直接修改drv_clk文件中的system_clock_config()函数
至于board.h中的
#define BSP_CLOCK_SOURCE ("HSE")
#define BSP_CLOCK_SOURCE_FREQ_MHZ ((int32_t)8)
#define BSP_CLOCK_SYSTEM_FREQ_MHZ ((int32_t)72)
推荐根据自己的情况更改 [ 但其实这个改不改并不会影响到时钟配置,因为RT_Thread压根好像没有使用这几个参数,目前看来是这样的2022/1/24 ]
startup_stm32f103xe.S文件
/* Call the clock system intitialization function.*/
bl SystemInit
/* Call static constructors */
/* bl __libc_init_array */
/* Call the application's entry point.*/
bl entry
bx lr
先执行SystemInit ,
再执行entry ,
system_stm32f1xx.c文件
void SystemInit (void)
{
/* Reset the RCC clock configuration to the default reset state(for debug purpose) */
/* Set HSION bit */
RCC->CR |= 0x00000001U;
/* Reset SW, HPRE, PPRE1, PPRE2, ADCPRE and MCO bits */
#if !defined(STM32F105xC) && !defined(STM32F107xC)
RCC->CFGR &= 0xF8FF0000U;
#else
RCC->CFGR &= 0xF0FF0000U;
#endif /* STM32F105xC */
/* Reset HSEON, CSSON and PLLON bits */
RCC->CR &= 0xFEF6FFFFU;
/* Reset HSEBYP bit */
RCC->CR &= 0xFFFBFFFFU;
/* Reset PLLSRC, PLLXTPRE, PLLMUL and USBPRE/OTGFSPRE bits */
RCC->CFGR &= 0xFF80FFFFU;
#if defined(STM32F105xC) || defined(STM32F107xC)
/* Reset PLL2ON and PLL3ON bits */
RCC->CR &= 0xEBFFFFFFU;
/* Disable all interrupts and clear pending bits */
RCC->CIR = 0x00FF0000U;
/* Reset CFGR2 register */
RCC->CFGR2 = 0x00000000U;
#elif defined(STM32F100xB) || defined(STM32F100xE)
/* Disable all interrupts and clear pending bits */
RCC->CIR = 0x009F0000U;
/* Reset CFGR2 register */
RCC->CFGR2 = 0x00000000U;
#else
/* Disable all interrupts and clear pending bits */
RCC->CIR = 0x009F0000U;
#endif /* STM32F105xC */
#if defined(STM32F100xE) || defined(STM32F101xE) || defined(STM32F101xG) || defined(STM32F103xE) || defined(STM32F103xG)
#ifdef DATA_IN_ExtSRAM
SystemInit_ExtMemCtl();
#endif /* DATA_IN_ExtSRAM */
#endif
#ifdef VECT_TAB_SRAM
SCB->VTOR = SRAM_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal SRAM. */
#else
SCB->VTOR = FLASH_BASE | VECT_TAB_OFFSET; /* Vector Table Relocation in Internal FLASH. */
#endif
}
因为还没有仔细研究ST公司的Reference文档 , 目前还不太清除具体做了什么,但是肯定是进行硬件初始化
component.c
int entry(void)
{
rtthread_startup();
return 0;
}
int rtthread_startup(void)
{
rt_hw_interrupt_disable();
/* board level initialization
* NOTE: please initialize heap inside board initialization.
*/
rt_hw_board_init();
/* show RT-Thread version */
rt_show_version();
/* timer system initialization */
rt_system_timer_init();
/* scheduler system initialization */
rt_system_scheduler_init();
#ifdef RT_USING_SIGNALS
/* signal system initialization */
rt_system_signal_init();
#endif
/* create init_thread */
rt_application_init();
/* timer thread initialization */
rt_system_timer_thread_init();
/* idle thread initialization */
rt_thread_idle_init();
/* start scheduler */
rt_system_scheduler_start();
/* never reach here */
return 0;
}
我们直接看rt_hw_board_init() 函数
board.c文件
RT_WEAK void rt_hw_board_init()
{
extern void hw_board_init(char *clock_src, int32_t clock_src_freq, int32_t clock_target_freq);
/* Heap initialization */
#if defined(RT_USING_HEAP)
rt_system_heap_init((void *) HEAP_BEGIN, (void *) HEAP_END);
#endif
hw_board_init(BSP_CLOCK_SOURCE, BSP_CLOCK_SOURCE_FREQ_MHZ, BSP_CLOCK_SYSTEM_FREQ_MHZ);
/* Set the shell console output device */
#if defined(RT_USING_DEVICE) && defined(RT_USING_CONSOLE)
rt_console_set_device(RT_CONSOLE_DEVICE_NAME);
#endif
/* Board underlying hardware initialization */
#ifdef RT_USING_COMPONENTS_INIT
rt_components_board_init();
#endif
}
再看hw_board_init()
drv_common.c
void hw_board_init(char *clock_src, int32_t clock_src_freq, int32_t clock_target_freq)
{
extern void rt_hw_systick_init(void);
extern void clk_init(char *clk_source, int source_freq, int target_freq);
#ifdef SCB_EnableICache
/* Enable I-Cache---------------------------------------------------------*/
SCB_EnableICache();
#endif
#ifdef SCB_EnableDCache
/* Enable D-Cache---------------------------------------------------------*/
SCB_EnableDCache();
#endif
/* HAL_Init() function is called at the beginning of the program */
HAL_Init();
/* enable interrupt */
__set_PRIMASK(0);
/* System clock initialization */
clk_init(clock_src, clock_src_freq, clock_target_freq);
/* disbale interrupt */
__set_PRIMASK(1);
rt_hw_systick_init();
/* Pin driver initialization is open by default */
#ifdef RT_USING_PIN
extern int rt_hw_pin_init(void);
rt_hw_pin_init();
#endif
/* USART driver initialization is open by default */
#ifdef RT_USING_SERIAL
extern int rt_hw_usart_init(void);
rt_hw_usart_init();
#endif
}
我们再看clk_init()
drv_clk.c
void clk_init(char *clk_source, int source_freq, int target_freq)
{
system_clock_config(target_freq);
}
void system_clock_config(int target_freq_Mhz)
{
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
/** Initializes the RCC Oscillators according to the specified parameters
* in the RCC_OscInitTypeDef structure.
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
RCC_OscInitStruct.HSEState = RCC_HSE_ON;
RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
Error_Handler();
}
/** Initializes the CPU, AHB and APB buses clocks
*/
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV2;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
{
Error_Handler();
}
}
看到这,我直接想说好家伙. 从代码分析我们可以看出其实RT-Thread在初始化时钟的时候其实忽略的输入参数的,因此我们如果想要更换时钟源只需要将system_clock_config()函数改成我们需要设置的时钟源即可.
这里我推荐直接使用CubeMX生成对应的时钟初始化函数,赋值粘贴过来即可