HARDWARE INSTALLATION
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PIN Description PIN Description
1 power (+5V) 2 GND
3 LCD Module Interrupt 4 Fault/Activity Interrupt
5 LCD Module Serial Data 6 Fault/Activity clock
7 Fault/Activity Serial Data 8 LCD Module clock
D: SGPIO bus
The preferred I/O connector for server backplanes is the Min SAS
4i internal serial-attachment connector. This connector has eight
signal pins to support four SATA drives and six pins for the SGPIO
(Serial General Purpose Input/Output) side-band signals. The
SGPIO bus is used for efcient LED management and for sens-
ing drive Locate status. See SFF 8485 for the specication of the
SGPIO bus.
The number of drives supported can be increased, by a factor of
four, by adding similar backplane to maximum of 24 drives (6
backplanes)
LED Management: The backplane may contain LEDs to indicate
drive status. Light from the LEDs could be transmitted to the out-
side of the server by using light pipes mounted on the SAS drive
tray. A small EPLP microcontroller on the backplane, connected via
the SGPIO bus to a ARC-1231ML/1261ML/1280ML SATA RAID con-
troller, could control the LEDs. Activity: blinking 5 Times/Second
Fault: solid illuminated
Drive Locate Circuitry: The locate of a drive may be detected by
sensing the voltage level of one of the pre-charge pins before and
after a drive is installed. Fault (red) blinking 2 Times/Second.
The following signal denes the SGPIO assignments for the Min
SAS 4i connector in ARC-1231ML/1261ML/1280ML.
PIN Description PIN Description
SideBand0 SClock (Clock Signal) SideBand1 SLoad (Last clock of a bit
stream)
SideBand2 Ground SideBand3 Ground
SideBand4 SDataOut (Serial data
output bit stream)
SideBand5 SDataIn (Serial data input bit
stream)