1、【1】打开Keil uVision5软件，并创建相应的工程。【2】添加头文件和相依的库。
2、编写主函数获取系统时钟频率。RCC_ClocksTypeDef RCC_CLK挢旗扦渌;int main(void){ vSystem_Init(); RCC_GetClocksFreq(&RCC_CLK);//Get chip frequencies #if ( USE_SEGGER_RTT_ENABLE > 0 )//Use segger rtt enable SEGGER_RTT_printf(0, "System Clock Source : %d\r\n", RCC_GetSYSCLKSource()); SEGGER_RTT_printf(0, "APB1/PCLK1 : %dHZ\r\n", RCC_CLK.PCLK1_Frequency); SEGGER_RTT_printf(0, "APB2/PCLK2 : %dHZ\r\n", RCC_CLK.PCLK2_Frequency); SEGGER_RTT_printf(0, "SYSCLK : %dHZ\r\n", RCC_CLK.SYSCLK_Frequency); SEGGER_RTT_printf(0, "HCLK : %dHZ\r\n", RCC_CLK.HCLK_Frequency); #endif while(1) { vKeyBoard_Service_Handle(); PAout(6) = 0; vDelay_ms(100); PAout(6) = 1; vDelay_ms(1000); }}
3、使用J-Link RTT和在线调试打印显示结果00> Build Times: Mar 14 2020 08:57:4600> STM32F103xx Start Running......00>00> System Clock Source : 800> APB1/PCLK1Â : 64000000HZ00> APB2/PCLK2Â : 64000000HZ00> SYSCLK : 64000000HZ00> HCLK : 64000000HZ
4、RCC_GetSYSCLKSource()获取系统时钟源的来源。0x00 : HSI used as system clock0x04 : HSE used as system clock0x08 : PLL used as system clock
