Further edits of documentation for clarity (#6156)

* Overhaul of document, fixing multiple grammar mistakes and editing for clarity

* Further documentation grammar and spelling fixes

documentation/introduction/introduction.md

 # RT-Thread Introduction 
 
-As a beginner of RTOS, you might be new to RT-Thread. However, with a better understanding of it overtime, you will gradually discover the charm of RT-Thread and its advantages over other RTOSs of the same type. RT-Thread is an Embedded Real-time Operating System (RTOS) . After nearly 12 years of experiences accumulated, along with the rise of the Internet of Things, it is evolving into a powerful, component-rich IoT operating system.  
+As a beginner of Real-time Operating Systems (RTOS), you might be new to RT-Thread. However, with a better understanding of it over time, you will gradually discover the charm of RT-Thread and its advantages over other RTOSs of the same type. RT-Thread is an RTOS. With over 16 years of experience accumulated, along with the rise of the Internet of Things (IoT), it is evolving into a powerful, component-rich IoT operating system.  
 
 ## RT-Thread Overview 
 
-RT-Thread, short for Real Time-Thread, as its name implies, is an embedded real-time multi-threaded operating system. One of its basic properties is to support multi-tasking. Allowing multiple tasks to run at the same time does not mean that the processor actually performed multiple tasks at the same time. In fact, a processor core can only run one task at a time. Every task is executed quickly, and through the task scheduler  (the scheduler determines the sequence according to priority),  the tasks are switched rapidly which gives the illusion that multiple tasks are running at the same time. In the RT-Thread system, the task is implemented by threads. The thread scheduler in RT-Thread is the task scheduler mentioned above.
+RT-Thread, short for Real Time-Thread, is an embedded real-time multi-threaded operating system. One of its main purposes is to support multi-tasking. Allowing multiple tasks to run simultaneously does not mean that the processor actually performs multiple tasks at the same time - a processor core can only run one task at a time. Every task is executed quickly, and through the task scheduler which determines the sequence according to priority, the tasks are switched rapidly, giving the illusion that multiple tasks are running at the same time. In the RT-Thread system, tasks are implemented by threads, and scheduled by the task scheduler.
 
-RT-Thread is mainly written in C language, easy to understand and easy to port. It applies object-oriented programming methods to real-time system design, making the code elegant, structured, modular, and very tailorable. For resource-constrained Microcontroller Unit (MCU) systems, NANO  version (NANO is a minimum kernel officially released by RT-Thread in July 2017) that requires only 3KB of Flash and 1.2KB of RAM memory resources can be tailored with easy-to-use tools; for resource-rich IoT devices, RT-Thread can use the on-line software package management tool, together with system configuration tools, to achieve intuitive and rapid modular cutting, seamlessly import rich Software f0  eature packs, thus achieving complex functions like Android's graphical interface and touch sliding effects, smart voice interaction effects, and so on.
+RT-Thread is mainly written in the C programming language, making it easy to understand and port. It applies object-oriented programming methods to real-time system design, making the code elegant, structured, modular, and very customizable. RT-Thread comes in a few varieties - the NANO version is a minimal kernel that requires only 3KB of flash and 1.2KB of RAM, which can be tailored with easy-to-use tools. For resource-rich IoT devices, RT-Thread can use an online software package management tool, together with system configuration tools, to achieve an intuitive and rapid modular design, while being able to seamlessly import rich software featurepacks. Through this, complex functions like Android's graphical interface, touch sliding effects, smart voice control and more can be easily created.
 
-Compared with the Linux operating system, RT-Thread is small in size, low in cost, low in power consumption and fast in startup. In addition, RT-Thread has high instantaneity and low occupation, which is very suitable for various resource constraints (such as cost, power consumption, etc.). Although the 32-bit MCU is its main operating platform, other CPUs, ones with MMU, ones based on ARM9, ARM11 and even the Cortex-A series CPUs are suitable for RT-Thread in specific applications.
+Compared with the Linux operating system, RT-Thread is small in size, low in cost, low in power consumption and fast in startup. In addition, RT-Thread is highly responsible, with low resource usage, which is ideally suitable for various resource constraints such as cost, power consumption, etc. Although the 32-bit MCU is its main operating platform, other CPUs, such as ones with MMU, ones based on ARM9, ARM11 and even the Cortex-A series CPUs are suitable for RT-Thread in specific applications.
 
 ## License Agreement
 
-The RT-Thread system is a completely open source system, the 3.1.0 version and its earlier versions follow the GPL V2 + open source license agreement. Versions from the 3.1.0 version onwards follow the Apache License 2.0 open source license agreement. The RT-Thread system can be used free of charge in commercial products and does not require opening private code to the public.
+The RT-Thread system is a completely open source system, the 3.1.0 version and its earlier versions follow the GPL V2 + open source license agreement. Versions from the 3.1.0 version onwards follow the Apache License 2.0 open source license agreement. The RT-Thread system can be used free of charge in commercial products and does not require opening private code up to the public.
 
 ## RT-Thread Frame
 
-In recent years, the concept of Internet of Things (IoT) has become widely known , and the Internet of Things market has developed rapidly. The networking of embedded devices is the trend of the times. Terminal networking has greatly increased the complexity of software. The traditional RTOS kernel can hardly meet the needs of the market. In this case, the concept of the Internet of Things Operating System (IoT OS) came into being. **IoT operating system refers to the software platform that is based on operating system kernel (like RTOS, Linux, etc.) and includes relatively complete middleware components such as file system, graphics library, etc. It is low in consumption and high in secure, abides by the Communication Protocol and has cloud-connect abilities.** RT-Thread is an IoT OS. 
+In recent years, the concept of the Internet of Things has become widely known, and the IoT market has developed rapidly. The networking of embedded devices is the trend of the times. Terminal networking has greatly increased the complexity of software, and traditional RTOS kernels can hardly meet the needs of the market. For this reason, the concept of the Internet of Things Operating System (IoT OS) came into being. **IoT operating system refers to the software platform that is based on operating system kernel (like RTOS, Linux, etc.) and includes relatively complete middleware components such as a file system, graphics library, etc. It has low overhead and high security, abides by the Communication Protocol and is capable of connecting to the cloud.** RT-Thread is an IoT OS. 
 
-One of the main differences between RT-Thread and many other RTOS such as FreeRTOS and uC/OS is that it is not only a real-time kernel, but also has a rich middle-tier component, as shown in the following figure.
+One of the main differences between RT-Thread and many other RTOSs such as FreeRTOS and uC/OS is that it is not only a real-time kernel, but also has a rich middle-tier component, as shown in the following figure.
 
 ![RT-Thread Software Framework](figures/02Software_framework_diagram.png)
 

documentation/quick-start/quick-start.md

-# Start Guide: Simulate STM32F103 on keil simulator
+# Start Guide: Simulate STM32F103 on Keil Simulator
 
-Because of its particularity, the embedded operating system is often closely related to the hardware platform. Specific embedded operating system can only run on specific hardware. For those who are new to the RT-Thread operating system, it is not easy to get a hardware module that is compatible with the RT-Thread operating system. However, with the development of computer technology, we can use software to simulate a  hardware module that has the ability to run RT-Thread operating system. This is the simulation environment called MDK-ARM produced by the company ARM.
+Because of its particularity, the embedded operating system is often closely related to the hardware platform, and specific embedded operating systems can only run on specific hardware. For those who might not have an RT-Thread compatible hardware module, or want to test out their ideas, a complete RT-Thread system can be developed in the simulation environment MDK-ARM.
 
-MDK-ARM (MDK-ARM Mi6hyicrocontroller Development Kit) software is a complete integrated development environment (IDE) from ARM. It includes efficient C/C++ compiler for ARM chips (ARM7, ARM9, Cortex-M series, Cortex-R series, etc.) ; project wizard and project management for various ARM devices, evaluation boards; simulator for software simulating hardware platform; and debuggers connected to simulators debugging the target board, common on-line simulators on the market are stlink jlink, etc. The simulator software in MDK-ARM uses a complete software simulation to interpret and execute  machine instructions from ARM and implement some peripheral logic to form a complete virtual hardware environment, enabling users to execute the corresponding target program on the computer without using real hardware platform.
+MDK-ARM (Microcontroller Development Kit - ARM) is a complete integrated development environment (IDE) from ARM. It includes an efficient C/C++ compiler for ARM chips (ARM7, ARM9, Cortex-M series, Cortex-R series, etc.), a project wizard and project management for various ARM devices and evaluation boards and a simulator for simulating hardware platforms in software. It supports debuggers connected to simulators debugging the target board, such as the commonly available ST-Link, J-Link, etc. The simulator software in MDK-ARM uses a complete software simulation to interpret and execute machine instructions from ARM and implement some peripheral logic to form a complete virtual hardware environment, enabling users to execute the corresponding target program on the computer without using a real hardware platform.
 
-Because of its full STM32F103 software simulation environment, the MDK-ARM integrated development environment gives us the opportunity to run object code directly on the computer without using a real hardware environment . This simulator platform can completely virtualize  the various operating modes and peripherals of the ARM Cortex-M3, such as exceptional interrupts, clock timers, serial ports, etc., which is almost identical to the real hardware environment. Practice has also proved that the RT-Thread introductory sample used in this article, after compiling into binary code, can not only run on the simulator platform, but also can run normally on the real hardware platform without modification.
+Because of its full STM32F103 software simulation environment, the MDK-ARM integrated development environment gives us the opportunity to run object code directly on the computer without using a real hardware environment. This simulator platform can completely virtualize the various operating modes and peripherals of the ARM Cortex-M3, such as exceptions, interrupts, clock timers, serial ports, etc., which is almost identical to the real hardware environment. RT-Thread can run on both the simulated environment and on real hardware.
 
-Next, we will select the MDK-ARM integrated development environment as the target hardware platform to observe how the RT-Thread operating system works.
+What will follow is a demonstration of RT-Thread running on a simulated STM32F103 microcontroller through MDK-ARM.
 
 ## Preparation
 
-MDK development environment: MDK-ARM 5.24 (official or evaluation version, version 5.14 and above) needs to be installed. This version is also a relatively new version, which can provide relatively complete debugging functions. How to install can be referred to the  [Keil MDK Installation](./keil-installation/keil-installation.md).
+MDK development environment: MDK-ARM 5.24 (official or evaluation version, version 5.14 and above) needs to be installed. This version is a relatively new version, which can provide relatively complete debugging functions. An installation guide can be found here: [Keil MDK Installation](./keil-installation/keil-installation.md).
 
 ## First acquaintance with RT-Thread
 
-As an operating system, what is the code size of RT-Thread? Before we can figure this out, the first thing we need to do is to get an example of RT-Thread that corresponds to this manual. This example can be obtained from the following link:
+To see the code size of RT-Thread we first need to get an example of RT-Thread that is suited for this environment, which can be obtained from the following link:
 
 [RT-Thread Simulator Sample](./rtthread_simulator_v0.1.0.zip)
 
-This example is a zip file, unzip it. Here, we decompressed it to D:/. The directory structure after decompression is as shown below:
+This example is a zip file, unzip it. The directory structure after decompression is as shown below:
 
 ![rtthread_simulator_v0.1.0 Code Directory ](./figures/7.png)
 
@@ -37,7 +37,7 @@ drivers     | Driver of RT-Thread, implementations of bottom driver of different
 Libraries   | ST's STM32 firmware library file.
 kernel-sample-0.1.0    | Kernel sample for RT-Thread.
 
-In the directory, there is project.uvprojx file, which is an MDK5 project file in the sample referenced in this manual. Double-click "project.uvprojx" icon to open the project file:
+In the directory, there is a file with the name "project.uvprojx", which is an MDK5 project file in the sample referenced in this manual. Double-click "project.uvprojx" icon to open the project file:
 
 ![Open the project](./figures/5.png)
 
@@ -54,24 +54,24 @@ Under the "Project" column on the left side of the main window of the project, y
 | DeviceDrivers   | The corresponding directory is rtthread_simulator_v0.1.0/rt-thread/components/drivers, used to store driver framework source code of RT-Thread. |
 | finsh           | The corresponding directory is rtthread_simulator_v0.1.0/rt-thread/components/finsh, used to store command line of RT-Thread finsh command line component. |
 
-Now let's click the button from the toolbar on the top the window,![img](./figures/compile.jpg), compiling the project as shown:
+Now click the button from the toolbar on the top the window, ![img](./figures/compile.jpg), to compile the project as shown:
 
 ![compiling](./figures/9.png)
 
 The result of the compilation is displayed in the "Build Output" bar at the bottom of the window. If nothing else, it will say "0 Error(s), * Warning(s)." on the last line, that is, there are no errors or warnings.
 
-After compiling RT-Thread/STM32, we can simulate running RT-Thread through the MDK-ARM simulator. Click ![img](./figures/debug.jpg)at the top right of the window or directly hit Ctrl+F5 to enter the simulation interface and hit F5 to start, then click the button in the toolbar shown in the screen shot or select “View→Serial Windows→UART#1” in the menu bar to open the serial port 1 window. You can see that the output of the serial port only shows the LOGO of RT-Thread. This is because the user code is empty and the result of its simulation is as shown:
+After compiling RT-Thread/STM32, we can simulate running RT-Thread through the MDK-ARM simulator. Click ![img](./figures/debug.jpg) at the top right of the window or directly hit Ctrl+F5 to enter the simulation interface and hit F5 to start, then click the button in the toolbar shown in the screen shot or select “View→Serial Windows→UART#1” in the menu bar to open the serial port 1 window. You can see that the output of the serial port only shows the logo of RT-Thread. This is because the user code is empty and the result of its simulation is as shown:
 
 ![simulate RT-Thread1](./figures/10.png)
 
->We can output all the commands supported by the current system by inputting the Tab key or `help + enter ` , as shown in the following figure.
+>We can output all the commands supported by the current system by inputting the Tab key or `help + enter` , as shown in the following figure.
 
 ![simulate RT-Thread2](./figures/6.png)
 
 
 ## User Entry Code
 
-The above startup code is basically related to the RT-Thread system, so how do users add initialization code for their own applications? RT-Thread uses main function as the user code entry, all you need to do is just add your own code to the main function.
+The above startup code is related to the RT-Thread system, so how do users add initialization code for their own applications? RT-Thread uses main function as the user code entry, all you need to do is just add your own code to the main function.
 
 ```c
 int main(void)
@@ -85,7 +85,7 @@ int main(void)
 
 ## Example of a Marquee
 
-For technical engineers working on electronics, marquee is probably the simplest example, it is like the first program Hello World in every programming language that programmers learned. So we will start with a marquee in the following example, to make it periodically update (turn on or off) the LED.
+For technical engineers working on electronics, marquee is probably the simplest example, the equivalent of Hello World in every programming language programmers learn. So we will start with a marquee in the following example, to make it periodically update (turn on or off) the LED.
 
 Under UART#1, input msh command: led and then click Enter to run it, as shown:
 
@@ -144,7 +144,7 @@ Cause: This type of problem is usually caused by installation of ADS, when ADS a
 Solution:
 
 - Delete ADS environment variables
-- Uninstall ADS and keil, restart the computer, reload keil
+- Uninstall ADS and Keil, restart the computer, reload Keil
 
 
 

documentation/thread/thread.md

@@ -81,9 +81,9 @@ struct rt_thread
 
 RT-Thread's threads have a dependent stack. When the thread is switched, the context of the current thread is stored in the stack. When the thread is about to resume operation, the context information is read from the stack and recovered.
 
-Thread stack is also used to store local variables in functions: local variables in functions are applied from the thread stack space; local variables in functions are initially allocated from registers (ARM architecture), when this function calls another function, these local variables will be placed on the stack.
+The thread stack is also used to store local variables in functions: local variables in functions are applied from the thread stack space; local variables in functions are initially allocated from registers (ARM architecture), when this function calls another function, these local variables will be placed on the stack.
 
-For the first run of thread, context can be constructed manually to set initial environment like: entry function (PC register), entry parameter (R0 register), return position (LR register), current machine operating status (CPSR register).
+For the first run of thread, the context can be constructed manually to set initial environment like: entry function (PC register), entry parameter (R0 register), return position (LR register), current machine operating status (CPSR register).
 
 The growth direction of the thread stack is closely related to the CPU architecture. Versions before RT-Thread 3.1.0 only allow the stack to grow from high address to low address. For the ARM Cortex-M architecture, the thread stack can be constructed as shown below.
 
@@ -109,7 +109,7 @@ The five states of a thread in RT-Thread are shown in the following table:
 
 The priority of the RT-Thread thread indicates the thread's priority of being scheduled. Each thread has its priority. The more important the thread, the higher priority it should be given, resulting in a higher chance of being scheduled.
 
-RT-Thread supports a maximum of 256 thread priorities (0~255). The lower the number, the higher the priority and 0 is the highest priority. In some systems with tight resources, you can choose system configurations that only support 8 or 32 priorities according to the actual situation; for the ARM Cortex-M series, 32 priorities are commonly used. The lowest priority is assigned to idle threads by default and is not used by users. In the system, when a thread with a higher priority is ready, the current thread with the lower priority will be swapped out immediately, and the high-priority thread will preempt the processor.
+RT-Thread supports a maximum of 256 thread priorities (0~255). The lower the number, the higher the priority, with 0 being the highest priority. In some systems with tight resources, you can choose system configurations that only support 8 or 32 priorities according to the actual situation; for the ARM Cortex-M series, 32 priorities are commonly used. The lowest priority is assigned to idle threads by default and is not used by users. In the system, when a thread with a higher priority is ready, the current thread with the lower priority will be swapped out immediately, and the high-priority thread will preempt the processor.
 
 #### Time Slice