Android系统移植 里面详细介绍相关驱动的知识，如果喜欢底层的话可以尝试自己去修改-Android system transplanted inside the detailed knowledge of the relevant drive, if you like the bottom, then you can try to modify

android 心率功能底层驱动实现，针对展讯平台优化处理。。。(Realization of bottom driver of Android heart rate function)