| 摘要 |
An improved audio-output device coupleable to a computer system, in which a DSP operating under software control emulates a common command interface. The command interface has a set of registers that are made available to the CPU for reading and writing, even if there are no such physical registers available in the device. The DSP also performs tasks in addition to audio-output, even though the audio-output device is required to respond immediately to commands from the CPU. The audio-output device has a DSP for interpreting and executing commands received from the CPU, a local memory for storing data input to or output from the DSP, a bus-interface (BIF) element for coupling the DSP and memory to a system bus, and a direct memory access (DMA) element for transferring data between the local memory and the system bus. The local memory has an emulation region for emulating a set of named registers the CPU may read from and write into according to the command interface, and a communication region for transmitting messages between the CPU and the DSP. The emulation region is indicated by a base register and a set of offset values, and has a dynamically allocated set of registers for emulating the set of named registers the CPU may read from and write into. |
