哪个ARM皮质CPU适合你的下一个基于单片机的应用程序？

　　哪个ARM皮质CPU适合你的下一个基于单片机的应用程序？

　　基于ARM的CPU在MCU世界普遍存在，并且经常有几个可用的来自同一个MCU的供应商。每个ARM CPU已经优化了一类特定的处理要求，从低端功率受限的应用到高功率性能优化，双核应用。最流行的ARM CPU今天在MCU设备似乎是皮质CPU。你如何决定哪一个ARM皮质CPU是正确的一个应用程序？让我们探讨的主要差异，一些比较流行的基于MCU的皮层看例子的实现，将帮助你决定哪一个是你的下一个设计。

　　Many options

　　It’s not unusual to find many different ARM Cortex CPUs within a single MCU family. The Cortex CPU and its optional extensions address a variety of application needs， but all have backward-compatible instruction sets， as illustrated in Figure 1. Starting with the Cortex-M0/M0+/M1 family， the instruction set is targeted for general-purpose data processing and IO tasks. The Cortex-M3 CPU adds advanced-data processing and bit-field manipulation instructions that speed up more complex control and general-purpose computational tasks. The Cortex-M4 CPU adds Digital-Signal processing （DSP） instructions and offers Single-Instruction Multiple-Data （SIMD） operations where the same data-processing instruction can operate on multiple-data sources at the same time. These specialized capabilities can dramatically accelerate complex data-processing tasks， like those found in audio and video applications. The Cortex-M4 CPU can also add a Floating Point Unit （FPU） when performance and precision are both important elements for the target algorithm. Analog sensing and motor control， for example， often use floating point for its precision， but high performance is required for fast-control loop closure.