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Chapter 3
Table 3-9.
Utility 2 Interface Pin Signals (J13) (Continued)
10
MCLK
11
GND
12
VCC
13
SMBCLK
14
SMBDATA
15
NC
16
NC
17
NC
18
NC
19
NC
20
NC
21
NC
22
NC
23
NC
24
NC
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
32
I/O
Mouse Clock– Clock signal provided to external mouse connector
-
Ground
-
+5 Volts
I/O
SMBus Clock – Clock signal provided to external devices.
I/O
SMBus Data – Data signal provided to external devices.
-
Not connected (+5V USB Port Power)
-
Not connected (+5V USB Port Power)
-
Not connected (USB 0 Negative Data Signal)
-
Not connected (USB 1 Negative Data Signal)
-
Not connected (USB 0 Positive Data Signal)
-
Not connected (USB 1 Positive Data Signal)
-
Not connected (USB Port ground)
-
Not connected (USB Port ground)
-
Not connected [USB Port shield (Cable Shield)]
-
Not connected [USB Port shield (Cable Shield)]
Reference Manual
Hardware
LittleBoard 735
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