Freescale Semiconductor MPC860T Receive Buffer Size Register Rbuffsize, Describes Xdesstart Þelds

Page 38

Freescale Semiconductor, Inc.

Freescale Semiconductor, Inc.

Bits

0

1

2

3

4

5

 

6

 

7

 

8

 

9

10

11

12

13

14

 

15

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Field

 

 

 

 

 

 

 

 

X_DES_START

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reset

 

 

 

 

 

 

 

 

 

UndeÞned

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R/W

 

 

 

 

 

 

 

 

 

Read/write

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Addr

 

 

 

 

 

 

 

 

 

0xE14

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bits

16

17

18

19

20

21

 

22

 

23

 

24

 

25

26

27

28

29

30

 

31

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Field

 

 

 

 

 

 

X_DES_START

 

 

 

 

 

 

 

 

00

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reset

 

 

 

 

 

 

 

 

 

UndeÞned

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

R/W

 

 

 

 

 

 

 

 

 

Read/write

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Addr

 

 

 

 

 

 

 

 

 

0xE16

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 6-6. X_DES_START Register

Table 6-7 describes X_DES_START Þelds.

Table 6-7. X_DES_START Field Descriptions

Bits

Name

Description

 

 

 

0Ð29

X_DES_START

Pointer to start of TxBD queue.

 

 

 

30Ð31

Ñ

Reserved. Should be written to zero by the host processor.

 

 

 

6.2.7 Receive Buffer Size Register (R_BUFF_SIZE)

The R_BUFF_SIZE register, shown in Figure 6-7, is like the MRBLR register used by other protocols. It speciÞes the maximum size of all receive buffers. It does not reset and must be initialized by the user. Because the maximum frame is 2047 bytes, only bits 21Ð27 are used. This value should take into consideration that the receive CRC is always written into the last receive buffer. To support frame lengths up to 1520 bytes, R_BUFF_SIZE must be at least 0x0000_05F0. To ensure that R_BUFF_SIZE is a multiple of 16, bits 28Ð31 are forced to zeros. Using buffers smaller than the recommended minimum 256 bytes increases the risk of receive FIFO overßow due to the overhead of opening and closing buffers.

6-6MPC860T (Rev. D) Fast Ethernet Controller Supplement MOTOROLA

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Contents MPC860T Rev. D Fast Ethernet Controller Freescale Semiconductor, IncMotorola Literature Distribution Centers Contents Parallel I/O Ports Contents Paragraph Title Number Illustrations Title NumberViii MPC860T Rev. D Fast Ethernet Controller Supplement Tables Number Lists signiÞcant changes between revisions of this document Document Revision HistoryOverview Document Revision HistoryFeatures Comparison with the MPC8601 MPC860TBlock Diagram Fast Ethernet Controller Embedded PowerPC Processor CoreSystem Interface Unit SIU Glueless System Design SIU Interrupt ConÞgurationInc Name Pin Description Signal DescriptionsFEC Signal Descriptions RXD3 L1RSYNCBMiimdc MiitxerREJECT4 REJECT3MIITXD2 MIITXD1Freescale Semiconductor, Inc Transceiver Connection MII SignalsSignal Description FEC Signal Name This chapter discusses the operation of the FECTXD0 Serial Mode Connections to the External TransceiverFEC Frame Transmission RXD0FEC Frame Reception Ethernet Address Recognition FEC Command SetCAM Interface Hash Table Algorithm Rcntrlprom =Inter-Packet Gap Time Collision HandlingReception Errors Ethernet Error-Handling ProcedureTransmission Errors Internal and External LoopbackReception Errors Chapter Parallel I/O Ports Port D Pin FunctionsPort D Registers Enabling MII ModeSignal Function Shows the port D pin assignmentsSdma Registers CLKFRZ Faid RAID Describes Sdcr ÞeldsSdcr Field Descriptions BitsFEC Parameter RAM Memory Map Parameter RAMBrießy describes each enter in the FEC parameter RAM Address Name Description SectionRAM Perfect Match Address Low Register Addrlow Describes the Addrlow Þelds RAM Perfect Match Address High AddrhighRAM Hash Table High Hashtablehigh Describes the Addrhigh ÞeldsHashtablehigh Field Descriptions RAM Hash Table Low HashtablelowDescribes Hashtablehigh Þelds HashhighDescribes Hashtablelow Þelds Beginning of RxBD Ring RdesstartBeginning of TxBD Ring Xdesstart Describes Rdesstart ÞeldsXdesstart Field Descriptions Receive Buffer Size Register RbuffsizeDescribes Xdesstart Þelds Describes Rbuffsize Þelds Spare Fecpin Etheren Reset MUXEthernet Control Register Ecntrl Rbuffsize Field DescriptionsEcntrl Field Descriptions Interrupt Event IEVENT/Interrupt Mask Register ImaskDescribes Ecntrl Þelds Fecpinmux10. IEVENT/IMASK Field Descriptions Ethernet Interrupt Vector Register IvecRfint to notify at the end of frame Hberr11. Ivec Field Descriptions RxBD Active Register Rdesactive11 describes Ivec Þelds Ilevel12. Rdesactive Field Descriptions TxBD Active Register Xdesactive12 describes Rdesactive Þelds 13. Xdesactive Field Descriptions MII Management Frame Register Miidata13 describes Xdesactive Þelds 14 describes Miidata Þelds 14. Miidata Field Descriptions15. Miispeed Field Descriptions MII Speed Control Register Miispeed15 describes Miispeed Þelds Dispreamble Miispeed16. Programming Examples for Miispeed Register Fifo Receive Bound Register Rbound17 describes Rbound Þelds 17. Rbound Field Descriptions18 describes Rñfstart Þelds Fifo Receive Start Register RfstartTransmit Watermark Register Xwmrk 18. Rfstart Field Descriptions19. Xwmrk Field Descriptions Fifo Transmit Start Register Xfstart19 bit Þeld descriptions for Xwmrk 20. Xfstart Field Descriptions DMA Function Code Register Funcode20 describes Xfstart Þelds DATABO0 DATABO1 DESCBO0 DESCBO1 FC1 FC2 FC321. Funcode Field Descriptions Receive Control Register Rcntrl21 describes Funcode Þelds Descbo22. Rcntrl Field Descriptions Receive Hash Register Rhash22 describes Rcntrl Þelds Bcrej24 describes Xcntrl Þelds Transmit Control Register Xcntrl22 describes Rhash Þelds 23. Rhash Field DescriptionsHardware Initialization User Initialization before Setting EcntrletherenInitialization Sequence 25. Hardware InitializationUser Initialization after Asserting Ecntrletheren 27. User Initialization before Setting EcntrletherenDescriptor Controller Initialization Step DescriptionEthernet Receive Buffer Descriptor RxBD 27. User Initialization after Setting EcntrletherenBuffer Descriptors BDs StepRO1 RO2 Data Length RxBD format is shown in Table27. Receive Buffer Descriptor RxBD Field Description RO129. Transmit Buffer Descriptor TxBD Field Descriptions Ethernet Transmit Buffer Descriptor TxBD29 describes TxBD Þelds TO1 TO2 DEF CSLXcntrlhbc = DataFreescale Semiconductor, Inc MII Receive Signal Timing RXD30, RXDV, RXER, Rxclk DC Electrical CharacteristicsAC Electrical Characteristics Electrical SpeciÞcationsMII Transmit Signal Timing MII Transmit Signal Timing TXD30, TXEN, TXER, TxclkMII Receive Signal Timing Num Characteristic Min Max UnitTxen Txer MII Async Inputs Signal Timing CRS, COLMII Async Inputs Signal Timing CRS, COLShows the MII serial management channel timing diagram MII Serial Management Channel TimingFollowing pins are marked as spare on MPC860T Pin AssignmentsFreescale Semiconductor, Inc Freescale Semiconductor, Inc For More Information On This Product
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