因为速度慢下来,所有忙了,呵呵,别字,是“慢”
晶振启振 /* RCC system reset(for debug purpose) */ RCC_DeInit(); /* Enable HSE */ RCC_HSEConfig(RCC_HSE_ON); /* Wait till HSE is ready */ HSEStartUpStatus = RCC_WaitForHSEStartUp(); if(HSEStartUpStatus == SUCCESS) { /* Enable Prefetch Buffer */ FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable); /* Flash 2 wait state */ FLASH_SetLatency(FLASH_Latency_2); /* HCLK = SYSCLK */ RCC_HCLKConfig(RCC_SYSCLK_Div1); /* PCLK2 = HCLK */ RCC_PCLK2Config(RCC_HCLK_Div1); /* PCLK1 = HCLK/2 */ RCC_PCLK1Config(RCC_HCLK_Div2); /* ADCCLK = PCLK2/4 */ RCC_ADCCLKConfig(RCC_PCLK2_Div4); /* PLLCLK = 8MHz * 9 = 72 MHz */ RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_9); /* Enable PLL */ RCC_PLLCmd(ENABLE); /* Wait till PLL is ready */ while(RCC_GetFlagStatus(RCC_FLAG_PLLRDY) == RESET); /* Select PLL as system clock source */ RCC_SYSCLKConfig(RCC_SYSCLKSource_PLLCLK); /* Wait till PLL is used as system clock source */ while(RCC_GetSYSCLKSource() != 0x08); } 没有示波器,用万用表测试的, 在单步到 RCC_HSEConfig(RCC_HSE_ON);之前 晶振任意端对地电压是0.08左右, 执行完 RCC_HSEConfig(RCC_HSE_ON); 电压变为 2.0左右