Predator: a predictable SDRAM memory controller

Memory requirements of intellectual property components (IP) in contemporary multi-processor systems-on-chip are increasing. Large high-speed external memories, such as DDR2 SDRAMs, are shared between a multitude of IPs to satisfy these requirements at a low cost per bit. However, SDRAMs have highly variable access times that depend on previous requests. This makes it difficult to accurately and analytically determine latencies and the useful bandwidth at design time, and hence to guarantee that hard real-time requirements are met. The main contribution of this paper is a memory controller design that provides a guaranteed minimum bandwidth and a maximum latency bound to the IPs. This is accomplished using a novel two-step approach to predictable SDRAM sharing. First, we define memory access groups, corresponding to precomputed sequences of SDRAM commands, with known efficiency and latency. Second, a predictable arbiter is used to schedule these groups dynamically at run-time, such...

• Type: Conference
• Year: 2007
• Where: CODES
• Authors: Benny Akesson, Kees Goossens, Markus Ringhofer
• Keywords: CODES 2007, Hardware-Software Codesign, Maximum Latency Bound, Memory Controller, Predictable Sdram Sharing