import RT-Thread@9217865c without bsp, libcpu and components/net

documentation/doxygen/mainpage.h

@@ -0,0 +1,49 @@
+/*
+ * This file is only used for doxygen document generation.
+ */
+
+/**
+ * @mainpage Introduction
+ * @author RT-Thread Development Team
+ * @version 1.2.0
+ *
+ * RT-Thread RTOS is an open source embedded real-time operating system and is
+ * designed specifically for small memory footprint platforms. The real-time and
+ * embedded characters are the most significant advantages of RT-Thread.
+ *
+ * - Real-Time Character
+ *
+ * RT-Thread has a real-time operating system kernel, with fully preempted
+ * multi-thread scheduler, inter-thread communication with timing sensitivity
+ * and transparent interrupt handling.
+ *
+ * - Embedded Character
+ *
+ * RT-Thread is suitable for embedded systems for small footprint characters.
+ * The kernel is implemented as a simple C library. The simplest application
+ * costs less than 1 Kbytes RAM on the ARM Cortex-M platform.
+ *
+ * @section kernel_arch RT-Thread Architecture
+ *
+ * RT-Thread system architecture is like:
+ * @image html System_Arch.png "Figure 1: RT-Thread Architecture"
+ *
+ * @section kernel_service Kernel API
+ *
+ * The Kernel APIs are the core APIs of RT-Thread, which supports the following
+ * features:
+ * - Multi-thread management and scheduler
+ * - Synchronization mechanisms, semaphore, recursive mutex and event set
+ * - Inter-thread communication, mailbox and message queue
+ * - Memory management, memory pool and dynamic heap memory management
+ * - Asynchronous timer
+ *
+ * For more details, please refer to @ref Kernel
+ *
+ * @section system_init System Initialization
+ *
+ * Once RT-Thread operating system starts up, the facility in system must be initialized
+ * firstly.
+ *
+ * For more details, please refer to @ref SystemInit
+ */