Areca ARC-1120, ARC-1110, ARC-1130, ARC-1231ML/1261ML/1280ML manual Pin

HARDWARE INSTALLATION

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 efficient LED management and for sens- ing 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 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 defines 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	SideBand5	SDataIn (Serial data input bit
	output bit stream)		stream)

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