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Change STM32F103 Frequency at run time

Question asked by kk on Feb 17, 2017
Latest reply on Feb 17, 2017 by kk



I am using STM32F103. I have configured my clock at 72 MHz as shown in the below code--


RCC_DeInit(); msDelay(10); RCC_HSEConfig(RCC_HSE_OFF); msDelay(10); RCC_HSEConfig(RCC_HSE_ON); while(1){ HSEStartUpStatus = RCC_WaitForHSEStartUp(); if(HSEStartUpStatus == SUCCESS) break; } if(HSEStartUpStatus == SUCCESS) { RCC_PLLCmd(DISABLE); RCC_HCLKConfig(RCC_SYSCLK_Div1); RCC_PCLK2Config(RCC_HCLK_Div1); RCC_PCLK1Config(RCC_HCLK_Div2); FLASH_SetLatency(FLASH_Latency_2); FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable); if(HSE_VALUE==16000000){ RCC_PLLConfig(RCC_PLLSource_HSE_Div2,RCC_PLLMul_9); } else{ RCC_PLLConfig(RCC_PLLSource_HSE_Div1,RCC_PLLMul_9); } RCC_PLLCmd(ENABLE); while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET){} RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK); while(RCC_GetSYSCLKSource() != 0x08){} Flag_SYS_SPEED_72=SET; Flag_HSE_Active=SET; } else { RCC_HSIConfiguration(); Flag_HSI_Active=SET; }


Now I want to reconfigure my system clock at run time. I want to run my system at 8MHz. Please suggest how to do this.