DATOptic ARC-1680 Series - Manual (Page 38)

HARDWARE INSTALLATION
38
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)
SideBand6 Reserved SideBand7 Reserved
C: 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 efficient LED management and for
sensing drive locate status. See SFF 8485 for the specification 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 SAS RAID controller, could control the LEDs. Activity: blink-
ing/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 defines the SGPIO assignments for the Min
SAS 4i connector (SFF-8087) i n SAS RAID controller.