| 摘要 |
One aspect of the present invention provides a packer-unpacker (PUP) for a digital serial interface which allows a plurality of processors to access time slot registers of a serial data stream relating to the digital serial interface. A configuration register is maintained either by one of the plurality of processors or by each of the processors to arbitrate access to the individual time slot registers. Another aspect of the invention allows one or more processors to efficiently access and/or write more bits to a resource such as a time slot register than the width of the processor's respective data bus allows. Extra bits registers are maintained for at least one of the read and write direction data busses. The extra bits correspond to the least significant bits conventionally ignored in changing from a data bus of one width to a data bus of a narrower width. The extra bits in the write direction are accessed, e.g., by a write to a write direction extra bits register addressable through a specific input/output (I/O) location. The extra bits are tacked on to a subsequent write cycle in the digital serial interface, e.g., in the AC '97 link, to write an excess length data word. In the read direction, each read cycle places excess bits in a read direction extra bits register for reading in a subsequent read cycle. Another aspect of the invention provides an automatic status register which provides, e.g., automatic creation of a TAG Phase in time slot 0 of an AC '97 link using, e.g., a write enable signal to various resources in the digital serial interface, e.g., write enable signals to time slot registers.
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