Geode GXLV Processor Series Low Power Integrated x86 Solutions

Geode GXLV Processor Series4.0 Integrated FunctionsThe integrated functions in the Geode GXLV processorare:• Internal bus interface• SDRAM memory controller• High-performance 2D graphics accelerator• Display controller with separate CRT and TFT datapaths• PCI bridgeThe design organizes the memory controller, graphicspipeline and display controller into a Unified MemoryArchitecture (UMA). UMA simplifies system designs andsignificantly reduces overall system costs associated withhigh chip count, small footprint designs. Performance degradationin traditional UMA systems is reduced throughthe use of National Semiconductor’s Display CompressionTechnology (DCT) architecture.Figure 4-1 shows the major functional blocks of the GXLVprocessor and how the Internal Bus Interface Unit operatesas the interface between the processor’s core unitsand the integrated functions.This section details how the integrated functions andInternal Bus Interface Unit operate and their respectiveregisters.Write-BackCache UnitMMUIntegerUnitFPUC-BusInternal Bus Interface UnitX-BusIntegratedFunctionsGraphics Memory Display PCIPipeline Controller Controller ControllerSDRAM Port CS5530 PCI Bus(CRT/LCD TFT)Figure 4-1. Internal Block Diagramwww.national.com 96 Revision 1.3