The FreeRTOS operating system is a completely free, open-source, and portable real-time operating system.
1. Add files
First, prepare a basic project and FreeRTOS source code, the source code is decompressed as shown in the figure
Create a new folder FreeRTOS in the basic project, and copy all the files under the Source file in the FreeRTOS file in the FreeRTOS source code to the FreeRTOS of our basic project.
Next, enter the basic project FreeRTOS file, enter portable, leaving only keil, MemMang and RVDS
Then, we open keil and add it.
Click on the small box, create a new group and add files as follows
Next click on the magic wand to add a location
After compiling, I found a lot of errors and could not open "FreeRTOSConfig.h".
We are going to find "FreeRTOSConfig.h" in the FreeRTOS source code. Open the FreeRTOS folder and enter the CORTEX_STM32F103_Keil folder, copy the corresponding files to the FreeRTOS folder of our basic project template.
Recompile and complete.
2. Modify the file
Open sys.h and change the macro SYSTEM_SUPPORT_OS to 1.
Open usart.c, put
changed to
Modify the interrupt function of USART1_IRQHandler as follows:
void USART1_IRQHandler(void) //串口1中断服务程序
{
u8 Res;
if(USART_GetITStatus(USART1, USART_IT_RXNE) != RESET) //接收中断(接收到的数据必须是0x0d 0x0a结尾)
{
Res =USART_ReceiveData(USART1); //读取接收到的数据
if((USART_RX_STA&0x8000)==0)//接收未完成
{
if(USART_RX_STA&0x4000)//接收到了0x0d
{
if(Res!=0x0a)USART_RX_STA=0;//接收错误,重新开始
else USART_RX_STA|=0x8000; //接收完成了
}
else //还没收到0X0D
{
if(Res==0x0d)USART_RX_STA|=0x4000;
else
{
USART_RX_BUF[USART_RX_STA&0X3FFF]=Res ;
USART_RX_STA++;
if(USART_RX_STA>(USART_REC_LEN-1))USART_RX_STA=0;//接收数据错误,重新开始接收
}
}
}
}
} Modify delay.c, directly copy the modified delay.c
#include "delay.h"
#include "sys.h"
#if SYSTEM_SUPPORT_OS
#include "FreeRTOS.h" //FreeRTOS使用
#include "task.h"
#endif
static u8 fac_us=0; //us延时倍乘数
static u16 fac_ms=0; //ms延时倍乘数,在ucos下,代表每个节拍的ms数
extern void xPortSysTickHandler(void);
//systick中断服务函数,使用ucos时用到
void SysTick_Handler(void)
{
if(xTaskGetSchedulerState()!=taskSCHEDULER_NOT_STARTED)//系统已经运行
{
xPortSysTickHandler();
}
}
//初始化延迟函数
//SYSTICK的时钟固定为AHB时钟，基础例程里面SYSTICK时钟频率为AHB/8
//这里为了兼容FreeRTOS，所以将SYSTICK的时钟频率改为AHB的频率！
//SYSCLK:系统时钟频率
void delay_init()
{
u32 reload;
SysTick_CLKSourceConfig(SysTick_CLKSource_HCLK);//选择外部时钟 HCLK
fac_us=SystemCoreClock/1000000; //不论是否使用OS,fac_us都需要使用
reload=SystemCoreClock/1000000; //每秒钟的计数次数 单位为M
reload*=1000000/configTICK_RATE_HZ; //根据configTICK_RATE_HZ设定溢出时间
//reload为24位寄存器,最大值:16777216,在72M下,约合0.233s左右
fac_ms=1000/configTICK_RATE_HZ; //代表OS可以延时的最少单位
SysTick->CTRL|=SysTick_CTRL_TICKINT_Msk; //开启SYSTICK中断
SysTick->LOAD=reload; //每1/configTICK_RATE_HZ秒中断一次
SysTick->CTRL|=SysTick_CTRL_ENABLE_Msk; //开启SYSTICK
}
//延时nus
//nus:要延时的us数.
//nus:0~204522252(最大值即2^32/fac_us@fac_us=168)
void delay_us(u32 nus)
{
u32 ticks;
u32 told,tnow,tcnt=0;
u32 reload=SysTick->LOAD; //LOAD的值
ticks=nus*fac_us; //需要的节拍数
told=SysTick->VAL; //刚进入时的计数器值
while(1)
{
tnow=SysTick->VAL;
if(tnow!=told)
{
if(tnow<told)tcnt+=told-tnow; //这里注意一下SYSTICK是一个递减的计数器就可以了.
else tcnt+=reload-tnow+told;
told=tnow;
if(tcnt>=ticks)break; //时间超过/等于要延迟的时间,则退出.
}
};
}
//延时nms
//nms:要延时的ms数
//nms:0~65535
void delay_ms(u32 nms)
{
if(xTaskGetSchedulerState()!=taskSCHEDULER_NOT_STARTED)//系统已经运行
{
if(nms>=fac_ms) //延时的时间大于OS的最少时间周期
{
vTaskDelay(nms/fac_ms); //FreeRTOS延时
}
nms%=fac_ms; //OS已经无法提供这么小的延时了,采用普通方式延时
}
delay_us((u32)(nms*1000)); //普通方式延时
}
//延时nms,不会引起任务调度
//nms:要延时的ms数
void delay_xms(u32 nms)
{
u32 i;
for(i=0;i<nms;i++) delay_us(1000);
}
When compiling, the error is as follows: Duplicate function definition
Open stm32f10x_it.c, which duplicate shields which!
报错L6218E: Undefined symbol xTaskGetSchedulerState (referred from delay.o).
Open FreeRTOS.h and modify it to 1.
Compile again without reporting an error!
3. Verify whether the transplantation is successful
Download the demo to the development board, there is a small problem, the light is not on, woo woo~
After comparing the routines, I finally searched for information and found that it was a problem with FreeRTOSConfig.h. Copy the FreeRTOSConfig.h of the routine, compile and upload the program, and solve it!
The transplant was successful!
