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USB 2.0 Data Logging Application

Anthony Drake
Prodigy 140 points

I'm in the process of planning a design to record USB transactions to flash, in a low power, small form fit system using MSP43055XX µcontroller.

I'm new to USB, if anyone can suggest a USB primer, that would be helpful.

Also helpful would be ideas of how to interface the abovementioned processor to flash memory, the SPI and parallel GPIO come to mind, I see no external memory interface or programmable glue logic in the data sheet.

Thanks in advance.

  • 0
    Genius 4680 points

    > USB 2.0 Data Logging Application
    > a design to record USB transactions to flash

    Elaborate more on your target project.
    Is it
    1) a USB protocol analyzer, which hooks on a USB cable
    2) a USB host, which communicates with another sensor devices
    3) a USB device, which stores data from host PC

    Tsuneo

  • 0 in reply to Tsuneo Chinzei
    Prodigy 140 points

    It would be in effect a protocol analyzer, the intended purpose is to monitor and record bus transactions between host and other devices on the bus.

  • 0 in reply to Anthony Drake
    Genius 4680 points

    > It would be in effect a protocol analyzer, the intended purpose is to monitor and record bus transactions between host and other devices on the bus.

    You may be interested in this article, in which hardwares and applications are compared on typical commercial USB analyzers.

    USB 2.0 Bus/Protocol Analyzer Hardware/Software Comparison
    http://www.summitsoftconsulting.com/UsbAnalyzers.htm

    These analyzers apply a USB PHY (Cypress TX2, SMSC USB3450, NXP/STEricsson) for the front-end, a FPGA for signal process and a 32M/64M SDRAM for local storage. Cypress EZUSB FX2LP connects the board to a PC.

    To deal with High-Speed (430Mbps), these combination of chips are required. If you limit the target just to Full- (12Mbps) / Low- (1.5Mbps) speed, simpler combination is possible. For example of Beagle USB 12

    Transceiver - Fairchild USB1T11AMTC
    Isolator - ADUM1400BRW
    CPLD - XC9572XL-10VQ44C
    EZ-USB FX2LP - CY7C68013A-56PVXC


    I recommend you to use a decent USB PHY or transceiver as the front-end for your bus monitor/analyzer, to receive differential D+/D- lines properly. You may think of bit-bang USB devices, like VUSB, which don't use any USB transceiver. For bit-bang USB devices, host repeats a transaction when the device fails to respond to the transaction. But for a bus monitor, host doesn't repeat the transaction, when the monitor fails to receive the transaction. Therefore, more decent front-end is required for a monitor/analyzer.


    These articles well explain on the USB signal on bus.

    USB Made Simple - Part 3 - Data Flow
    http://www.usbmadesimple.co.uk/ums_3.htm

    USB in a NutShell - USB Protocols
    http://www.beyondlogic.org/usbnutshell/usb3.shtml

    Tsuneo

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