Seagate Cheetah 73LP FC ST336605FC, Product Manual

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52 Cheetah 73LP FC Product Manual, Rev. D
9.5.3 Electrical description
Fibre Channel drives use the FC-SCA connector for:
• DC power
• FC-AL interface
• Drive select (device identification)
• Option selection
• Enclosure Services interface
This 40-pin connector is designed to plug directly into a backpanel. External cables are not required.
9.5.4 Pin descriptions
This section provides a pin-out of the FC-SCA and a description of the functions provided by the pins.
Table 19: FC-SCA pin descriptions
*Short pins in mating backpanel connector.
[1] This pin may be connected to external logic to detect the presence of the drive. The drive connects this
pin to the common ground.
[2] Pins 9, 10, 17, 18, and 39 are option select pins and are tied high by the drive circuitry. The preferred elec-
trical connection at the backplane is either open or grounded (open for the ‘1’ setting, grounded for the ‘0’
setting). Alternatively, these pins may be driven by a 3.3V logic device, pulled up to 3.3V through a pull-up
resistor (recommended size of 10K ohm), or grounded through some other means.
Pin Signal name Signal type Pin Signal name Signal type
1* -EN bypass port A Low Voltage
TTL output 21 12 Volts charge
2* 12 Volts 22 Ground
3* 12 Volts 23 Ground
4* 12 Volts 24* +Port A_in Diff. PECL input pair
5* -Parallel ESI 25* -Port A_in
6* Ground
[1]
26 Ground
7* Active LED out Open collector out 27* +Port B_in Diff. PECL input pair
8* Reserved 28* -Port B_in
9* Start_1 [2] TTL input 29 Ground
10* Start_2 [2] TTL input 30* +Port A_out Diff PECL output pair
11* -EN bypass port B Low Voltage
TTL output 31* -Port A_out
12* SEL_6 TTL input/output 32 Ground
13* SEL_5 TTL input/output 33* +Port B_out Diff PECL output pair
14* SEL_4 TTL input 34* -Port B_out
15* SEL_3 TTL input/output 35 Ground
16* Fault LED out Open collector out 36 SEL_2 TTL input/output
17* DEV_CTRL_CODE_2
[2] TTL input 37 SEL_1 TTL input/output
18* DEV_CTRL_CODE_1
[2] TTL input 38 SEL_0 TTL input/output
19* 5 Volts 39 DEV_CTRL_CODE_0 [2] TTL input
20* 5 Volts 40 5 Volts charge