Power Connection
JXT6966 / JXTS6966 Technical Reference
CHASSIS PLANS
3-2
CAUTION:
In some ATX/EPS systems, the power may appear to be off while the 5VSB signal is still
present and supplying power to the SHB, option cards and other system components. The +5VAUX LED
on a Chassis Plans PICMG 1.3 backplane monitors the 5VSB power signal; “green” indicates that the
5VSB signal is present. Chassis Plans backplane LEDs monitor all DC power signals, and all of the LEDs
should be off before adding or removing components. Removing boards under power may result in system
damage.
Electrical Connection Configurations
There are a number of different connector types, such as EPS, ATX or terminal blocks, which can be
utilized in wiring power supply and control functions to a PICMG 1.3 backplane. However, there are only
two basic electrical connection configurations:
ACPI Connection
and
Legacy Non-ACPI Connection.
ACPI Connection
The diagram on the previous page shows how to connect an ACPI compliant power supply to an ACPI
enabled PICMG 1.3 system. The following table shows the required connections that must be made for
soft power control to work.
Signal
Description
Source
+12
DC voltage for those systems that require it
Power Supply
+5V
DC voltage for those systems that require it
Power Supply
+3.3V
DC voltage for those systems that require it
Power Supply
+5VSB
5 Volt Standby. This DC voltage is always on when an
ATX or EPS type power supply has AC voltage
connected. 5VSB is used to keep the necessary
circuitry functioning for software power control and
wake up.
Power Supply
PWRGD
Power Good. This signal indicates that the power
supply’s voltages are stable and within tolerance.
Power Supply
PSON#
Power Supply On. This signal is used to turn on an
ATX or EPS type power supply.
SHB/Backplane
PWRBT#
Power Button. A momentary normally open switch is
connected to this signal. When pressed and released,
this signals the SHB to turn on a power supply that is
in an off state.
If the system is on, holding this button for four
seconds will cause the SHB’s chipset to shut down
the power supply. The operating system is not
involved and therefore this is not considered a clean
shutdown. Data can be lost if this situation occurs.
Power Button
