Cheetah 15K.5 FC Product Manual, Rev. F
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9.5.12 Device control codes
The drive inputs a Device Control Code on the DEV_CTRL_CODE lines at power up to determine the link rate
on the Fibre Channel ports. Both ports run at the same rate. If the backpanel does not connect to these lines,
the drive has 10K ohm pull up resistors that default the device control code to 7 (1.0625 GHz). Table lists the
supported codes.
9.6 Signal characteris tics
This section describes the electrical signal characteristics of the drive’s input and output signals. See Table 23
on page 66 for signal type and signal name information.
9.6.1 TTL input characteristics
Table 28 provides the TTL characteristics.
Table 27: Device control code values
2 (pin 17) 1 (pin 18) 0 (pin 39) Definition
000Reserved for power failure warning.
001Reserved for auto negotiation of link rate.
010Reserved.
011Reserved.
100Reserved.
1014.250 GHz operation on both ports.
1102.125 GHz operation on both ports.
1111.0625 GHz operation on both ports.
Table 28: TTL characteristics
State Volta ge Current
Input high 1.9 < VIH < 5.5V IIH = ±500nA max.
Input low -0.5V < VIL < 0.9V IOL = ±500nA max.
Output high (-EN Bypass A, B) 2.4 < VOH < 5.25V IOH < -3mA
Output low (-EN Bypass A, B) VOL < 0.5V IOL < 3mA
Output high (-Parallel ESI) 2.4 < VOH < 0.9 VCC
VOH > 0.9VCC
IOH < -2.4mA
IOH < -500µA
Output low (-Parallel ESI) 0 < VOL < .45V IOL < 2.4mA
Output high (all other outputs) 2.4 < VOH < 0.9 VCC
VOH > 0.9VCC
IOH < -1.6mA
IOH < -500µA
Output low (all other outputs) 0 < VOL < .45V IOL < 1.6mA