Oki JOB60851 User Manual

Contents

Oki JOB60851 User Manual Manual pdf 41 page image

Chapter 4 Software Developmentpage 4-64-1-8. Data RatesThe USB supports two data rates: 12 Mb/s and 1.5 Mb/s. Table 4.1.4 lists the maximum payloadsizes for each combination of data flow type and data rate.Table 4.1.4. Maximum Payload SizesMAX Payload SizeTransfer Types 12 Mbps 1.5 MbpsControl 8/16/32/64 8Isochronous 1023 or less N/AInterrupt 64 or less 8 or lessBulk 8/16/32/64 N/AA hub determines the data rates supported by an attached function by examining the latter's NonReturn to Zero Invert (NRZI) data signal lines (D+ and D-). A device supporting the high speedpulls up the D+ line to the 3.3-volt power supply voltage with a 1.5-kΩ resistor; one supporting thelow speed does the same with the D- line.The ML60851C USB controller operates exclusively at 12 Mb/s, so the JOB60851 board includesonly the D+ pull-up resistor.4-1-9. Device Class SpecificationsThe Universal Serial Bus Device Class Specifications complement the core specifications by furtherstandardizing USB devices for major interfaces and specific applications devices using thoseinterfaces.Some interface specifications standardize the communications pathways that the USB hardwareprovides for a specific purpose--the exchange of isochronous audio or image data, for example.Others standardize USB specifications for devices combining multiple interfaces.Table 4.1.5 lists some of the USB Device Class Specifications currently available. For further details,refer to the following URL.Table 4.1.5. USB Device Class SpecificationsDevice Class Applicable EquipmentHuman interface devices (HIDs) Mice, keyboards, joysticks, etc.Printers PrintersAudio devices Speakers, microphones, etc.Communications devices Modems, ISDN terminal adapters, etc.Mass storage devices Fl oppy disk drives, SCSI equipment, ATAPI equipment, etc.Image devices Digital cameras, scanners, low-rate video, etc.There is also a standard for downloading programs to devices.http://www.usb.org/developers/devclass.html