User manual
HARDWARE INSTALLATION
37
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
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.
The following signal denes the sideband connector which can
work with Areca sideband cable on its SFF-8087 to 4 SATA cable.
The sideband header is located at backplane. For SGPIO to
work properly, please connect Areca 8-pin sideband cable to the
sideband header as shown above. See the table for pin denitions.