are set. Otherwise, the descriptor pointing to the last packet buffer for the packet has the EOP flag set. This flag is initially cleared by the software application before adding the descriptor to the receive queue. This bit is set by the EMAC on SOP descriptors.

2.5.5.7End of Packet (EOP) Flag

When set, this flag indicates that the descriptor points to a packet buffer that is last for a given packet. In the case of a single fragment packet, both the start of packet (SOP) and EOP flags are set. Otherwise, the descriptor pointing to the last packet buffer for the packet has the EOP flag set. This flag is initially cleared by the software application before adding the descriptor to the receive queue. This bit is set by the EMAC on EOP descriptors.

2.5.5.8Ownership (OWNER) Flag

When set, this flag indicates that the descriptor is currently owned by the EMAC. This flag is set by the software application before adding the descriptor to the receive descriptor queue. This flag is cleared by the EMAC once it is finished with a given set of descriptors, associated with a received packet. The flag is updated by the EMAC on SOP descriptor only. So when the application identifies that the OWNER flag is cleared on an SOP descriptor, it may assume that all descriptors up to and including the first with the EOP flag set have been released by the EMAC. (Note that in the case of single buffer packets, the same descriptor will have both the SOP and EOP flags set.)

2.5.5.9End of Queue (EOQ) Flag

When set, this flag indicates that the descriptor in question was the last descriptor in the receive queue for a given receive channel, and that the corresponding receiver channel has halted. This flag is initially cleared by the software application prior to adding the descriptor to the receive queue. This bit is set by the EMAC when the EMAC identifies that a descriptor is the last for a given packet received (also sets the EOP flag), and there are no more descriptors in the receive list (next descriptor pointer is NULL).

The software application can use this bit to detect when the EMAC receiver for the corresponding channel has halted. This is useful when the application appends additional free buffer descriptors to an active receive queue. Note that this flag is valid on EOP descriptors only.

SPRU941A –April 2007Ethernet Media Access Controller (EMAC)/ 25

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Management Data Input/Output (MDIO)

 

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Contents Users Guide Submit Documentation Feedback Contents MAC Hash Address Register 1 MACHASH1 Appendix B Appendix aList of Figures Transmit Pacing Algorithm Test Register Tpacetest List of Tables Fifo Control Register Fifocontrol Field Descriptions Read This First Purpose of the Peripheral FeaturesEmac and Mdio Block Diagram Functional Block DiagramIndustry Standards Compliance Statement Signal DescriptionsClock Control Memory MapSignal Type Description Emac and Mdio SignalsEthernet Frame Format Ethernet Protocol OverviewEthernet Frame Description Field Bytes DescriptionProgramming Interface Ethernet’s Multiple Access ProtocolPacket Buffer Descriptors Typical Descriptor Linked List Basic Descriptor DescriptionTransmit and Receive Descriptor Queues Transmit and Receive Emac Interrupts Example 1. Transmit Buffer Descriptor in C Structure Format Transmit Buffer Descriptor FormatBuffer Pointer Next Descriptor PointerBuffer Offset Buffer LengthOwnership Owner Flag End of Packet EOP FlagEnd of Queue EOQ Flag Teardown Complete Tdowncmplt FlagReceive Buffer Descriptor Format Receive Buffer Descriptor Format#define Emacdscflagjabber Example 2. Receive Buffer Descriptor in C Structure FormatBuffer Length Alignment Error Alignerror Flag Code Error Codeerror FlagCRC Error Crcerror Flag Jabber FlagNo Match Nomatch Flag Emac Control ModuleInternal Memory Bus ArbiterInterrupt Control Mdio ModuleMdio Module Components Mdio Clock Generator PHY Register User AccessGlobal PHY Detection and Link State Monitoring Active PHY MonitoringMdio Module Operational Overview Writing Data To a PHY Register Initializing the Mdio ModuleReading Data From a PHY Register Example 3. Mdio Register Access Macros Example of Mdio Register Access CodeEmac Module Components Emac ModuleReceive DMA Engine Receive FifoTransmit DMA Engine Clock and Reset LogicTransmit Fifo MAC TransmitterData Reception Media Independent Interface MIIReceive Control Receive Inter-Frame IntervalIeee 802.3x-Based Receive Buffer Flow Control Collision-Based Receive Buffer Flow ControlCRC Insertion Transmit ControlAdaptive Performance Optimization APO Interpacket-Gap IPG EnforcementSpeed, Duplex, and Pause Frame Support Transmit Flow ControlPacket Receive Operation Receive DMA Host ConfigurationReceive Channel Enabling Receive Address MatchingHost Free Buffer Tracking Hardware Receive QOS SupportReceive Channel Teardown Receive Frame Classification Promiscuous Receive ModeReceive Frame Treatment Receive Frame Treatment SummaryMiddle of Frame Overrun Treatment Receive OverrunMiddle of Frame Overrun Treatment Packet Transmit Operation Transmit DMA Host ConfigurationReceive and Transmit Latency Transmit Channel TeardownSoftware Reset Considerations Reset ConsiderationsTransfer Node Priority Initialization Hardware Reset ConsiderationsEnabling the EMAC/MDIO Peripheral Emac Control Module InitializationMdio Module Initialization Example 4. Emac Control Module Initialization CodeExample 5. Mdio Module Initialization Code Emac Module Initialization Emac Module Interrupt Events and Requests Interrupt SupportTransmit Packet Completion Interrupts Receive Packet Completion InterruptsStatistics Interrupt Host Error InterruptMdio Module Interrupt Events and Requests User Access Completion InterruptLink Change Interrupt Proper Interrupt ProcessingEmulation Considerations Power ManagementEmulation Control Emac Control Module Registers Emac Control Module Interrupt Control Register EwctlAcronym Register Description Bit FieldEmac Control Module Interrupt Timer Count Register Ewinttcnt Management Data Input/Output Mdio Registers Mdio Version Register VersionMdio Version Register Version Field Descriptions Mdio Control Register Control Field Descriptions Mdio Control Register ControlPHY Link Status Register Link PHY Acknowledge Status Register AlivePHY Acknowledge Status Register Alive Field Descriptions PHY Link Status Register Link Field DescriptionsNo Mdio link change event Will clear the event and writing a 0 has no effect No Mdio user command complete event USERINTMASKED0 and USERINTMASKED1 correspond to USERACCESS0 WS-0 Userintmaskclear Mdio User Access Register 0 USERACCESS0 Field Descriptions Mdio User Access Register 0 USERACCESS0Linksel Linkintenb Mdio User PHY Select Register 0 USERPHYSEL0Phyadrmon Bit Field Value DescriptionMdio User Access Register 1 USERACCESS1 Field Descriptions Mdio User Access Register 1 USERACCESS1Mdio User PHY Select Register 1 USERPHYSEL1 Mdio User PHY Select Register 1 USERPHYSEL1Ethernet Media Access Controller Emac Registers Offset Acronym Register Description Ethernet Media Access Controller Emac RegistersNetwork Statistics Registers Offset Acronym Register DescriptionTransmit Control Register Txcontrol Transmit Identification and Version Register TxidverTransmit Control Register Txcontrol Field Descriptions Transmit Teardown Register Txteardown Field Descriptions Transmit Teardown Register TxteardownTxtdnch Receive Control Register Rxcontrol Receive Identification and Version Register RxidverReceive Control Register Rxcontrol Field Descriptions Receive Teardown Register Rxteardown Field Descriptions Receive Teardown Register RxteardownRxtdnch TX7PEND Transmit Interrupt Status Unmasked Register TxintstatrawTransmit Interrupt Status Masked Register Txintstatmasked Transmit Interrupt Status Masked Register TxintstatmaskedTX7MASK Transmit Interrupt Mask Set Register TxintmasksetTransmit Interrupt Mask Clear Register Txintmaskclear Transmit Interrupt Mask Clear Register TxintmaskclearMAC Input Vector Register Macinvector Field Descriptions MAC Input Vector Register MacinvectorUserint Linkint Hostpend Statpend Rxpend TxpendRX7PEND Receive Interrupt Status Unmasked Register RxintstatrawReceive Interrupt Status Masked Register Rxintstatmasked Receive Interrupt Status Masked Register RxintstatmaskedRX7MASK Receive Interrupt Mask Set Register RxintmasksetReceive Interrupt Mask Clear Register Rxintmaskclear Receive Interrupt Mask Clear Register RxintmaskclearMAC Interrupt Status Masked Register Macintstatmasked MAC Interrupt Status Unmasked Register MacintstatrawHostpend Statpend MAC Interrupt Mask Clear Register Macintmaskclear MAC Interrupt Mask Set Register MacintmasksetHostmask Statmask HostmaskRxcmfen Rxpasscrc Rxqosen RxnochainRxcsfen Rxcefen Rxcafen RxpromchFrames containing errors are filtered Receive multicast channel select RXCH7EN Receive Unicast Enable Set Register RxunicastsetReceive Unicast Clear Register Rxunicastclear Receive Unicast Clear Register RxunicastclearReceive Buffer Offset Register Rxbufferoffset Receive Maximum Length Register RxmaxlenReceive Maximum Length Register Rxmaxlen Field Descriptions Reserved RX nFLOWTHRESH FFh RxfilterthreshReceive Channel 0-7 Free Buffer Count Register RXnFREEBUFFER MAC Control Register Maccontrol Field Descriptions MAC Control Register MaccontrolLoopback Sent. Full-duplex mode no outgoing pause frames are sentMAC Status Register Macstatus Field Descriptions MAC Status Register MacstatusBit Field Value Description MAC Status Register Macstatus Field DescriptionsFifo Control Register Fifocontrol Emulation Control Register EmcontrolEmulation Control Register Emcontrol Field Descriptions Fifo Control Register Fifocontrol Field DescriptionsSoft Reset Register Softreset MAC Configuration Register MacconfigMAC Configuration Register Macconfig Field Descriptions Soft Reset Register Softreset Field DescriptionsMAC Source Address High Bytes Register Macsrcaddrhi MAC Source Address Low Bytes Register MacsrcaddrloMAC Hash Address Register 2 MACHASH2 MAC Hash Address Register 1 MACHASH1MAC Hash Address Register 1 MACHASH1 Field Descriptions MAC Hash Address Register 2 MACHASH2 Field DescriptionsTransmit Pacing Algorithm Test Register Tpacetest Back Off Test Register BofftestBack Off Test Register Bofftest Field Descriptions Transmit Pause Timer Register Txpause Receive Pause Timer Register RxpauseReceive Pause Timer Register Rxpause Field Descriptions Transmit Pause Timer Register Txpause Field DescriptionsMAC Address High Bytes Register Macaddrhi MAC Address Low Bytes Register MacaddrloMAC Address Low Bytes Register Macaddrlo Field Descriptions MAC Index Register Macindex Field Descriptions MAC Index Register MacindexMacindex TX nHDP Receive Channel 0-7 Completion Pointer Register RXnCP Transmit Channel 0-7 Completion Pointer Register TXnCPGood Receive Frames Register Rxgoodframes Network Statistics RegistersBroadcast Receive Frames Register Rxbcastframes Multicast Receive Frames Register RxmcastframesReceive Alignment/Code Errors Register Rxaligncodeerrors Receive CRC Errors Register RxcrcerrorsPause Receive Frames Register Rxpauseframes Receive Oversized Frames Register RxoversizedReceive Undersized Frames Register Rxundersized Receive Jabber Frames Register RxjabberReceive Frame Fragments Register Rxfragments Filtered Receive Frames Register RxfilteredReceive Octet Frames Register Rxoctets Receive QOS Filtered Frames Register RxqosfilteredGood Transmit Frames Register Txgoodframes Multicast Transmit Frames Register Txmcastframes Broadcast Transmit Frames Register TxbcastframesPause Transmit Frames Register Txpauseframes Deferred Transmit Frames Register TxdeferredTransmit Single Collision Frames Register Txsinglecoll Transmit Underrun Error Register TxunderrunTransmit Multiple Collision Frames Register Txmulticoll Transmit Late Collision Frames Register TxlatecollTransmit Octet Frames Register Txoctets Transmit Carrier Sense Errors Register TxcarriersenseTransmit and Receive 64 Octet Frames Register FRAME64 Network Octet Frames Register Netoctets Receive DMA Overruns Register Rxdmaoverruns Appendix a Glossary Term Definition Table A-1. Physical Layer DefinitionsReference Additions/Modifications/Deletions Table B-1. Document Revision HistoryDSP Products Applications
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