Texas Instruments 4Q 2006 Universal Serial Bus USB, Speed, Transfer Type, USB-to-Serial Bridge

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USB Hub Controllers and Peripheral Devices 25

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Universal Serial Bus (USB)

The USB standard defines a bus product that requires a host controller and enables plug- and-play connectivity. The most recently released final specification, USB 2.0, defines high speed and allows complete backward compatibility with USB 1.1.

USB products fall into three categories: hubs, host controllers and peripherals. USB 1.1 sup- ported speeds of up to 12 Mbps and cables up to 5 meters long for these devices. USB

2.0extends the connection speed to 480 Mbps to support next-generation peripherals of higher-performance PCs and applications. USB 2.0 officially defines three speeds: low (1.5 Mbps), full (12 Mbps) and high (480 Mbps). The lowest speed is ideal for human interface devices such as a mouse, game pad or keyboard; while full speed is well suited for “data dumps” to the PC via digital still cameras, PDA cradles and flash-card readers. Modems, printers, scanners and storage drives are just a few of the items that can take advantage of USB’s highest speed specification.

The USB On-The-Go (OTG) supplement to USB

2.0specifies a new class of devices aimed at the portable market. USB OTG defines devices that can operate as standard USB peripherals when connected to a standard USB host controller.

However, these same devices can operate as reduced-function host controllers to support selected USB OTG peripheral devices. End-equipment manufacturers can specify what type of peripherals their devices will support when in OTG host mode. This new specification allows easy sharing of contact information between USB OTG PDAs and cell phones or printing of photographs directly from an OTG- enabled digital still camera without a PC.

Technical Information

Speed

•The USB 2.0 standard defines three speeds: low speed (LS) 1.5 Mbps, full speed (FS) 12 Mbps and high speed (HS) 480 Mbps. It requires full backward and forward compatibility for devices and

cables. All three modes offer both asyn- chronous and isochronous (real-time) data transmission over a simple and inexpensive 4-wire cable to meet requirements of peripherals including keyboards, mice, printers, speakers, scanners, external storage devices and digital still cameras.

Transfer Type

•USB 2.0 defines four types of transfers: bulk, control, interrupt and isochronous. Bulk transfer is intended for applications such as printers, scanners and mass storage, where latency isn’t critical but accuracy is. All devices must include control transfers for configuration. Interrupt transfer is for devices such as mice, keyboards and game pads that must receive the host’s or device’s attention periodically. Isochronous transfer offers guaranteed delivery time but no error- checking or automatic retransmission of data received with errors, making it the better choice for audio or video applications.

RS232/IrDA Serial-to-USB Converter

TUSB3410

Get samples, datasheets, EVMs and app reports at: www.ti.com/sc/device/TUSB3410

USB-to-Serial Bridge

The TUSB3410 provides an easy way to move a serial-based legacy device to a fast, flexible USB interface by bridging between a USB port and an enhanced UART serial port. The TUSB3410 contains all the necessary logic to communicate with the host computer using the USB bus.

Key Features

•USB full-speed-compliant: data rate of 12 Mbps

•8052 microcontroller with 16 Kbytes of RAM that can be loaded from the host

or from external onboard memory via an I2C bus

•Integrated, enhanced UART features including:

•

Programmable software/hardware flow

 

control

•

Automatic RS-485 bus transceiver

 

control, with and without echo

•

Software-selectable baud rate from

 

50 to 921.6 kbaud

•

Built-in, two-channel DMA

 

controller for USB/UART bulk I/O

• Evaluation module to jump-start USB

development or for use as a complete

USB-to-RS-232 converter

 

 

Out

 

 

SOUT

 

Host

 

 

 

 

 

 

Legacy

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TUSB3410

 

 

 

Serial

 

 

 

 

(PC or OTG DRD)

 

USB

 

 

 

 

 

 

SIN

Peripheral

 

 

 

 

 

 

 

 

 

 

 

In

 

 

 

 

 

 

TUSB3410 data flow.

Applications

•Handheld meters

•Health metrics/monitors

•Any legacy serial device that needs to be upgraded to USB

Texas Instruments 4Q 2006

Interface Selection Guide

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Page 24 Page 26
Contents Interface Selection Guide Interface Selection Guide Table of ContentsClock Distribution Circuits p Interface Selection GuideDesign Considerations LVDS, xECL, CMLTechnical Information Lvds Family of ProductsTexas Instruments 4Q Pecl Selection GuideLvds Selection Guide Device Pin/Packages Price Single Family SupplyDual Family Quad FamilyMultipoint-LVDS M-LVDS Lvds FeaturesMultipoint Lvds Lvds Devices from TIPart-to HalfKey Features Mbps Jitter To ensure signal integrityDigital Isolators Digital Isolators Selection GuideRS-485/422 Family of Products RS-485/422No. Dr/Rx FeaturesNodes SoicRS-232 Flexible power-saving options enable longer battery lifeRS232 IEC6100-4-2 Level ESD-Protected Devices Space-saving QFN package options for portable applicationsDrivers Receivers DevicePin/Packages Price Pin/Package Price RS-232 Selection GuideUARTs Universal Asynchronous Receiver/Transmitters Programmable sleep mode and low-power modeUart Family of Products 64-byte FIFOs available 3-, 2.5- and 1.8-V supplyUart Selection Guide UARTs Universal Asynchronous Receiver/TransmittersAsynchronous Communications Element with Autoflow Control PDAs MP3 players Gaming systems Modems Serial ports TelecomCan Transceiver Selection Guide Can 3.3-V and 5-V High-Speed can TransceiversSelection Guide Standard Compliant ProtocolsFlatLinkTM 3G Display SerDes for Mobile Phones Flatlink 3GFlatLink 3G Selection Guide 1755SerDes Serial Gigabit Transceivers and Lvds SerDes Solutions-Frontplane/BackplaneBuffer PhotoGigabit Ethernet/FibreChannel SerDes Serial Gigabit Transceivers Selection GuideGigabit Xaui Ethernet Lvds SerdesContent protection for video sent over DVI High Bandwidth Digital Content Protection Hdcp22 DVI/PanelBus Hdcp ElementsDigital visual interface DVI compliant Desktop LCD monitors DLP and LCD projectors Digital TVsSet-top boxes Jitter Intra-Pair ps Inter-Pair Clock P-P Data P-PMax ps 40QFNSpeed Universal Serial Bus USBTransfer Type USB-to-Serial BridgeUSB Family of Products USB Hub Controllers and Peripheral DevicesPackage Port USB Hub Power Controllers USB Power Managers Family of ProductsUSB Power Managers Selection Guide Universal Serial Bus USB Power ManagersDevice PCI ExpressClassifications Key Benefits PCI ExpressTarget Markets ExpressCards PC Add-In Cards PC Motherboards Target MarketTX Block Painful and not robustRX Block Two 32-bit, 33- or 66-MHz buses PCI BridgesCapabilities FunctionalityPower Distribution Devices Family of Products CardBus Power SwitchesTransition Time Enable PredecessorIN1 to IN2 Physical-Layer Selection Issues 36 1394 FireWireLink-Layer Selection Issues OverviewReal-time streaming of audio and video 1394b AdvantagesFaster speeds from 800 Mbps to 3200 Mbps More efficient Boss arbitrationKey Features Applications FireWireConn. Conn. Conn. Conn. Conn. Conn Signal Integrity TI vs CompetitionGtlp Selection Guide Gtlp Gunning Transceiver Logic PlusDevice Description Price Other LiteratureHighlights VMEClock Distribution Circuits SN65HVD3082E SN65HVD3085ESN65HVD3088E Cross-Reference GuideSN65LVDT3486B Cross-Reference GuideSN65LVDT9637B PericomTexas Instruments Device IndexProduct Information Centers InternetImportant Notice
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