ADLINK Technology LitleBoard 800 Reference Manual

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ADLINK Technology LitleBoard 800 Reference Manual Manual pdf 34 page image

Chapter 3 Hardware28 Reference Manual LittleBoard 800System Management Bus (SMBus)The I/O Hub, 82801DB, (Southbridge) contains both a host and slave SMBus port; but the host cannotaccess the slave internally. The slave port allows an external master access to the I/O Hub through theconnector (J13). The master contained in the 82801DB is used to communicate with the SDRAM DDRDIMM, 82541(GI/PI) Gigabit Ethernet controller, and the clock generator. Table 3-8 gives the addresses forthese devices with the components and corresponding binary addresses of the SMBus.USB Signals (USB1 and USB2)The LittleBoard 800 contains two root USB hubs with four functional USB ports. This connector(Utility 2) provides two of the four USB ports (USB0 and USB1). The hub is USB EHCI V2.0 and UHCIV1.1 compatible.Features implemented in the USB ports include the following:• Support for USB EHCI v2.0 and UHCI v1.1• Integrated physical layer transceivers• Over-current detection status (software) on all four USB portsMouse InterfaceThe signal lines for a PS/2 mouse are provided through the Utility 2 interface (J13).Infrared Port (IrDA)The Infrared Data Association (IrDA) port provides a two-way wireless communications port using infraredas a transmission medium at the basic level. There are two basic infrared implementations provided; theHewlett-Packard Serial Infrared (HPSIR) and the Amplitude Shift Keyed Infrared (ASKIR) methods.HPSIR is a serial implementation of infrared developed by Hewlett-Packard. The IrDA (HPSIR andASKIR) signals are available on the Utility 2 connector.The HPSIR method allows serial communication at baud rates up to 115k baud. Each word is sent seriallybeginning with a zero value start bit. A zero is sent when a single infrared pulse is sent at the beginning ofthe serial bit time. A one is sent when no infrared pulse is sent during the bit time.The Amplitude Shift Keyed infrared (ASKIR) allows serial communication at baud rates up to 19.2k baud.Each word is sent serially beginning with a zero value start bit. A zero is sent when a 500kHz waveform issent for the duration of the serial bit time. A one is sent when no transmission is sent during the serial bittime.Both of these methods require an understanding of the timing diagrams provided in the Super I/O-1controller chip (LPC47B272) specifications available from the manufacture’s web site and referred to earlierin this manual. For more information, refer to the SMSC LPC47B272 chip databook and the Infrared DataAssociation web site at http://www.irda.org.Table 3-8. SMBus Reserved AddressesComponent Address BinarySDRAM EPROM 1010,000x bClock Generator (ICS950811) 1101,001x bI/O Hub (82801DB) 0000,000x b (default) Programmable MasterCAUTION ADLINK does not recommend connecting a USB boot device to theLittleBoard 800 through an external hub. Instead, connect the USB bootdevice directly to the LittleBoard 800.NOTE For faster speeds and infrared applications not covered in this brief description,refer to the LPC47B272 chip specifications by Standard Microsystems Corp.