User manual
HARDWARE INSTALLATION
37
PIN Description PIN Description
1 power (+5V) 2 GND
3 LCD Module Interrupt 4 Protective Key
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 (SFF-8087) 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) sideband signals
which use to replace the individual LED cable.
The SGPIO bus is used for efcient LED management and for
sensing 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 SATA drive
tray. A small CPLD on the backplane, connected via the SGPIO bus
to a ARC-1231ML/1261ML/1280ML SATA RAID controller, could
control the LEDs. Activity: blinking/controller access 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 blinking 2 times/second.
The following signal denes the SGPIO assignments for the Min
SAS 4i connector (SFF-8087) in ARC-1231ML/1261ML/1280ML.