开发工具调整功耗的微控制器

　　开发工具调整功耗的微控制器

　　一方面将许多设备组成了物联网，对低能耗的要求。解决这一需求需要在多层次的整体战略的优化。一个成功的设计需要的不仅仅是选择低功耗元件，而且还使用软件勉强可用的电池容量由这些组件，以最有效的方式一起工作。即使细微的变化，硬件和软件的实施可以使整体能源使用的巨大差异。

　　大多数物联网设备的核心是一个微控制器（MCU）设计的高能效。一个典型的低能量MCU包括一个智能外设阵列控制的I / O和必要的系统功能的核心处理器。串行端口（UART）通常能够自动发送和接收数据，而在处理器内核上运行的软件只需要从适当的缓冲区传输字节，一旦数据接收完成。与链接的DMA传输可用的设备如从Silicon Labs EFM32系列MCU的壁虎，甚至相互作用可以被最小化。在这种情况下，处理器核心只需要唤醒检查内存的内容，一旦整个消息已收到。

　　By allowing peripherals to manage I/O， the MCU can spend much of its time in sleep mode， where many parts of the MCU will be shut down and not draw power. Duty cycle is the ratio of time spent in active mode vs time spent asleep. A low duty cycle is important to battery powered IoT applications since sleep modes draw mere microamps， while active mode typically draws several orders of magnitude more.

　　A low duty cycle allows the processor core to sleep for a majority of the time， waking only to collect data or to communicate when necessary. The key to implementing a low duty cycle strategy is understanding how the software interacts with the hardware. Functions that cause the MCU to be awake too long need to be identified and then replaced or rewritten if possible. Traditionally， this has been difficult to achieve early in the development phase because such identification relies on finished hardware for testing.

　　The Pearl Gecko starter kit and similar evaluation boards from Silicon Labs include an Advanced Energy Monitor （AEM） function. When used in combination with the advanced tools in the company’s Simplicity Studio， it provides valuable insight into how much energy an application requires during the software development cycle. The information not only shows the effectiveness of sleep modes， but also function-level optimizations.