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DioneOS (pronounced /djoneos/) is multitasking preemptive, real-time operating system. The system is designed for Texas Instruments MSP430x microcontrollers. Target microcontroller platform has limited resources, i.e. system clock frequency in tens of MHz and memories amount from tens to a few hundreds KB. The system is adapted to such conditions by providing its compact and efficient image. The efficiency term means here minimization of additional CPU load caused by the system usage. According to this definition, the system is more effective when it consumes less CPU time for execution of its internal parts (e.g. threads management). The DioneOS system is intended for autonomic devices where user interface has limited functions. The core functionality provided by the system is an environment for building multitasking firmware by means of standard, well known concepts (e.g. semaphores, timers, etc.). Because of the target domain of application, the system has not graphic user interface. ==Memory model== Texas Instruments company manufactures wide range of microcontrollers that use msp430 core. Depending on the version, the chip contains different amount of flash memory and RAM (e.g. msp430f2201 has 1KB/128B correspondingly, but msp430f5438 - 256KB/16KB). When the size of the memory exceeds 64 KB limit,〔it happens when the memory cannot fit in a range 0–64 KB〕 16 bits addressing is insufficient. Due to this constraint, chips with larger memory are equipped with extended core (msp430x). This version of the processor has wider registers (20 bits) and new instructions for processing them. At the time of compilation programmer selects the type of memory model ('near' or 'far') that is used for FLASH and RAM memories. This choice determines accessible memory range, hence when the FLASH above 64 KB limit is programmed, 'far' model must be used. The DioneOS supports 'far' model for code modules, so large firmware that uses extended FLASH can be developed and run under the system control. The system uses 'near' memory model for data segments. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「DioneOS」の詳細全文を読む スポンサード リンク
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