Chapter 3
Hardware
LittleBoard 735
Reference Manual
29
USB Interfaces
The I/O Hub (82801GBM) provides the USB solution for both legacy UHCI controller and EHCI controller
(USB 2.0) support. The I/O Hub (Southbridge) contains port-routing logic that determines which controller
(UHCI or EHCI) handles the USB data signals. The J44 header provides two of the six USB ports: USB0
and USB1. The J14 header provides USB2 and USB3, and the J39 header provides USB4 and USB5.
USB 2.0 Support
The I/O Hub (Southbridge) contains an Enhanced Host Controller Interface (EHCI) compliant host
controller, which supports up to six high-speed USB 2.0 Specification compliant root ports. The higher
speed USB 2.0 specification allows data transfers up to 480 Mbps using the same pins as the six full-speed/
low-speed USB UHCI ports. The I/O Hub (Southbridge) port-routing logic determines which of the
controllers (UHCI or the EHCI) processes the USB signals.The USB 2.0 features implemented in the USB
ports include the following:
•
One EHCI host controller for all six USB ports
•
Supports USB V2.0 Specification
Legacy USB Support
The I/O Hub (Southbridge) supports three USB Universal Host Controller Interfaces (UHCI) and each Host
Controller includes a root hub with two separate USB ports each, for a total of six USB ports. The USB
Legacy features implemented in the USB ports include the following:
•
Three root hubs for six USB ports
•
Support for USB v1.1 and UHCI v1.1 with integrated physical layer transceivers
•
Improved arbitration latency for UHCI controllers
•
UHCI controllers support Analog Front End (AFE) embedded cell instead of USB I/O buffers to allow
for USB high-speed signaling rates
•
Three shared over-current fuses, located on the board, are used on all six USB ports
USB0 and USB1
Table 3-10
lists the USB0 and USB1 pin signals which use 10 pins, 2 rows, odd/even sequence (1, 2) with
0.079" (2mm) pitch.
CAUTION
ADLINK does not recommend connecting a USB boot device to the
LittleBoard 735 through an external hub. Instead, connect the USB boot
device directly to the LittleBoard 735.
Table 3-10. USB 0 & 1 Interface Pin Signals (J44)
Pin #
Signal
Description
1
USBPWR0
+5 volts power, USB 0
2
USBPWR1
+5 volts power, USB 1
3
USB0-
USB 0 Data Negative
4
USB1-
USB 1 Data Negative
5
USB0+
USB 0 Data Positive
6
USB1+
USB 1 Data Positive
7
USB GND0
USB 0 Ground
8
USB GND1
USB 1 Ground
Содержание LittleBoard 735
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Страница 50: ...Chapter 4 BIOS Setup 44 Reference Manual LittleBoard 735 ...
Страница 52: ...Appendix A Technical Support 46 Reference Manual LittleBoard 735 ...