ADLINK LittleBoard 735 - Manual (Page 38)

Chapter 3 Hardware
32 Reference Manual LittleBoard 735
Note: The shaded table cells denote power or ground. The * symbol indicates the signal is Active Low.
USB Interfaces
The I/O Hub (82801GBM) provides the USB solution for both legacy UHCI controller (USB 1.1) 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
10 MCLK I/O Mouse Clock– Clock signal provided to external mouse connector
11 GND - Ground
12 VCC - +5 Volts
13 SMBCLK I/O SMBus Clock – Clock signal provided to external devices.
14 SMBDATA I/O SMBus Data – Data signal provided to external devices.
15 NC - Not connected (+5V USB Port Power)
16 NC - Not connected (+5V USB Port Power)
17 NC - Not connected (USB 0 Negative Data Signal)
18 NC - Not connected (USB 1 Negative Data Signal)
19 NC - Not connected (USB 0 Positive Data Signal)
20 NC - Not connected (USB 1 Positive Data Signal)
21 NC - Not connected (USB Port ground)
22 NC - Not connected (USB Port ground)
23 NC - Not connected [USB Port shield (Cable Shield)]
24 NC - Not connected [USB Port shield (Cable Shield)]
Table 3-9. Utility 2 Interface Pin Signals (J13) (Continued)