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Chapter 4: Motherboard Connections
4.2 Power Connections
Two power connections supply the motherboard and several more supply for onboard devices.
Main Power Connector
The 24-pin power supply connector (JPWR3) meets the ATX SSI EPS 12V specification. You
must also connect the 8-pin (JPWR1) and 4-pin (JPWR2) processor power connector to the
power supply.
Important:
To provide adequate power to the motherboard, connect both the main power
connector and 8-pin/4-pin power connectors to the power supply. Failure to do so may void
the manufacturer's warranty on your power supply and motherboard.
8-pin Power
Pin Definitions
Pin#
Definition
1 - 4 Ground
5 - 8 +12 Vdc
4-pin Power
Pin Definitions
Pin#
Definition
1 - 2 Ground
3 - 4 +12Vdc
4.3 Headers and Connectors
Fan Headers
There are seven fan headers (FAN1-FAN5, FANA, FANB) on the motherboard. These are
4-pin fan headers, although pins 1-3 are backward compatible with traditional 3-pin fans.
Four-pin fans allow fan speeds to be controlled by Thermal Management in the BMC. When
using the Thermal Management setting, use all 3-pin fans or all 4-pin fans.
Fan Header
Pin Definitions
Pin#
Definition
1
Ground (Black)
2
+12V (Red)
3
Tachometer
4
PWM Control
SGPIO Header
A Serial General Purpose Input/Output header (S-SGPIO1) is used to communicate with the
enclosure management chip on the backplane.
SGPIO Header
Pin Definitions
Pin#
Definition
Pin#
Definition
1
NC
2
NC
3
Ground
4
DATA Out
5
Load
6
Ground
7
Clock
8
NC
NC = No Connection