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START first foil

START first foil. ISDN. USB based Microcontroller in Telecom Peripherals for PC's. ...the interfacing solution. Agenda. USB basics Why USB Bus structure Enumeration, speed Layer model Physical interface Transfer, transaction, packet. USB - ISDN Terminal Adapter (TA)

justine-gilmore
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START first foil

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  1. START first foil

  2. ISDN USB based Microcontroller in Telecom Peripherals for PC's ...the interfacing solution

  3. Agenda • USB basics • Why USB • Bus structure • Enumeration, speed • Layer model • Physical interface • Transfer, transaction, packet • USB - ISDN Terminal Adapter (TA) • Standard TA (PC ISDN card) - USB TA • Endpoints usage, ISDN data format • Hardware implementation, Buffering • B-channel performance • Layer model USB TA  PC ISDN card • D-channel signalization through USB • D-channel performance • Hardware platform, tools • SAB-C541U

  4. Siemens / USBthe interfacing solution Universal Serial Bus

  5. Why USB ? • Ease of Use • Plug and Play capabilities for “Outside the Box” peripherals Youwanna more?! Universal Serial Bus

  6. ATTRIBUTES PERFORMANCE APPLICATIONS USB Target Applications Very Low cost Ease of Use Dynamic Attach-Detach Multiple Peripherals LOW SPEED 10 - 100 Kb/s Interactive Devices (Game, VR) USB USB focus on LOW COST, HIGH VOLUME applications! Low cost Guaranteed Latency Higher Bandwidth Ease of Use ISDN, POTS, PBX, Audio, Imaging, Bulk Devices MEDIUM SPEED 500Kb/s - 10Mb/s 1394+"firewire" Video Disk LAN High Bandwidth Very Low Latency Ease of Use HIGH SPEED 50 - 1000 Mb/s Universal Serial Bus

  7. USB in 1996: Initially introduced as an additional connector for new applications. USB Keyboard Serial Port Sound/Game Ports Modem LAN Mouse USB Future: The PC evolves into a simpler, easier to use appliance. Parallel Port Graphics Port SCSI Port USB USB USB Telephony, Modem, Keyboard, Mouse,Game ports, Serial ports Device,Digital Audio, Printer, Scanner Graphics Port LAN PC Connectivity Vision Universal Serial Bus

  8. HOST/HUB PC HUB Monitor HUB Kbd USB Pen Mouse Speaker Mic Phone Hardware Overview... • Topology • Tiered Star (Distributes Connectivity Points) • 127 logical connections (upto 5 meters per segment) • Upto 6 tiers • ... Universal Serial Bus

  9. ...Topology... • Host • One PC host per system • Hub • Provides connecting ports, power, terminations • Self-Powered or Bus Powered • Device, Function and End-points • Device is a collection of function(s) • Function is a collection of end-points • Upto 127 functions and 16 end-points per function Universal Serial Bus

  10. Host Host Root Hub Root Hub Device Device HUB HUB Device Device Device Device Device Device HUB HUB Device Device Device Device USB Configuration ProcessEnumeration • Host Software is responsible for Device configuration • Hot Plug and Play feature • Device attachment on Hub port • Device is detected • Downstream port is enabled • Configuration of Device by Host • Process of Configuration is accomplished via Control Transfers Universal Serial Bus, details

  11. Hardware Overview • Bus transactions • Speed: 12Mbps full-speed 1.5Mbps low-speed • Isochronous and Asynchronous • Media access controlled by host • Configuration, Hot Plug-And-Play • Dynamic insertion-removal • Autoconfiguration on change • Physical Layer • 2-wire differential signaling, NRZI coded with bit stuffing • Supply Sourcing +5V • Signaling at CMOS 3.3V • 4 pin connector, 4 wire cable Universal Serial Bus

  12. Device Abstractions... • Device • Common features and interactions of devices • Typically controlled by system software • End Point • Ultimate data source or sink at the device end • Each endpoint is unidirectional and has a transfer type associated with it‘s Peripheral • Function • Highest level I/F between device driver and function Universal Serial Bus

  13. Device Function Function Abstraction Driver Endpoint Endpoint Endpoint USB USB Device Device Abstraction Software I/F Host USB Physical Connect Controller Hardware ...Device Abstractions Device, like modem, keyboard mouse, etc PC Universal Serial Bus

  14. USBTransfer types • Control (e.g.: configuration, messages) • bursty, host initiated (bus management, configuration) • guaranteed bandwith of max. 10% • error-free data delivery guaranteed • Interrupt (e.g.: mouse, joystick....) • small bursty, low bandwidth required • error-free data delivery guaranteed • polling is used (by host) to check for "interrupt events” • polling intervall programmable. From 1ms to 255ms (FS) 10ms to 255ms (LS) • Isochronous (e.g.: audio, telephony.....) • for data which need to be periodically sent • predictable latency on data delivery. • no error check, error-free data delivery is not guaranteed • Bulk (e.g.: printer, scanner, still camera.....) • non periodic, bursty, ideal for large amounts of data • error-free data delivery guaranteed ...basics

  15. Bulk Control Frame = 1ms Stereo Audio SOF Telephony low-speed SOF Bulk Isochronous Interrupt any LS device like keyboard, mouse, etc. USB Frame Modelexample printer printer ...basics

  16. HUB / DEVICE HOST PC / HUB CABLE connector 'upstream' CABLE connector 'downstream' Power pair max. 5m Differential Signal pair Connectors and Cables • Connectors • 4-Position with shielded housing • Positive Retention • Blind Mating Capabilities Universal Serial Bus

  17. Downstream Connectivity Upstream Connectivity Hub Repeater Hub Repeater Disabled Port Enabled Ports USB Hub Function • Port Control • Connection detect • Port Enable/ Disable • Reset/ Resume Signaling • Data Switch • Signal Regeneration • Robustness/ Recovery • Power Distribution Universal Serial Bus

  18. Power Distribution • Significant capability of USB • Eliminate wall adaptors • Hubs may be self-powered or bus-powered • Two current levels: 100 & 500 mA • Overcurrent protection for safety • Wire gauge options: 20-28 AWG • Suspend • All devices support suspend • Enter suspend state after seeing idle bus for 3 ms • Suspend current  500 A from bus • Resume • USB devices can cause “remote wake-up”e.g. Modem wakes up the system Universal Serial Bus

  19. 4.65V (min) 4.40V (min) Bus-Powered Host or Bus-Powered Hub Function Powered Hub 4.0V (as a resulting low value) Voltage Drop • Voltage drop per wire/connector: 0.125 V • Budget for power switch: 0.100 V Universal Serial Bus

  20. Data Signaling • Bi-directional, half-duplex link • Embedded clock and data • Differential signal pair • 12 Mbit / sec Full Speed (FS) bit rate • 1.5 Mbit / sec Low Speed (LS) bit rate Universal Serial Bus

  21. Low Speed • 1.5 Mb/s • Unshielded, untwisted cable • Saves EMI suppression costs • 1.5% Frequency tolerance • Driver characteristics • Rise/ Fall time: Min 75ns, Max 300ns • Required on low speed functions and on the downstream ports of Hubs • Allows very-low-cost devices to be built without compromising data rate for faster devices • Mice, keyboards, most user interface peripherals don’t need fast data rate • Eliminates need for shielded twisted pair cable (3 meters) • Allows use of less-expensive IC process technology Universal Serial Bus

  22. USB Connections and Terminations VCC R2 D+ D+ F.S./L.S. USB Transceiver F.S. USB Transceiver R1 Twisted Pair Shielded D- (45Outputs) D- ZO = 90±15% 5 Meters Max. (45Outputs) GND Hub Port 0 or Full Speed Function R1 Host or Hub Port R1 = 15K±5% R2 = 1.5K±5% GND D+ D+ F.S./L.S. USB Transceiver L.S. USB Transceiver VCC R1 Untwisted, Unshielded R2 D- (45Outputs) GND 3 Meters Max. (45Outputs) D- R1 R1 = 15K±5% R2 = 1.5K±5% Host or Hub Port Low Speed Function GND Universal Serial Bus

  23. Transfer n Transaction n-1 Transaction n-2 Transaction n-3 Transaction n-1 Transfer - Transaction - Packet (1) • Host Software initiates Transfer from or to a target USB Device • Host software splits up one Transfer into one or more Transactions • Transactions are set up based on the Device's characteristics (Packet Size, Transfer Type) Universal Serial Bus, details

  24. Transfer - Transaction - Packet (2) • Host Software schedules and executes Transactions during 1ms Frames • Each Frame consists of several Transactions from different Transfers Universal Serial Bus, details

  25. Transfer - Transaction - Packet (3) • Each Transaction consists of a series of packets • Token Packet defines the Type of Transaction • Data Packet carries the payload to or from a Device • Handshake Packet provides feedback about correct data transfer to sender Universal Serial Bus, details

  26. 8 bits 8 bits 7 bits 4 bits 5 bits 2 bits Device ENDP Sync. Packet ID CRC EOP Address Nr 8 bits 8 bits 11 bits 5 bits 2 bits Sync. Packet ID Frame Number CRC EOP 8 bits 8 bits 0-1023 bytes 16 bits 2 bits Sync. Packet ID Data Field CRC EOP 8 bits 8 bits 2 bits Sync. Packet ID EOP Packet Formats Token Packet SOF Token Packet Data Packet Handshake/ Low Speed Preamble Universal Serial Bus, details

  27. Data Packet from IN Packet from Host ACK Packet from Host USB Device to Host PID PID PID Sync EOP Sync Data Packet (Payload) EOP Sync EOP IN Token Data ACK ONE TRANSACTION IN Transaction without errors • Token Packetdefines the direction of the succeding Data Packet (here: IN = Data Packet from Device to Host) • Data Packetcarries the payload • Handshake Packetreports error free reception of Data Packet Universal Serial Bus, details

  28. Hand- Token Data Packet (8 bytes) shake one full speed transaction Hand- Preamble Token Preamble Data Packet (8 bytes) shake full low full low speed low speed speed speed speed Low Speed - Full Speed Transaction • Protocol overhead for FS and LS Transfers is 13 bytes Payload for FS and LS is 8 bytes • FS Transfer : 13 + 8 = 21 full speed bytes times • LS Transfer : 13 * 8 + 8 * 8 = 168 full speed byte times (excluding Preamble) • ~9,5% of bandwidth wasted Universal Serial Bus, details

  29. END last foil

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