飞思卡尔S12X存储器分页机制分析

Paging Mechanism Analysis of Freescale S12X Memory

飞思卡尔S12X是新一代的双核微控制器,拥有卓越的性能,堪比32位微控制器,已成为汽车行业领先的16位解决方案。S12X系列MCU扩展了其存储器空间,深刻理解存储器分页机制是合理高效利用存储器资源的前提。存储器分页机制存在一定的技术深度,故本文从集成在飞思卡尔S12X系列MCU中为扩展存储器空间而设置的存储器映像控制模块MMC入手,介绍其中的GPAGE、PPAGE、RPAGE、EPAGE寄存器,讲解如何利用MCU的16位地址线和这些寄存器,实现对23位全局地址空间的访问。

Freescale S12X is the next new generation of dual-micro-controller with excellent performance that catches up with 32bit micro controller unit,has become the leading solution of automotive industry.S12X MCU family expands its memory space.Deep understanding of memory paging mechanism is premise of efficient use of memory resources.Because memory paging mechanism is in certain technical depth,this paper starts from memory mapping control module integrated in Freescale S12X MCU that is for the expansion of memory space,introduces GPAGE,PPAGE,RPAGE,EPAGE registers,and explains how to access the 23-bit global address space using 16-bit address and these registers.