| 摘要 |
A CPCI system is adapted to reliably detect the presence of all front cards, whether hot swappable or not. The system includes a line that is used to detect the presence of a front card. The line is connected to a connector-pin of a slot. The line is also connected to a pull-up resistor so that when a front card is not inserted in the slot, the line has a high value. When a front card is inserted in the slot, the connector-pin mates with a corresponding connector-pin in the front card. The corresponding connector-pin is connected to a ground layer of the front card so that the line becomes grounded. The voltage level on the line is input to a register that outputs a high or low to a circuit for detecting the presence of a front card. The circuit may be a hot swap controller, a CPU or a status indicator. Accordingly, depending on the output of the register, the circuit reliably determines whether a front card is present in the particular slot. The reliable detection of all front cards provides to the operating system of the CPU a more accurate view of the hardware configuration.
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