Overview In today's deeply embedded, often battery-powered systems, the need to ensure system power budgets are adhered to is essential whilst still ensuring that system functionality is effectively implemented. Coupled with this is the desire to clock the system processor as slowly as possible in order to achieve minimum power consumption, but fast enough to ensure sufficient system performance. Balancing these conflicting requirements can be extremely difficult and it is in this area of functionality that Direct Memory Access (DMA) controllers can offer system developers a significant design advantage.
Benefits DMA controllers are devices that allow data to be transferred to or from memory or peripherals bypassing the system Central Processing Unit (CPU).
In general terms, this enables one of two possible outcomes; either it means that the CPU can be occupied with other potentially higher priority system tasks whilst the DMA controller ensures that no parts of the system starve from data shortages or the CPU can enter a low power mode for longer but with critical data still being transferred about the system. Applications DMA controllers have historically been used for tasks such as moving data to and from disk drives in personal computers but today they can be found in many System On Chip (SoC) devices supporting a number of roles, including video and audio processing in mobile applications, packet routing in networking applications and HDTV products. Portfolio ARM has a number of DMA controllers with varying characteristics that make them suitable for multiple SoC roles. ARM
Product | Description | Gate Count | Technical
Reference
Manual | | PL230 | Configurable AHB Micro-DMA Controller | 3-10k gates1 | (988KB PDF) | | PL081 | 2-Channel AHB DMA Controller | 24.9k gates | (990KB PDF) | | PL080 | 8-channel AHB DMA Controller | 82k gates | (1MB PDF) | | PL330 | Configurable AXI DMA Controller | 20-200 | 2 |
Note 1 - Gate counts for configurable PrimeCells show a range of typical, usable configurations Note 2 - Please contact ARM for access to these documents The Micro-DMA controller PrimeCell® (PL230) is ideally suited to micro-controller applications as well as the more traditional deeply embedded ASIC platforms. This PrimeCell DMA controller can be configured to suit to your system requirements through AMBA® Designer allowing system architectural exploration prior to implementation. Its extremely small size and ease of implementation will allow system designers to rapidly design DMA controllers into their systems and quickly start seeing efficiency increases. The Configurable AXI DMA Controller (PL330) is a high performance, AMBA compliant DMA Controller. It exhibits superior flexibility due to its programmability and configurability. Configurability optimizes the gate count for your target system: 20-40K for a low end configuration (32 bit AXI, up to 4 channels), 40-80K gates for typical configuration and 150K-200K for high end configurations (128 bit AXI, multiple channels, deep data buffer). For more information on these or other AMBA devices, please contact your local ARM representative. Alternatively you can submit an email enquiry here. Back to Top | 
