Lantronix DSTni-EX manual Token Register

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Token Register

The Token register performs USB transactions when in host mode (HOST_MODE_EN=1). When the host microprocessor wants to execute a USB transaction to a peripheral, it writes the TOKEN type and endpoint to this register. After this register is written, the USB begins the specified USB transaction to the address contained in the Address register.

The host microprocessor must always check that the TOKEN_BUSY bit in the control register is not set before performing a write to the Token register. This ensures that token commands are not overwritten before they execute.

The Address register is also used when performing a token command and therefore must also be written before the Token register. The Address register is used to correctly select the USB peripheral address that will be transmitted by the token command.

The SOF Threshold register is used only in host mode. When host mode is enabled, the 14-bit SOF counter counts the interval between SOF frames. The SOF must be transmitted every 1us so the SOF counter is loaded with a value of 12000. When the SOF counter reaches zero, a Start-of-Frame (SOF) token is transmitted. The SOF Threshold register programs the number of USB byte times before the SOF to stop initiating token packet transactions. This register must be set to a value that ensures that other packets are not actively being transmitted when the SOF timer counts to zero. When the SOF counter reaches the threshold value, token transmission stops until after the SOF has been transmitted. The value programmed into the Threshold register must reserve enough time to ensure that the worst case transaction will complete. In general, the worst case transaction is a IN token, followed by a data packet from the target, followed by the response from the host. The actual time required is a function of the maximum packet size on the bus. Typical values for the SOF threshold are:

64 byte packets=74

32 byte packets=42

16 byte packets=26

8 byte packets=18

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Contents Section Five DSTni-EX User GuidePage Master Distributor Copyright & TrademarkLantronix Technical SupportWarranty 3 I2C Controller Contents1 About This User Guide 2 SPI Controller5 CAN Controllers List of TablesTable 3-17. Clock Control Register List of Figures 1 About This User Guide Notes Notes are information requiring attention Intended AudienceConventions Navigating OnlineOrganization DSTni SPI Controller 2 SPI ControllerTheory of Operation SPI BackgroundTable 2-1. SPI Controller Register Summary SPI Controller Register SummaryTable 2-2. SPIDATA Register SPI Controller Register DefinitionsSPIDATA Register RESETWire-O CTL RegisterInterrupt Request Enable Phase SelectInterrupt Request SPISTAT RegisterTable 2-6. SPISTAT Register Table 2-7. SPISTAT Register DefinitionsTable 2-8. SPISSEL Register SPISSEL RegisterTable 2-10. BCNT Bit Settings SelectO SignalTable 2-12. DVDCNTRLO Register Definitions DVDCNTRLO RegisterDVDCNTRHI Table 2-11. DVDCNTRLO Register3 I2C Controller FeaturesI2C Background Block DiagramFigure 3-1. DSTni I2C Controller Block Diagram Operating Modes I2C ControllerMaster Transmit Mode Microprocessor Response Table 3-1. Master Transmit Status CodesCode I2C StateTable 3-2. Codes After Servicing Interrupts Master Transmit Servicing the InterruptMaster Receive Mode Transmitting Each Data ByteTable 3-3. Status Codes After Each Data Byte Transmits All Bytes Transmit CompletelyTable 3-4. Master Receive Status Codes Table 3-5. Codes After Servicing Interrupt Master Receive Table 3-6. Codes After Receiving Each Data Byte Receiving Each Data ByteSlave Transmit Mode Slave Receive Mode Bus Arbitration Bus Clock ConsiderationsBus Clock Speed Clock SynchronizationTable 3-7. I 2C Controller Register Summary Programmer’s ReferenceI2C Controller Register Summary Resetting the I2C ControllerTable 3-8. Slave Address Register I2C Controller Register DefinitionsSlave Address Register General Call Address EnableTable 3-10. Data Register Data RegisterExtended Slave Address Control RegisterTable 3-12. Control Register Table 3-13. Control Register DefinitionsTable 3-14. Status Register Status RegisterTable 3-16. Status Codes Table 3-15. Status Register DefinitionsStatus Code Table 3-17. Clock Control Register Clock Control RegisterTable 3-18. Clock Control Register Definitions Table 3-22. Software Reset Register Definitions Software Reset RegisterExtended Slave Address Register Table 3-21. Software Reset Register4 USB Controller Serial Interface Engine USB BackgroundUSB Interrupt USB CoreBuffer Descriptor Table USB Hardware/Software InterfaceDigital Phase Lock Loop Logic Microprocessor InterfaceRx vs. Tx as a Target Device or Host Figure 4-1. Buffer Descriptor TableTable 4-3. 16-Bit USB Address Definitions Table 4-1. USB Data DirectionAddressing BDT Entries Table 4-2. 16-Bit USB AddressTable 4-5. USB Buffer Descriptor Format Table 4-4. BDT Data Used by USB Controller and MicroprocessorUSB Controller Determines… Microprocessor Determines…USB Ownership Table 4-6. USB Buffer Descriptor Format DefinitionsBD Owner DATA0/1 Transmit or ReceiveFigure 4-2. USB Token Transaction USB TransactionTable 4-7. USB Register Summary USB Register SummaryDedicated to host mode Table 4-9. 16- Interrupt Status Register Definitions USB Register DefinitionsInterrupt Status Register Table 4-8. Interrupt Status RegisterUSB Reset Enable/Disable USBRST InterruptSleep Timer Error ConditionTable 4-10. Error Interrupt Status Register Error RegisterTable 4-11. 16- Error Interrupt Status Register Definitions PID check field failed Error interrupt with two functionsData Field Received Not 8 Bits CRC16 FailureTable 4-13. Status Register Definitions Live USB Differential Receiver JSTATE SignalLive USB Single Ended Zero Signal Table 4-12. Status RegisterBDT PDD Reset USB Reset SignalHost Mode Enable valid for host mode only Resume SignalingTable 4-14. Address Register Address RegisterTable 4-15. 16- Address Register Definitions Frame Number Frame Number RegistersTable 4-16. Frame Number Register Table 4-17. Frame Number Register DefinitionsToken Register Table 4-20. Valid PID Tokens Endpoint for Token CommandTable 4-18. Token Register Table 4-19. Token Register DefinitionsTable 4-22. Endpoint Control Register Definitions Endpoint Control RegistersEndpoint Enable Table 4-21. Endpoint Control RegistersTable 4-23. Endpoint Control Register Definitions Host Mode OperationFigure 3. Enable Host Mode and Configure a Target Device Sample Host Mode OperationsFigure 4. Full-Speed Bulk Data Transfers to a Target Device Figure 4-5. Pull-up/Pull-down USB USB Pull-up/Pull-down ResistorsClock CLK USB Interface SignalsUSB Output Enable HOST Mode Enable5 CAN Controllers CANBUS Background Arbitration and Error CheckingData Exchanges and Communication Table 5-1. Bit Rates for Different Cable Lengths CANBUS Speed and LengthRegister CAN Register SummariesRegister Summary Hex OffsetRegister Table 5-4. Detailed CAN Register Map Detailed CAN Register MapHex Offset Acceptance Filter Enable RegisterRegister Sending a Message CAN Register DefinitionsTX Message Registers Figure 5-1. TX Message RoutingTable 5-7. TxMessage0Data Tx Message RegistersTable 5-5. TxMessage0ID28 Table 5-6. TxMessage0ID12Message Data Table 5-12. TxMessage0Ctrl FlagsTable 5-13. TxMessage0 Register Definitions Message Identifier for Both Standard and Extended MessagesFigure 5-2. RX Message Routing RX Message RegistersTable 5-16. RxMessageID12 Rx Message RegistersTable 5-14. RxMessageID28 Table 5-15. Rx Message ID28 Register DefinitionsTable 5-23. Rx Message Data 23 Register Definitions Table 5-20. Rx Message DataTable 5-21. Rx Message Data 39 Register Definitions Table 5-22. Rx Message DataTable 5-29. Rx Message Msg Flags Register Definitions Table 5-26. RxMessage RTRTable 5-27. Rx Message RTR Register Definitions Table 5-28. Rx Message Msg FlagsTable 5-32. Error Status Error Count and Status RegistersTable 5-30. Tx/Rx Error Count Table 5-31. Tx\Rx Error Count Register Definitionstxlevel10 Table 5-34. Tx/Rx Message Level RegisterTable 5-35. Tx/Rx Message Level Register Definitions rxlevel10Format Error Interrupt FlagsNote The reset value of this register’s bits is indeterminate CRC ErrorBus Off State − int2n group error interrupts Interrupt Enable RegistersTable 5-38. Interrupt Enable Registers Table 5-39. Interrupt Enable Register DefinitionsOverload Condition − int3n group diagnostic interrupts CAN Operating ModeTable 5-40. Interrupt Enable Registers Table 5-41. Interrupt Enable Register DefinitionsTable 5-42. Bit Rate Divisor Register CAN Configuration RegistersConfiguration Bit Rate Figure 5-3. CAN Operating ModeCfgsjw Table 5-44. Configuration RegisterTable 5-45. Configuration Register Definitions Overwrite Last Messagetime quanta TQ Bit Timetseg1 + tseg2 +Table 5-48. Acceptance Mask 0 Register Acceptance Filter and Acceptance Code MaskTable 5-46. Acceptance Filter Enable Register Table 5-47. Acceptance Filter Enable Register DefinitionsD5556 Table 5-50. Acceptance Mask Register IDTable 5-51. Acceptance Mask Register ID12 Definitions Table 5-52. Acceptance Mask Register DataTable 5-57. Acceptance Mask Register ID12 Definitions Table 5-54. Acceptance Code RegisterTable 5-55. Acceptance Code Register Definitions Table 5-56. Acceptance Mask Register ID12Table 5-61. Arbitration Lost Capture Register Definitions CANbus AnalysisArbitration Lost Capture Register Table 5-60. Arbitration Lost Capture RegisterErrorcode Error Capture RegisterTable 5-62. Error Capture Register Table 5-63. Error Capture Register DefinitionsStuff Bit Inserted Table 5-65. Error Capture Register DefinitionsFrame Reference Register Table 5-64. Frame Reference RegisterFigure 5-5. CAN Bus Interface CAN Bus InterfaceInterface Connections Figure 5-6. CAN Connector+24V Figure 5-7. Power for CAN+5CAN GNDCAN0.01uf Figure 5-8. CAN Transceiver and Isolation Circuits