Host selectively determines whether a task should be performed by digital signal processor or DMA controller according to processing time and I/O data period

摘要

A low-cost digital signal processing system is provided which can prevent data loss during data transfer and can eliminate processing overhead regardless of the length of the I/O period of an external I/O processing device. When the data I/O period of the external I/O device such as an A/D converter is shorter than the period of data processing by the DSP, the data reception and transmission are performed through a DMA controller between the external I/O devices and the memory to reduce the burden on the DSP. On the other hand, when the data input and output period is longer than the DSP processing time, the data reception and transmission is directly carried out by the external I/O device and the DSP without use of the DMA controller. In addition, in the execution of a DSP program which comprises at least one process, a function of each process is provided to have input and output parameters identifying the addresses of data reception or transmission units which are assigned to the input and output parameters to simplify the DSP programming.