A Cost-Efficient RISC Processor Platform for Real Time Audio Applications

A platform architecture for real time audio applications based on the open source LEON RISC processor and an audio development board based on an FPGA implementation of this platform are presented. Emphasis is on audio-specific extensions of the LEON architecture. In particular, a Floating Point Unit (FPU) for the LEON CPU and a multi-standard audio interface block were implemented. Innovative aspects, as a scoreboard based superscalar scheduler for the FPU and a new flexible approach to the interface block, unifying major parts of the required logic for all relevant interface standards are described. The extended LEON architecture is running on an Altera Stratix EP1S30-5 at more than 50 MHz. This already allows to run an mp3 decoder at up to 128 kbit/s in real-time. Porting of additional decoders as mp3PRO and AAC has been started.