Seagate ST3300457FC, ST3300557FC FC-AL transmitters and receivers, Pin Signal name Signal type

Table 24: FC-SCA pin descriptions

Pin	Signal name	Signal type
1*	-EN bypass port A	Low Voltage TTL output
2*	12 Volts
3*	12 Volts
4*	12 Volts
5*	-Parallel ESI
6*	Ground[1]
7*	Active LED out	Open collector out
8*	Reserved
9*	Start_1[2]	TTL input
10*	Start_2[2]	TTL input
11*	-EN bypass port B	Low Voltage TTL output
12*	SEL_6	TTL input/output
13*	SEL_5	TTL input/output
14*	SEL_4	TTL input
15*	SEL_3	TTL input/output
16*	Fault LED out	Open collector out
17*	DEV_CTRL_CODE_2[2]	TTL input
18*	DEV_CTRL_CODE_1[2]	TTL input
19*	5 Volts
20*	5 Volts

Pin	Signal name	Signal type
21	12 Volts charge
22	Ground
23	Ground
24*	+Port A_in	FC Diff. input pair
25*	-Port A_in
26	Ground
27*	+Port B_in	FC Diff. input pair
28*	-Port B_in
29	Ground
30*	+Port A_out	FC Diff. output pair
31*	-Port A_out
32	Ground
33*	+Port B_out	FC Diff. output pair
34*	-Port B_out
35	Ground
36	SEL_2	TTL input/output
37	SEL_1	TTL input/output
38	SEL_0	TTL input/output
39	DEV_CTRL_CODE_0[2	TTL input
40	5 Volts charge

*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.

12.5.5FC-AL transmitters and receivers

A typical FC-AL differential copper transmitter and receiver pair is shown in Figure 15. The receiver is required to provide the AC coupling to eliminate ground shift noise.

TX

Transmitter 100

TY

.01

Differential

Transfer Medium

.01

RX

Receiver 100

RY

Figure 15. FC-AL transmitters and receivers

Cheetah 15K.7 FC Product Manual, Rev. C 67