Chapter 3 Hardware
24 Reference Manual XTX 820
Universal Serial Bus (USB)
The XTX 820 COM supports up to six USB ports on the baseboard and the supported features are listed
below.
• USB v2.0 backward compatible to legacy v.1.1
• Two root hubs and 4 ports on J1
• Two ports and 1 root hub on J2
• Supports USB boot of floppy disk drives, hard disk drives, CD-ROMs, or other USB boot devices
• Integrated physical layer transceivers
• Over-current detection status on USB ports 1 and 2
Table 3-5. Simplified USB Interface Pin/Signal Descriptions (J1)
J1
Pin #
Signal Description
USBP USB Power –
76 USB0- Universal Serial Bus Port 0 Data Negative Polarity
88 USB0+ Universal Serial Bus Port 0 Data Positive Polarity
80 USB1- Universal Serial Bus Port 1 Data Negative Polarity
92 USB1+ Universal Serial Bus Port 1 Data Positive Polarity
58 USB2- Universal Serial Bus Port 2 Data Negative Polarity
66 USB2+ Universal Serial Bus Port 2 Data Positive Polarity
62 USB3- Universal Serial Bus Port 3 Data Negative Polarity
72 USB3+ Universal Serial Bus Port 3 Data Positive Polarity
GND USB Port ground
Note: The shaded area denotes power or ground.
Serial Interrupt Request
This SERIRQ signal is connected to serial request input on the I/O Hub (Southbridge) chip (82801FBM)
for the alternative LPC/PCI interrupts. If this feature is supported, then DMA2 (DAck2 and DRQ2)
shall not be supported by XTX 820 module.
Table 3-6. Simplified Serial Interrupt Request (J1)
J1 Pin # Signal Description
21 SERIRQ Serial Interrupt Request – This pin is used to support the serial interrupt protocol.
AC’97 Sound
The XTX 820 module supports the AC’97 audio standard and the supported features are listed below.
• Provides Realtek ALC 655, AC'97/HDA (High Definition Audio CODECs)
• AC’97 Rev 2.2 compliant
• Supports audio amplifier on baseboard
• PC-Beep passthrough to Line Out while reset is held active low
• True Line Level Output with volume control independent of Line Out
• Digital 3V and 5V compliant
