设计师面对复杂的选择为MCUs和微处理器之间的界限模糊

　　设计师面对复杂的选择为MCUs和微处理器之间的界限模糊

　　看看微控制器（MCU）的高端部分，你会发现具有微架构和指令集特性的集成电路类似于微处理器中的芯片。事实上，企业如德克萨斯仪器（TI）和飞思卡尔提供单片机和嵌入式微处理器与一个共享的遗产有针对性。不过，这两个部分之间的差异很大，从公司的芯片设计和制造策略到集成的功能集以及硬件中根深蒂固的软件支持。嵌入式设计团队在考虑设备选择之前，必须仔细考虑其应用，以便在选择MCU或微处理器路径时做出正确的选择。

　　从高层次上看微控制器和微处理器技术，它们似乎相互交叉。在两个阵营中都有兼容的或重叠的指令集，MCU时钟频率已经升级到接近微处理器端部的一个点。

　　Scalable families

　　Let us consider some examples of what appears to be a smooth progression of compatible processor technology moving up an MCU product line and into the microprocessor area. Freescale offers the Kinetis MCU family based on the ARM Cortex-M4 core， including products such as the K10， K20， K30， K40， and K60 MCUs. On the microprocessor side， Freescale offers the i.MX microprocessor family. The i.MX1/2， i.MXL， and i.MXS families are based on an ARM9 core. The i.MX3x family is based on an ARM11 core， and the i.MX5x family is based on an ARM Cortex-A8 core.

　　Clearly there are differences in the CPU cores used across the Freescale ARM-based portfolio. We will discuss architectural differences in cores throughout the article， but in a simplified comparison， they all support the same basic instruction set. The Cortex-M4 core is optimized for low power and a smaller die size. The ARM9， ARM11， and ARM Cortex-A8 progression basically represents a scaling of performance capabilities. We could make largely the same type of comparison with Freescale‘s PowerPC-based portfolio including the MPC6x and MPC7xmicroprocessor families and the PowerPC MCU family.