Specifications

158004.B00 35
3.14 USB PORTS
The TP400 provides two USB ports. USB stands for Universal Serial Bus, and is
designed to rationalise connections on PCs by providing a single port that is able to
connect to a wide range of peripherals: keyboards and mice, printers and modems,
scanners, video cameras and data acquisition systems, to name a few.
Access to the USB ports on the TP400 is through the eight-way connector J9. DSP
Design manufacture a small printed circuit board, carrying a dual USB connector and
EMC filtering components, which can be connected to the J9 connector by a short
cable assembly. The USB printed circuit board is called the TP300USB and the cable
assembly is the TP400ET-CAB. The TP300USB is designed to be mounted on an
enclosure; this location allows EMC filtering to be optimised.
The TP300USB and TB486-ET are sold as optional extras, although equivalent
circuitry exists on the TCDEVPLUS (but not on the TCDEV). See Appendix D for
ordering information.
A circuit diagram and mechanical drawing of the TP300USB are given in Appendix K.
USB keyboards can be connected to the USB ports, and can operate simultaneously
to the PS/2 keyboard. Thus up to three keyboards can be active at once.
Windows operating systems recognise the USB device (as a Compaq USB hub) and
install the correct drivers. Thereafter as Windows sees new USB devices being
plugged in (such as cameras) it will ask for the drivers for those devices to be added.
In accordance with the requirements of the USB specification, power is supplied to a
USB peripheral through a current limiting circuit. There is such a circuit on the TP400,
which limits current to about 500mA per USB channel. Some users have reported
that some USB devices do not operate correctly when directly plugged into the TP30,
but that they do when plugged in via a powered hub. This leads us to believe that
these USB peripherals may be exceeding the power output of the TP400.
By default the BIOS disables the USB ports. They should be enabled using the BIOS
Setup program. The USB control can be found in the Advanced / Advanced Chipset
Control Menu. For Windows it is only necessary to enable the "USB Host Controller"
option. The "USB BIOS Legacy Support" is only for use with USB keyboards under
MS-DOS, and should not be enabled otherwise.
The USB controller is treated as a PCI device. It is PCI slot 1 (see section 4.3). It is
allocated an interrupt, often IRQ11, by the BIOS’s Plug and Play software (see
section 4.5 for details).
3.15 ETHERNET
The TP400 includes a 10/100Base-T Ethernet controller chip. This allows the TP400
to form part of a Local Area Network (LAN).
The chip is the National Semiconductor DP83815, and it is connected to the on-board
PCI bus as the slot 4 device (see 4.3). The chip is configured by the Plug and Play