Texas Instruments TMS320DM643X DMP Basic Descriptor Description, Typical Descriptor Linked List

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		Peripheral Architecture
		Table 3. Basic Descriptor Description
Word Offset	Field	Field Description
0	Next Descriptor	The next descriptor pointer is used to create a single linked list of descriptors. Each descriptor
	Pointer	describes a packet or a packet fragment. When a descriptor points to a single buffer packet
		or the first fragment of a packet, the start of packet (SOP) flag is set in the flags field. When a
		descriptor points to a single buffer packet or the last fragment of a packet, the end of packet
		(EOP) flag is set. When a packet is fragmented, each fragment must have its own descriptor
		and appear sequentially in the descriptor linked list.
1	Buffer Pointer	The buffer pointer refers to the actual memory buffer that contains packet data during
		transmit operations, or is an empty buffer ready to receive packet data during receive
		operations.
2	Buffer Offset	The buffer offset is the offset from the start of the packet buffer to the first byte of valid data.
		This field only has meaning when the buffer descriptor points to a buffer that actually contains
		data.
	Buffer Length	The buffer length is the actual number of valid packet data bytes stored in the buffer. If the
		buffer is empty and waiting to receive data, this field represents the size of the empty buffer.
3	Flags	The flags field contains more information about the buffer, such as, is it the first fragment in a
		packet (SOP), the last fragment in a packet (EOP), or contains an entire contiguous Ethernet
		packet (both SOP and EOP). The flags are described in Section 2.5.4 and Section 2.5.5.
	Packet Length	The packet length only has meaning for buffers that both contain data and are the start of a
		new packet (SOP). In the case of SOP descriptors, the packet length field contains the length
		of the entire Ethernet packet, regardless if it is contained in a single buffer or fragmented over
		several buffers.

Figure 5. Typical Descriptor Linked List

pNext

pBuffer

	0		60

	SOP EOP		60

	pNext
	pBuffer
	pBuffer

	0		512
	SOP		1514


	pNext
	pBuffer
	pBuffer
	0		502

	−−−		−−−


	pNext
	pBuffer
	pBuffer

	0		500

	EOP		−−−


	pNext (NULL)
	pBuffer
	pBuffer

	0		1514

	SOP EOP		1514

Packet A 60 bytes

Packet B

Fragment 1

512 bytes

Packet B

Fragment 2

502 bytes

Packet B

Fragment 3

500 bytes

Packet C

1514 bytes

SPRU941A –April 2007Ethernet Media Access Controller (EMAC)/ 17

Submit Documentation Feedback	Management Data Input/Output (MDIO)

Image 17

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 Map Signal Type Description Emac and Mdio SignalsEthernet Frame Format Ethernet Protocol OverviewEthernet Frame Description Field Bytes DescriptionPacket Buffer Descriptors Ethernet’s Multiple Access ProtocolProgramming Interface 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 ArbiterMdio Module Components Mdio ModuleInterrupt Control Mdio Clock Generator PHY Register User AccessGlobal PHY Detection and Link State Monitoring Active PHY MonitoringMdio Module Operational Overview Reading Data From a PHY Register Initializing the Mdio ModuleWriting Data To 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 MatchingReceive Channel Teardown Hardware Receive QOS SupportHost Free Buffer Tracking 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 TeardownTransfer Node Priority Reset ConsiderationsSoftware Reset Considerations Initialization Hardware Reset ConsiderationsEnabling the EMAC/MDIO Peripheral Emac Control Module InitializationExample 5. Mdio Module Initialization Code Example 4. Emac Control Module Initialization CodeMdio Module Initialization 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 Control Power ManagementEmulation Considerations Emac Control Module Registers Emac Control Module Interrupt Control Register EwctlAcronym Register Description Bit FieldEmac Control Module Interrupt Timer Count Register Ewinttcnt Mdio Version Register Version Field Descriptions Mdio Version Register VersionManagement Data Input/Output Mdio Registers 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 Field Descriptions Transmit Identification and Version Register TxidverTransmit Control Register Txcontrol Txtdnch Transmit Teardown Register TxteardownTransmit Teardown Register Txteardown Field Descriptions Receive Control Register Rxcontrol Field Descriptions Receive Identification and Version Register RxidverReceive Control Register Rxcontrol Rxtdnch Receive Teardown Register RxteardownReceive Teardown Register Rxteardown Field Descriptions 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 RxintmaskclearHostpend Statpend MAC Interrupt Status Unmasked Register MacintstatrawMAC Interrupt Status Masked Register Macintstatmasked 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 Maximum Length Register Rxmaxlen Field Descriptions Receive Maximum Length Register RxmaxlenReceive Buffer Offset Register Rxbufferoffset 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 DescriptionsBack Off Test Register Bofftest Field Descriptions Back Off Test Register BofftestTransmit Pacing Algorithm Test Register Tpacetest Transmit Pause Timer Register Txpause Receive Pause Timer Register RxpauseReceive Pause Timer Register Rxpause Field Descriptions Transmit Pause Timer Register Txpause Field DescriptionsMAC Address Low Bytes Register Macaddrlo Field Descriptions MAC Address Low Bytes Register MacaddrloMAC Address High Bytes Register Macaddrhi Macindex MAC Index Register MacindexMAC Index Register Macindex Field Descriptions 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 RxfilteredGood Transmit Frames Register Txgoodframes Receive QOS Filtered Frames Register RxqosfilteredReceive Octet Frames Register Rxoctets 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 and Receive 64 Octet Frames Register FRAME64 Transmit Carrier Sense Errors Register TxcarriersenseTransmit Octet Frames Register Txoctets 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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