1. Support Port
FreeRTOS 当前已经支持20+编译器和 30+ 芯片结构。
`Port`: FreeRTOS 支持的编译器和处理器组合称之为一个 port。
2. File Structure
`FreeRTOSConfig.h`: 用户配置头文件
`FreeRTOS.h`: 对外头文件头文件
FreeRTOS
│ │
│ ├─Source Directory containing the FreeRTOS source files
| │
| ├─tasks.c FreeRTOS source file - always required
| ├─list.c FreeRTOS source file - always required
| ├─queue.c FreeRTOS source file - nearly always required
| ├─timers.c FreeRTOS source file - optional
| ├─event_groups.c FreeRTOS source file - optional
| └─croutine.c FreeRTOS source file - optional(rarely used now)
| │
| └─portable Directory containing all port specific source files
| │
| ├─MemMang Directory containing the 5 alternative heap allocation source files
| │
| ├─[compiler 1] Directory containing port files specific to compiler 1
| │ │
| │ ├─[architecture 1] Contains files for the compiler 1 architecture 1 port
| │ ├─[architecture 2] Contains files for the compiler 1 architecture 2 port
| │ └─[architecture 3] Contains files for the compiler 1 architecture 3 port
| │
| └─[compiler 2] Directory containing port files specific to compiler 2
| │
| ├─[architecture 1] Contains files for the compiler 2 architecture 1 port
| ├─[architecture 2] Contains files for the compiler 2 architecture 2 port
│ │
│ └─Demo Directory containing pre-configured and port specific FreeRTOS demo projects
│
FreeRTOS-Plus
│
├─Source Directory containing source code for some FreeRTOS+ ecosystem components
└─Demo Directory containing demo projects for FreeRTOS+ ecosystem components
2.1 Include Paths
用户使用时，必须包含以下头文件的路径：
FreeRTOS 核心头文件：FreeRTOS/Source/include.FreeRTOS 配置头文件：FreeRTOSConfig.h.目标 port 的头文件： FreeRTOS/Source/portable/[compiler]/[architecture].3. Data Types and Coding Style Guide
`portmacro.h` 中必须定义的数据类型 ：
1. `TickType_t`：如果 configUSE_16_BIT_TICKS == 1，uint16_t ；如果 configUSE_16_BIT_TICKS == 0，uint32_t ；
2. `BaseType_t`：等于CPU位宽，或者地址总线宽度， 如32bit 的结构就是32bit
3.1 变量命名
前缀_变量名称，其中前缀包括：
‘c’ for char;‘s’ for int16_t (short);‘l’ for int32_t (long),;‘x’ for BaseType_t and any other non-standard types (structures, task handles, queue handles,etc.);'u' for unsigned;‘p’ for pointer；3.2 函数命名
函数的前缀标识其返回值，前缀同变量命名前缀，另外：
‘prv’ 表示 仅在该文件内部起作用，即 File scope (private) functions。3.3 格式（formatting）
1 tab = 4 spaces。（Tab键等于4个空格）3.4 宏命名
宏命名采用 前缀_大写字母格式，其中前缀表示 该宏定义的
宏定义前缀
Num
Prefix
Location of macro definition
Example
1
port
portable.h or portmacro.h
portMAX_DELAY
2
task
task.h
taskENTER_CRITICAL()
3
pd
projdefs.h
pdTRUE
4
config
FreeRTOSConfig.h
configUSE_PREEMPTION
5
err
projdefs.h
errQUEUE_FULL
通用宏
Num
Macro
Value
1
pdTRUE
1
2
pdFALSE
0
3
pdPASS
1
4
pdFAIL
0