Abstract: A scheme based on FIFO circular buffering to schedule DSP peripheral devices in real-time systems is presented.The circular buffer schedulablity requires the ratio of the total response time of the peripheral device to total time is less than 1,which is the sufficient and necessary condition.An off-line numerical method is proposed to calculate the minimal space of the buffer in the case of data frames inputting periodically into peripheral devices.Furthermore,the scheme can quickly calculate the minimal space of the circular buffer when it is applied to a certain navigation receiver design.