| 摘要 |
A system and method is provided for arbitrating ownership of a PCI bus among multiple connected devices. In particular, the present system and method provides for a continual shift of device priorities depending on how that device makes use of the bus (how often and for how long). This arbiter design differs from a conventional arbiter implementation in that it is very flexible allowing the behavior to be tailored to the requirements of the system as a whole. The arbitration methodology includes setting initial maximum and minimum priority values for each connected device. When a device is granted bus ownership, its maximum priority value is decremented by one, thereby changing its priority in relation to other devices which may request bus ownership. When the devices maximum priority value falls below that of another device requesting ownership, the first device must release bus ownership to the second device. By providing programmable priorities for each device, a ranking of the devices on the bus can be established that can change as conditions require.
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