OCPRF100 MP Server System Technical Product Specification

Revision 1.0

²Spin-down of a drive when failure is detected and reported (using enclosure services messages) via the SCSI bus. An application or RAID controller detects a drive-related problem that indicates a data risk. In response, it takes the drive out of service and sends a spin down SCSI command to the drive. This decreases the likelihood that the drive is damaged during removal from the hot-swap drive bay. When a new drive is inserted, the power control waits a small amount of time for the drive to be fully seated, and then appiles power to the drive to prepare for operation.

²If system power is on, the backplane immediately powers off a drive slot when it detects a drive has been removed. This prevents possible damage to the drive when it is partially removed and reinserted while full power is available. It also prevents disruption of the entire SCSI array due to possible sags in supply voltage and resultant current spikes.

8.2.5FET Short Protection

The FET short protection circuit is useful to protect both 12 volt and 5 volt power control FETs located on the backplane.

8.2.6Microcontroller

The microcontroller provides all the intelligence for the LVDS SCSI backplane. It is an 80C652

microcontroller, with a built-in I2C interface. The 80C652 microcontroller uses Flash for program code storage, and static RAM for program variables and buffers.

8.2.7LED Arrangement

The three LEDs per drive are arranged as follows (viewed from the drive bay):

Green

Green

Yellow

Power

Activity

Fault

LED

LED

LED

Figure 8-3: LED Arrangement

8.2.7.1Power LEDs

Power LEDs are green and they indicate the drive is receiving power. Power LED control is driven by the FET switched +5 volts applied to the drive.

8.2.7.2Drive Activity LEDs

The activity LEDs are green and are driven by the drive, pin 77, and interfaces directly to the LED.

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