Analysis of the configuration example of FreeRTOS operating system

#ifndef FREERTOS_CONFIG_H
#define FREERTOS_CONFIG_H
//Call different files for different compilers// Make sure that stdint is only used by the compiler and not by the assembler#if defined(__ICCARM__) || defined(__CC_ARM) || defined(__GNUC__)
#include <>
extern uint32_t SystemCoreClock;
#endif
/***********************************************************************************************************************/
/* FreeRTOS basic configuration configuration options */
/**********************************************************************************************************************/
//#define configOVERRIDE_DEFAULT_TICK_CONFIGURATION 1 //Use non-systick interrupts as the scheduling clock#define configUSE_PREEMPTION 1 // Set 1: RTOS uses preemptive scheduler; Set 0: RTOS uses collaborative scheduler (time slice)/* Note:
 * In terms of multi-task management mechanism, the operating system can be divided into preemptive and collaborative.
 * Preemptive: Obtain the CPU usage rights based on the priority of the task.
 * Collaborative: After the task actively releases the CPU, switch to the next task.
 */
#define configUSE_TIME_SLICING 1 //1: Enable time slice scheduling (it is enabled by default)/* Note:
 * In order to realize time slice rotation scheduling, the system arranges all ready processes into a queue according to the first-in-first-out principle.  The new process is added to the end of the ready queue.
 * Whenever a process scheduling is executed, the process scheduler always selects the queue header process of the ready queue and lets it run a time slice on the CPU.
 * When the process uses up the time slice allocated to it, the system's timer issues a clock interrupt, and the scheduler stops the process's running and puts it at the end of the ready queue;
 * Then, assign the CPU to the queue header process of the ready queue, and also let it run a time slice, repeating over and over again.
 */
#define configUSE_PORT_OPTIMISED_TASK_SELECTION 1 //1: Use a special method to select the next task to be executed (hardware support)/* Note:
 * Some hardware running FreeRTOS has two ways to choose the next task to be performed: general methods and hardware-specific methods (hereinafter referred to as "special methods").
 * General method:
 * 1.configUSE_PORT_OPTIMISED_TASK_SELECTION is 0 or the hardware does not support this special method.
 * 2. Can be used for all FreeRTOS-supported hardware
 * 3. Completely implemented with C, with a slightly lower efficiency than that of special methods.
 * 4. No mandatory limit on the maximum available priority number
 * Special method:
 * 1. The configUSE_PORT_OPTIMISED_TASK_SELECTION must be set to 1.
 * 2. Assembly instructions that rely on one or more specific architectures (usually similar to calculating leading zeros [CLZ] instructions).
 * 3. More efficient than general methods
 * 4. Generally, the maximum number of available priority levels is 32
 * Generally, hardware calculation leading zero instructions. If the MCU does not have these hardware instructions, this macro should be set to 0!
 */
#define configUSE_TICKLESS_IDLE 0 //0: Low power tickless mode is not enabled/* Note:
 * Set 1: Enable low-power tickless mode; Set 0: Keep the system beat (tick) interrupted and run continuously
 *
 * If the low power consumption is turned on, it may cause download problems, because the program is sleeping, the following methods can be solved
 * Download method:
 * 1. Connect the development version normally
 * 2. Press and hold the reset button, click Download and release the reset button instantly
 *
 * 1. Connect BOOT 0 to high level (3.3V) through the jumper cap
 * 2. Power on again and download
 *
 * 1. Use FlyMcu to erase the chip and download it
 * STMISP -> Clear chip (z)
 */
#define configUSE_QUEUE_SETS 1 //1: Enable queue collection/* Note:
 * Queue collection: used to "listen" multiple queues and semaphores.
 * As long as any message comes, the task can be exited from the blocking state.
 */
#define configCPU_CLOCK_HZ (SystemCoreClock) //CPU frequency/* Note:
 * Write to the actual CPU core clock frequency, that is, the CPU instruction execution frequency, usually called Fclk
 * Fclk is the clock signal that supplies the CPU core. The CPU main frequency we call is XX MHz.
 * refers to this clock signal. Correspondingly, 1/Fclk is the CPU clock cycle;
 */
#define configTICK_RATE_HZ (( TickType_t )1000) //The clock beat frequency is 1000HZ, and the cycle is 1ms/* Note:
 * Frequency of beat interruption in RTOS system.
 * That is, the number of interrupts in one second, each time RTOS is interrupted, task schedule will be performed
 */
#define configMAX_PRIORITIES (32) //The maximum priority available/* Note:
 * When setting task priority, the smaller the number, the higher the priority
 */
#define configMINIMAL_STACK_SIZE ((unsigned short)128) //Stack size used by idle tasks/* Note:
 * Idle task is a task that the operating system forces the CPU to do in order to prevent the CPU from being idle.
 * Idle tasks are an indispensable task for FreeRTOS, because the FreeRTOS design requires that at least one task must be in operation.
 */
#define configMAX_TASK_NAME_LEN (16) //Length of task name string#define configUSE_16_BIT_TICKS 0 //The data type of the system beat counter variable,//1 represents 16-bit unsigned shaping, and 0 represents 32-bit unsigned shaping#define configIDLE_SHOULD_YIELD 1 //1: Idle tasks give up CPU usage rights to other user tasks with the same priority#define configUSE_TASK_NOTIFICATIONS 1 //1: Turn on the task notification function, and turn on by default#define configUSE_MUTEXES 1 //1: Use mutually exclusive semaphores#define configQUEUE_REGISTRY_SIZE 8 //Set the semaphore and message queues that can be registered#define configCHECK_FOR_STACK_OVERFLOW 0 //Not using stack overflow detection function/* Note:
 * Enable stack overflow detection if it is greater than 0. If this function is used
 * The user must provide a stack overflow hook function, if used
 * This value can be 1 or 2, because there are two stack overflow detection methods */
#define configUSE_RECURSIVE_MUTEXES 1 //1: Use recursive mutex semaphores#define configUSE_COUNTING_SEMAPHORES 1 //1: Use count semaphores#define configUSE_APPLICATION_TASK_TAG 0 //No tags to tasks (default not)/*****************************************************************
 FreeRTOS and memory application related configuration options
 *********************************************************************
#define configSUPPORT_DYNAMIC_ALLOCATION 1 //Support dynamic memory application#define configTOTAL_HEAP_SIZE ((size_t)(32*1024)) //All total heap sizes of the system/***************************************************************
 FreeRTOS configuration options related to hook functions
 ******************************************************************
#define configUSE_IDLE_HOOK 0 // Set 1: Use the idle hook; Set 0: Ignore the idle hook/* Note:
 * The idle task hook is a function, which is implemented by the user.
 * FreeRTOS specifies the name and parameters of the function: void vApplicationIdleHook(void),
 * This function will be called in every idle task cycle
 * For RTOS tasks that have been deleted, idle tasks can free up the stack memory allocated to them.
 * Therefore, it is necessary to ensure that idle tasks can be executed by the CPU
 * It is very common to use the idle hook function to set the CPU into power saving mode
 * Cannot call API functions that cause idle tasks to block
 */
#define configUSE_TICK_HOOK 0 // Set 1: Use the time slice hook; Set 0: ignore the time slice hook/* Note:
 * The time slice hook is a function, which is implemented by the user.
 * FreeRTOS specifies the name and parameters of the function: void vApplicationTickHook(void)
 * Time slice interrupts can be called periodically
 * Functions must be very short and cannot use a large amount of stacks.
 * API functions ending with "FromISR" or "FROM_ISR" cannot be called
 */
/*xTaskIncrementTick function is called in the xPortSysTickHandler interrupt function.  Therefore, the execution time of the vApplicationTickHook() function must be very short*/
//Use memory application failed hook function#define configUSE_MALLOC_FAILED_HOOK 0 //No memory application failed hook function/********************************************************************
 FreeRTOS configuration options related to runtime and task status collection
 ************************************************************************
#define configGENERATE_RUN_TIME_STATS 0 //Not enabled runtime statistics function (used for general debugging)#define configUSE_TRACE_FACILITY 1 //Enable visual tracking debugging#define configUSE_STATS_FORMATTING_FUNCTIONS	1
/* When the following three functions are 1 at the same time as the macro configUSE_TRACE_FACILITY, the following three functions will be compiled.
 * prvWriteNameToBuffer()
 * vTaskList(),
 * vTaskGetRunTimeStats()
 */
/********************************************************************
 FreeRTOS coroutine-related configuration options
 ************************************************************************
#define configUSE_CO_ROUTINES 0 //1: Enable coroutines, files must be added after enabling coroutines#define configMAX_CO_ROUTINE_PRIORITIES ( 2 ) //Number of effective priority for coroutines/***********************************************************************
 FreeRTOS configuration options related to software timer
 ************************************************************************
#define configUSE_TIMERS 1 //1: Enable the software timer#define configTIMER_TASK_PRIORITY ( 2 ) //Set software timer priority#define configTIMER_QUEUE_LENGTH 10 //Software timer queue length#define configTIMER_TASK_STACK_DEPTH (configMINIMAL_STACK_SIZE*2) //Software timer task stack size/************************************************************
 FreeRTOS optional function configuration options
 ******************************************************************
#define INCLUDE_xTaskGetSchedulerState          1
#define INCLUDE_vTaskPrioritySet		        1
#define INCLUDE_uxTaskPriorityGet		        1
#define INCLUDE_vTaskDelete				        1
#define INCLUDE_vTaskCleanUpResources	        1
#define INCLUDE_vTaskSuspend			        1
#define INCLUDE_vTaskDelayUntil			        1
#define INCLUDE_vTaskDelay				        1
#define INCLUDE_eTaskGetState			        1
#define INCLUDE_xTimerPendFunctionCall	        1
#define INCLUDE_uxTaskGetStackHighWaterMark     1
#define INCLUDE_xTaskGetHandle                  1
/******************************************************************
 FreeRTOS configuration options related to interrupts
 *********************************************************************
#ifdef __NVIC_PRIO_BITS
#define configPRIO_BITS       		__NVIC_PRIO_BITS
#else
#define configPRIO_BITS       		4
#endif
//STM32 is a 4-bit interrupt priority control, so here is 4 (different MCUs are different)#define configLIBRARY_LOWEST_INTERRUPT_PRIORITY 15 //Interrupt minimum priority//All 4-bit priority groups are given to the main priority, so there are 16-bit priority configurations in total: 0-15--The lowest priority is 15// Different MCUs are different#define configKERNEL_INTERRUPT_PRIORITY 		( configLIBRARY_LOWEST_INTERRUPT_PRIORITY << (8 - configPRIO_BITS) )	/* 240 */
//Set the kernel interrupt priority. This macro is used to set the interrupt priority of PendSV and tick timer.//The reason for the left shift of four bits here is: STM32 uses the high four bits starting from MSB as the priority configuration//In fact, this macro definition can be simplified to: #define configKERNEL_INTERRUPT_PRIORITY 0xF0#define configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY 5 //Set the maximum priority that the system can manage//This is the threshold priority mentioned by the BASEPRI register, which I set to 5 here.//That is, the priority level higher than 5 (priority level less than 5) is not managed by FreeRTOS!//This is for people to see, the following macro is for the system to see#define configMAX_SYSCALL_INTERRUPT_PRIORITY 	( configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY << (8 - configPRIO_BITS) )
//The reason why four bits need to be shifted left here: Same as above//Interrupts below this priority can safely call FreeRTOS's API functions, and interrupts above this priority cannot be prohibited.//The interrupt service function cannot call FreeRTOS's API functions!//That is: #define configMAX_SYSCALL_INTERRUPT_PRIORITY 0x50/*
 * The result of the above configuration is:
 * Interrupts with priority 0-4 will not be prohibited by FreeRTOS, and will not be delayed by executing the FreeRTOS kernel. Interrupts cannot be called.
 * Interrupts with priority 5-15 can be disabled by FreeRTOS, FreeRTOS API functions ending with FromISR can be called, and they can interrupt nesting
 * So: interrupts without using any FreeRTOS API can use all interrupt priority and they can interrupt nesting
 * Those tasks that require strict real-time performance can use 0-4 priority, such as barrier detection in quadcopters
 */
/****************************************************************
 FreeRTOS configuration options related to interrupt service functions
 *********************************************************************
#define xPortPendSVHandler 	PendSV_Handler
#define vPortSVCHandler 	SVC_Handler
//#define xPortSysTickHandler SysTickHandler implements it in the function itself#endif /* FREERTOS_CONFIG_H */