Specifications

Chapter 3 Hardware
28 Reference Manual LittleBoard 800
System Management Bus (SMBus)
The I/O Hub, 82801DB, (Southbridge) contains both a host and slave SMBus port; but the host cannot
access the slave internally. The slave port allows an external master access to the I/O Hub through the
connector (J13). The master contained in the 82801DB is used to communicate with the SDRAM DDR
DIMM, 82541(GI/PI) Gigabit Ethernet controller, and the clock generator. Table 3-8 gives the addresses for
these 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 UHCI
V1.1 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 ports
Mouse Interface
The 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 infrared
as a transmission medium at the basic level. There are two basic infrared implementations provided; the
Hewlett-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 and
ASKIR) 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 serially
beginning with a zero value start bit. A zero is sent when a single infrared pulse is sent at the beginning of
the 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 is
sent for the duration of the serial bit time. A one is sent when no transmission is sent during the serial bit
time.
Both of these methods require an understanding of the timing diagrams provided in the Super I/O-1
controller chip (LPC47B272) specifications available from the manufacture’s web site and referred to earlier
in this manual. For more information, refer to the SMSC LPC47B272 chip databook and the Infrared Data
Association web site at http://www.irda.org
.
Table 3-8. SMBus Reserved Addresses
Component Address Binary
SDRAM EPROM 1010,000x
b
Clock Generator (ICS950811) 1101,001x
b
I/O Hub (82801DB) 0000,000x
b
(default) Programmable Master
CAUTION ADLINK does not recommend connecting a USB boot device to the
LittleBoard 800 through an external hub. Instead, connect the USB boot
device 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.