초록 ▼

In the context of a bus-mastering system, a device selector selects the device to control the bus by assigning "combined" priority values to the devices and selecting the device with the highest combined-priority value. The combined-priority values include relatively high-significance device-specifi

In the context of a bus-mastering system, a device selector selects the device to control the bus by assigning "combined" priority values to the devices and selecting the device with the highest combined-priority value. The combined-priority values include relatively high-significance device-specific values and relatively low-significance arbitrary-rank values. At any given time, no two devices share the same arbitrary-rank values, and thus cannot share combined-priority values. Thus, there are no unresolved selections due to equal priorities. In accordance with the present invention, the arbitrary-rank values are varied in a round-robin fashion to minimize the bias inherent in conventional schemes using a priority encoder. This makes the device selection process conform better to the device-specific values, which are presumable selected to optimize system performance. Accordingly, the inventive use of variable arbitrary-rank values in the device selector enhances the performance of the incorporating system.

대표청구항 ▼

1. A device selector for selecting at a given time one device of a set of at least two devices, said selector comprising:input means for receiving device-specific data units, each of said device-specific data units being associated with exactly one of said devices; priority assignment means for assi

1. A device selector for selecting at a given time one device of a set of at least two devices, said selector comprising:input means for receiving device-specific data units, each of said device-specific data units being associated with exactly one of said devices; priority assignment means for assigning priority values respectively to said devices, said priority values including relatively more-significant device-specific values and relatively less-significant arbitrary-ranking values, each of said priority values including a respective one of said device-specific values and a respective one of said arbitrary-ranking values, said priority assignment means assigning each device-specific value as a function of device-specific data units associated with the respective device, said priority assignment means assigning said arbitrary-ranking values so that no two of said devices have the same arbitrary-ranking value at the same time, the arbitrary-ranking values associated with said devices at any given time determining an arbitrary ranking among said devices; selection means for selecting at any given time one of said devices as a function of said priority values; and rank varying means for changing said arbitrary-ranking values so as to change the arbitrary ranking of said devices.