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12.5.12Device 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.
Table 28: | Device control code values |
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2 (pin 17) |
| 1 (pin 18) | 0 (pin 39) | Definition |
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0 |
| 0 | 0 | Reserved for power failure warning. |
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0 |
| 0 | 1 | Reserved for auto negotiation of link rate. |
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0 |
| 1 | 0 | Reserved. |
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0 |
| 1 | 1 | Reserved. |
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1 |
| 0 | 0 | Reserved. |
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1 |
| 0 | 1 | 4.250 GHz operation on both ports. |
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1 |
| 1 | 0 | 2.125 GHz operation on both ports. |
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1 |
| 1 | 1 | 1.0625 GHz operation on both ports. |
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12.6Signal characteristics
This section describes the electrical signal characteristics of the drive’s input and output signals. See Table 24 on page 67 for signal type and signal name information.
12.6.1TTL input characteristics Table 29 provides the TTL characteristics.
Table 29: TTL characteristics
State | Voltage | Current | |
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Input high | 1.9 | < VIH < 5.5V | IIH = ±500nA max. |
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Input low | IOL = ±500nA max. | ||
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Output high | 2.4 | < VOH < 5.25V | IOH < |
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Output low | VOL < 0.5V | IOL < 3mA | |
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Output high | 2.4 | < VOH < 0.9 VCC | IOH < |
| VOH > 0.9VCC | IOH < | |
Output low | 0 < VOL < .45V | IOL < 2.4mA | |
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Output high (all other outputs) | 2.4 | < VOH < 0.9 VCC | IOH < |
| VOH > 0.9VCC | IOH < | |
Output low (all other outputs) | 0 < VOL < .45V | IOL < 1.6mA | |
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72 | Cheetah 15K.7 FC Product Manual, Rev. C |