This application report details a mechanism by which an external slave device can directly initiate direct memory access (DMA) transfers with a TMS320C64x™ digital signal processor (DSP) without processor intervention. The mechanism utilizes the RAM-based architecture of the TMS320C64x enhanced direct memory access (EDMA) controller, static DMA transfers and DMA chaining to “effectively” allow an external slave device to dynamically program the internal EDMA controller of the DSP.

This technique can be used to implement effective, low processor overhead transfers of variable-length data between an external slave device and the internal memory of the DSP. These types of transfers often occur in wireless basestations, between an external receive chip-rate processing device and a controlling DSP. In order to implement this technique, the external slave device must have enough processing capability to generate the required fields of an EDMA transfer parameter entry.