Seagate ST2000NM0063 ユーザーズマニュアル
C
ONSTELLATION
ES.1 SAS P
RODUCT
M
ANUAL
, R
EV
. G
57
11.4.6
SAS transmitters and receivers
A typical SAS differential copper transmitter and receiver pair is shown in Figure 19. The receiver is AC coupling to eliminate ground shift
noise.
noise.
Figure 19.
SAS transmitters and receivers
11.4.7
Power
The drive receives power (+5 volts and +12 volts) through the SAS device connector.
Three +12 volt pins provide power to the drive, 2 short and 1 long. The current return for the +12 volt power supply is through the common
ground pins. The supply current and return current must be distributed as evenly as possible among the pins.
ground pins. The supply current and return current must be distributed as evenly as possible among the pins.
Three +5 volt pins provide power to the drive, 2 short and 1 long. The current return for the +5 volt power supply is through the common
ground pins. The supply current and return current must be distributed as evenly as possible among the pins.
ground pins. The supply current and return current must be distributed as evenly as possible among the pins.
Current to the drive through the long power pins may be limited by the system to reduce inrush current to the drive during hot plugging.
11.5
S
IGNAL CHARACTERISTICS
This section describes the electrical signal characteristics of the drive’s input and output signals. See Table 15 for signal type and signal
name information.
name information.
11.5.1
Ready LED Out
Table 16 Ready LED Out conditions
N
ORMAL COMMAND ACTIVITY
LED
STATUS
Ready LED Meaning bit mode page 19h
0
1
Spun down and no activity
Off
Off
Spun down and activity (command executing)
On
On
Spun up and no activity
On
Off
Spun up and activity (command executing)
Off
On
Spinning up or down
Blinks steadily
(50% on and 50% off, 0.5 seconds on and off for 0.5 seconds)
Format in progress, each cylinder change
Toggles on/off
l
1
1
1
1
X
X