Asynchronous multirate system design for programmable DSPs

A software design system for asynchronous multirate/multitask processing is developed for a programmable digital signal processor, the NEC77240. A new scheduling method which combines static and dynamic scheduling is proposed. This avoids runtime overheads due to interrupts in asynchronous multirate system design for digital signal processors (DSPs). The processing delay is avoided by introducing deadline scheduling in the static scheduling. In this system, a block diagram description language is extended to describe a asynchronous multitask processing. By using this scheduling method, asynchronous multirate processing such as arbitrary sampling ratio rate conversion, asynchronous interface and multimedia applications can be efficiently realized by programmable DSPs