The Design And Implemention Of DMA Controller In Embedded System-on-a-Chip

Peripheral equipments are necessary functional units on Digital Signal Processors(DSP). Direct Memory Access(DMA) is an important part of peripheral equipment in lower-power embedded DSP. It improves greatly the data processing speed and efficiency. So, it is important for researching and designing high performance DSP.X-DSP is an 16 bit fixed-point Digital Signal Processor developed by our task group. The paper studies the high performance DMA of X-DSP, designs and realizes a kind of high performance DMA by full custom method. Then it has performed the verification of DMA in system level simulation entironmentt. The simulation results has showed that the DMA unit runs rightly and steadily at 100MHz. Now, the DMA has fulfilled the whole design of X-DSP.The main content and production of this paper are showed as follows.1. The paper studies the theory and structure of DMA according to design specification of X-DSP, and puts forward a scheme of DMA with 6 channels, which can keep track of the contexts of six independent block transfers.2. The logic design of DMA is completed by modularization method. Some important circuits have been analyzed in detail.3. By full custom design method, each module of DMA is designed, analyzed and simulated from cell layout to full layout. The full layout is verified at last. The simulation results indicate that the DMA unit can meet X-DSP's need and achieve the goal of higher speed and smaller area.4. According the hiberarchy verification method,the DMA unit is verified in module level at first and is verified in system level in X-DSP at last. The result indicates that the DMA unit can meet X microprocessor's need completely.X-DSP has been taped out, and it can completely satisfy the request of design. Finally, the test result proves that the whole DMA unit is correct.