Ampro Corporation XTX 820 Benutzerhandbuch
Chapter 3
Hardware
50
Reference Manual
XTX 820
Real Time Clock (RTC)/Battery
The XTX 820 supports a Real Time Clock (RTC) and CMOS RAM for the BIOS Setup Utility. The
RTC and 256 byte of CMOS RAM are included inside the I/O Hub (Southbridge) chip (82801FBM).
The RTC and CMOS are powered through pin-8 (BAT) on J4 with a Lithium Battery located on the
baseboard. If the battery is not present, the BIOS has a battery-free boot option to complete the boot
process. .
RTC and 256 byte of CMOS RAM are included inside the I/O Hub (Southbridge) chip (82801FBM).
The RTC and CMOS are powered through pin-8 (BAT) on J4 with a Lithium Battery located on the
baseboard. If the battery is not present, the BIOS has a battery-free boot option to complete the boot
process. .
Table 3-26. Simplified Power Control and Miscellaneous Pin/Signal Descriptions (J4)
J4
Pin #
Pin #
Signal
Description
3
5V_SB
5 volt Suspend – This control signal is sent to the ATX power supply for a
suspend or standby state.
suspend or standby state.
4
PWGIN
Power Good In – This active high input signal indicates to the XTX 820, the
power is good and it can begin the boot process.
power is good and it can begin the boot process.
5
PS_ON
Power Supply On – This active-low output signal from the XTX 820 is sent
to the ATX power supply to turn it on.
to the ATX power supply to turn it on.
7
PWRBTN*
Power Button – This signal provides a ground temporarily through an open
collector driver to the ATX power supply to change states (turn it on).
collector driver to the ATX power supply to change states (turn it on).
6
SPEAKER
Speaker – This PC speaker output signal must be connected to a speaker
(piezoelectric or dynamic) on the baseboard to hear the output (beeps).
(piezoelectric or dynamic) on the baseboard to hear the output (beeps).
11
RSMRST*
Resume Reset – This signal is driven low by external circuitry to reset the
power management logic on the XTX 820.
power management logic on the XTX 820.
19
OVCR
Over Current Detect – This signal indicates a USB over-current condition.
8
BAT
Battery Voltage – This is the + battery connection to baseboard for +3 volt
lithium backup battery used for RTC operation and CMOS non-volatile
memory.
lithium backup battery used for RTC operation and CMOS non-volatile
memory.
41
BATLOW*
Battery Low – This external signal to the XTX 820 indicates when the
external battery is low.
external battery is low.
21
EXTSMI*
Extern System Management Interrupt – This signal is provided by external
circuitry to initiate an SMI event with the XTX 820.
circuitry to initiate an SMI event with the XTX 820.
23
SMBCLK
System Management Bus Clock – This signal is used to support internal and
external SMBus devices, such as temperature and battery monitoring.
external SMBus devices, such as temperature and battery monitoring.
24
SMBDATA
System Management Bus Data – This signal is used to support internal and
external SMBus devices, such as temperature and battery monitoring.
external SMBus devices, such as temperature and battery monitoring.
26
SMBALRT*
System Management Bus Alert – This signal is used by SMBus devices to
signal an event on the SM Bus.
signal an event on the SM Bus.
Note: The shaded area denotes power or ground.
SMBus (I
2
C Bus)
The I/O Hub (82801FBM) contains an integrated SMBus controller with both a host and slave SMBus
port; but the host cannot access the slave internally. The slave port allows an external master access to
the I/O Hub (Southbridge) through the J4 connector. The master contained in the I/O Hub is used to
communicate with the Memory & Graphics Hub, DDR2 RAM EPROM, and the clock generator.
port; but the host cannot access the slave internally. The slave port allows an external master access to
the I/O Hub (Southbridge) through the J4 connector. The master contained in the I/O Hub is used to
communicate with the Memory & Graphics Hub, DDR2 RAM EPROM, and the clock generator.
• The I
2
C slave address must not be the same as the I
2
C device on the baseboard.