mcu.之armv7 contex-M3/M4系列，时钟树，中断， cpu架构，上电启动过程（二）

上一篇讲了时钟树，本文记录上电系统设置。

一、STM32 启动

1、上电复位 → 汇编启动文件（startup_stm32f10x.s）堆栈初始化、中断向量表、进入 main 之前的最底层。

2、系统时钟初始化（SystemInit 或自己写寄存器）配置 HSE / PLL / SYSCLK / AHB / APB1 / APB2。

3、外设时钟使能 + 初始化GPIO / UART / I2C / SPI / ADC / TIM 等

在stm32f10x_rcc.h定义了很多时钟总线。

f103标准库函数版本，各个模块，时钟初始化。

c 复制代码

#include "stm32f10x.h"
#include "stm32f10x_gpio.h"
#include "stm32f10x_rcc.h"
#include "stm32f10x_usart.h"
#include "stm32f10x_i2c.h"
#include "stm32f10x_spi.h"
#include "stm32f10x_adc.h"
#include "stm32f10x_tim.h"
#include "stm32f10x_iwdg.h"
#include "stm32f10x_rtc.h"
#include "stm32f10x_pwr.h"
#include "misc.h"

// 全局变量
uint16_t adc_value = 0;

/*********************************************************************
 * 时钟初始化：72MHz (HSE=8MHz, PLL×9)
 ********************************************************************/
void RCC_Init(void)
{
    RCC_DeInit();
    RCC_HSEConfig(RCC_HSE_ON);
    RCC_WaitForHSEStartUp();

    RCC_HCLKConfig(RCC_SYSCLK_Div1);
    RCC_PCLK1Config(RCC_HCLK_Div2);   // APB1=36MHz
    RCC_PCLK2Config(RCC_HCLK_Div1);   // APB2=72MHz

    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);
}

/*********************************************************************
 * GPIO 初始化
 ********************************************************************/
void GPIO_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStruct;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC | RCC_APB2Periph_GPIOA | RCC_APB2Periph_GPIOB, ENABLE);

    // PC13 推挽输出
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_13;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOC, &GPIO_InitStruct);
}

/*********************************************************************
 * UART1 初始化 115200
 ********************************************************************/
void UART1_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStruct;
    USART_InitTypeDef USART_InitStruct;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1 | RCC_APB2Periph_GPIOA, ENABLE);

    // PA9 TX
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_9;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStruct);

    // PA10 RX
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_10;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(GPIOA, &GPIO_InitStruct);

    USART_InitStruct.USART_BaudRate = 115200;
    USART_InitStruct.USART_WordLength = USART_WordLength_8b;
    USART_InitStruct.USART_StopBits = USART_StopBits_1;
    USART_InitStruct.USART_Parity = USART_Parity_No;
    USART_InitStruct.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    USART_InitStruct.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;

    USART_Init(USART1, &USART_InitStruct);
    USART_Cmd(USART1, ENABLE);
}

/*********************************************************************
 * I2C1 初始化 100kHz
 ********************************************************************/
void I2C_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStruct;
    I2C_InitTypeDef I2C_InitStruct;

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);

    // PB6 SCL, PB7 SDA
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF_OD;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOB, &GPIO_InitStruct);

    I2C_InitStruct.I2C_ClockSpeed = 100000;
    I2C_InitStruct.I2C_Mode = I2C_Mode_I2C;
    I2C_InitStruct.I2C_DutyCycle = I2C_DutyCycle_2;
    I2C_InitStruct.I2C_OwnAddress1 = 0x00;
    I2C_InitStruct.I2C_Ack = I2C_Ack_Enable;
    I2C_InitStruct.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;

    I2C_Init(I2C1, &I2C_InitStruct);
    I2C_Cmd(I2C1, ENABLE);
}

/*********************************************************************
 * SPI1 初始化（主机）
 ********************************************************************/
void SPI_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStruct;
    SPI_InitTypeDef SPI_InitStruct;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_SPI1 | RCC_APB2Periph_GPIOA, ENABLE);

    // PA5 SCK, PA7 MOSI, PA6 MISO
    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_7;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStruct.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStruct);

    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_6;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(GPIOA, &GPIO_InitStruct);

    SPI_InitStruct.SPI_Direction = SPI_Direction_2Lines_FullDuplex;
    SPI_InitStruct.SPI_Mode = SPI_Mode_Master;
    SPI_InitStruct.SPI_DataSize = SPI_DataSize_8b;
    SPI_InitStruct.SPI_CPOL = SPI_CPOL_Low;
    SPI_InitStruct.SPI_CPHA = SPI_CPHA_1Edge;
    SPI_InitStruct.SPI_NSS = SPI_NSS_Soft;
    SPI_InitStruct.SPI_BaudRatePrescaler = SPI_BaudRatePrescaler_4;
    SPI_InitStruct.SPI_FirstBit = SPI_FirstBit_MSB;

    SPI_Init(SPI1, &SPI_InitStruct);
    SPI_Cmd(SPI1, ENABLE);
}

/*********************************************************************
 * ADC1 初始化（PA0）
 ********************************************************************/
void ADC_Init(void)
{
    ADC_InitTypeDef ADC_InitStruct;
    GPIO_InitTypeDef GPIO_InitStruct;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1 | RCC_APB2Periph_GPIOA, ENABLE);
    RCC_ADCCLKConfig(RCC_PCLK2_Div6);    // 12MHz

    GPIO_InitStruct.GPIO_Pin = GPIO_Pin_0;
    GPIO_InitStruct.GPIO_Mode = GPIO_Mode_AIN;
    GPIO_Init(GPIOA, &GPIO_InitStruct);

    ADC_InitStruct.ADC_Mode = ADC_Mode_Independent;
    ADC_InitStruct.ADC_ScanConvMode = DISABLE;
    ADC_InitStruct.ADC_ContinuousConvMode = DISABLE;
    ADC_InitStruct.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
    ADC_InitStruct.ADC_DataAlign = ADC_DataAlign_Right;
    ADC_InitStruct.ADC_NbrOfChannel = 1;

    ADC_Init(ADC1, &ADC_InitStruct);
    ADC_RegularChannelConfig(ADC1, ADC_Channel_0, 1, ADC_SampleTime_55Cycles5);

    ADC_Cmd(ADC1, ENABLE);
    ADC_ResetCalibration(ADC1);
    while(ADC_GetResetCalibrationStatus(ADC1));
    ADC_StartCalibration(ADC1);
    while(ADC_GetCalibrationStatus(ADC1));
}

/*********************************************************************
 * TIM3 中断初始化 100ms
 ********************************************************************/
void TIM3_Init(void)
{
    TIM_TimeBaseInitTypeDef TIM_InitStruct;
    NVIC_InitTypeDef NVIC_InitStruct;

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);

    TIM_InitStruct.TIM_Period = 1000 - 1;
    TIM_InitStruct.TIM_Prescaler = 7200 - 1;
    TIM_InitStruct.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_InitStruct.TIM_CounterMode = TIM_CounterMode_Up;

    TIM_TimeBaseInit(TIM3, &TIM_InitStruct);
    TIM_ITConfig(TIM3, TIM_IT_Update, ENABLE);
    TIM_Cmd(TIM3, ENABLE);

    NVIC_InitStruct.NVIC_IRQChannel = TIM3_IRQn;
    NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 1;
    NVIC_InitStruct.NVIC_IRQChannelSubPriority = 1;
    NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStruct);
}

/*********************************************************************
 * 独立看门狗 IWDG 初始化（约5秒）
 ********************************************************************/
void IWDG_Init(void)
{
    IWDG_WriteAccessCmd(IWDG_WriteAccess_Enable);
    IWDG_SetPrescaler(IWDG_Prescaler_128);
    IWDG_SetReload(0xFFF);
    IWDG_ReloadCounter();
    IWDG_Enable();
}

/*********************************************************************
 * RTC 初始化（使用 LSI）
 ********************************************************************/
void RTC_Init(void)
{
    RCC_LSICmd(ENABLE);
    while(RCC_GetFlagStatus(RCC_FLAG_LSIRDY) == RESET);

    RCC_RTCCLKConfig(RCC_RTCCLKSource_LSI);
    RCC_RTCCLKCmd(ENABLE);

    RTC_WaitForSynchro();
    RTC_WaitForLastTask();

    RTC_SetPrescaler(39999);  // 1s 中断
    RTC_WaitForLastTask();
}

/*********************************************************************
 * 主函数（你要的结构）
 ********************************************************************/
int main(void)
{
    // 1. 系统时钟
    RCC_Init();

    // 2. 初始化所有模块
    GPIO_Init();
    UART1_Init();
    I2C_Init();
    SPI_Init();
    ADC_Init();
    TIM3_Init();
    IWDG_Init();
    RTC_Init();

    while(1)
    {
        // 喂狗
        IWDG_ReloadCounter();

        // ADC 采集
        ADC_SoftwareStartConvCmd(ADC1, ENABLE);
        while(!ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC));
        adc_value = ADC_GetConversionValue(ADC1);
    }
}

/*********************************************************************
 * TIM3 中断服务函数
 ********************************************************************/
void TIM3_IRQHandler(void)
{
    if(TIM_GetITStatus(TIM3, TIM_IT_Update) != RESET)
    {
        TIM_ClearITPendingBit(TIM3, TIM_IT_Update);
        GPIO_WriteBit(GPIOC, GPIO_Pin_13, !GPIO_ReadOutputDataBit(GPIOC, GPIO_Pin_13));
    }
}

c 复制代码

int main(void)
{
    // 1. 系统时钟
    RCC_Init();

    // 2. 初始化所有模块
    GPIO_Init();
    UART1_Init();
    I2C_Init();
    SPI_Init();
    ADC_Init();
    TIM3_Init();
    IWDG_Init();
    RTC_Init();

    while(1)
    {

    }
}

f407，hal库版本

c 复制代码

#include "main.h"
#include "stm32f4xx_hal.h"

UART_HandleTypeDef huart1;
I2C_HandleTypeDef hi2c1;
SPI_HandleTypeDef hspi1;
ADC_HandleTypeDef hadc1;
TIM_HandleTypeDef htim3;
IWDG_HandleTypeDef hiwdg;
RTC_HandleTypeDef hrtc;

/*********************************************************************
 * 时钟初始化：HSE=25MHz → 系统时钟 168MHz
 ********************************************************************/
void SystemClock_Config(void)
{
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};

  __HAL_RCC_PWR_CLK_ENABLE();
  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);

  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE|RCC_OSCILLATORTYPE_LSI;
  RCC_OscInitStruct.HSEState = RCC_HSE_ON;
  RCC_OscInitStruct.LSIState = RCC_LSI_ON;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
  RCC_OscInitStruct.PLL.PLLM = 25;
  RCC_OscInitStruct.PLL.PLLN = 336;
  RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
  RCC_OscInitStruct.PLL.PLLQ = 7;
  HAL_RCC_OscConfig(&RCC_OscInitStruct);

  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_DIV4;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;
  HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_5);
}

/*********************************************************************
 * GPIO 初始化
 ********************************************************************/
void MX_GPIO_Init(void)
{
  __HAL_RCC_GPIOC_CLK_ENABLE();
  __HAL_RCC_GPIOA_CLK_ENABLE();
  __HAL_RCC_GPIOB_CLK_ENABLE();

  GPIO_InitTypeDef GPIO_InitStruct = {0};

  // PC13 输出
  GPIO_InitStruct.Pin = GPIO_PIN_13;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);
}

/*********************************************************************
 * UART1 初始化
 ********************************************************************/
void MX_USART1_UART_Init(void)
{
  huart1.Instance = USART1;
  huart1.Init.BaudRate = 115200;
  huart1.Init.WordLength = UART_WORDLENGTH_8B;
  huart1.Init.StopBits = UART_STOPBITS_1;
  huart1.Init.Parity = UART_PARITY_NONE;
  huart1.Init.Mode = UART_MODE_TX_RX;
  huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
  huart1.Init.OverSampling = UART_OVERSAMPLING_16;
  HAL_UART_Init(&huart1);
}

/*********************************************************************
 * I2C1 初始化
 ********************************************************************/
void MX_I2C1_Init(void)
{
  hi2c1.Instance = I2C1;
  hi2c1.Init.ClockSpeed = 100000;
  hi2c1.Init.DutyCycle = I2C_DUTYCYCLE_2;
  hi2c1.Init.OwnAddress1 = 0;
  hi2c1.Init.AddressingMode = I2C_ADDRESSINGMODE_7BIT;
  hi2c1.Init.DualAddressMode = I2C_DUALADDRESS_DISABLE;
  hi2c1.Init.OwnAddress2 = 0;
  hi2c1.Init.GeneralCallMode = I2C_GENERALCALL_DISABLE;
  hi2c1.Init.NoStretchMode = I2C_NOSTRETCH_DISABLE;
  HAL_I2C_Init(&hi2c1);
}

/*********************************************************************
 * SPI1 初始化
 ********************************************************************/
void MX_SPI1_Init(void)
{
  hspi1.Instance = SPI1;
  hspi1.Init.Mode = SPI_MODE_MASTER;
  hspi1.Init.Direction = SPI_DIRECTION_2LINES;
  hspi1.Init.DataSize = SPI_DATASIZE_8BIT;
  hspi1.Init.CLKPolarity = SPI_POLARITY_LOW;
  hspi1.Init.CLKPhase = SPI_PHASE_1EDGE;
  hspi1.Init.NSS = SPI_NSS_SOFT;
  hspi1.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_8;
  hspi1.Init.FirstBit = SPI_FIRSTBIT_MSB;
  HAL_SPI_Init(&hspi1);
}

/*********************************************************************
 * ADC1 初始化
 ********************************************************************/
void MX_ADC1_Init(void)
{
  ADC_ChannelConfTypeDef sConfig = {0};

  hadc1.Instance = ADC1;
  hadc1.Init.ClockPrescaler = ADC_CLOCK_SYNC_PCLK_DIV4;
  hadc1.Init.Resolution = ADC_RESOLUTION_12B;
  hadc1.Init.ScanConvMode = DISABLE;
  hadc1.Init.ContinuousConvMode = DISABLE;
  hadc1.Init.DiscontinuousConvMode = DISABLE;
  hadc1.Init.ExternalTrigConvEdge = ADC_EXTERNALTRIGCONVEDGE_NONE;
  hadc1.Init.DataAlign = ADC_DATAALIGN_RIGHT;
  hadc1.Init.NbrOfConversion = 1;
  HAL_ADC_Init(&hadc1);

  sConfig.Channel = ADC_CHANNEL_0;
  sConfig.Rank = 1;
  sConfig.SamplingTime = ADC_SAMPLETIME_3CYCLES;
  HAL_ADC_ConfigChannel(&hadc1, &sConfig);
}

/*********************************************************************
 * TIM3 中断初始化
 ********************************************************************/
void MX_TIM3_Init(void)
{
  htim3.Instance = TIM3;
  htim3.Init.Prescaler = 8400-1;
  htim3.Init.CounterMode = TIM_COUNTERMODE_UP;
  htim3.Init.Period = 1000-1;
  htim3.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
  HAL_TIM_Base_Init(&htim3);
  HAL_TIM_Base_Start_IT(&htim3);
}

/*********************************************************************
 * IWDG 看门狗
 ********************************************************************/
void MX_IWDG_Init(void)
{
  hiwdg.Instance = IWDG;
  hiwdg.Init.Prescaler = IWDG_PRESCALER_128;
  hiwdg.Init.Reload = 4095;
  HAL_IWDG_Init(&hiwdg);
}

/*********************************************************************
 * RTC 时钟
 ********************************************************************/
void MX_RTC_Init(void)
{
  hrtc.Instance = RTC;
  hrtc.Init.HourFormat = RTC_HOURFORMAT_24;
  hrtc.Init.AsynchPrediv = 127;
  hrtc.Init.SynchPrediv = 255;
  HAL_RTC_Init(&hrtc);
}

/*********************************************************************
 * 你要的 MAIN 函数（完全一样）
 ********************************************************************/
int main(void)
{
  HAL_Init();
  SystemClock_Config();

  MX_GPIO_Init();
  MX_USART1_UART_Init();
  MX_I2C1_Init();
  MX_SPI1_Init();
  MX_ADC1_Init();
  MX_TIM3_Init();
  MX_IWDG_Init();
  MX_RTC_Init();

  while (1)
  {
    HAL_IWDG_Refresh(&hiwdg);
  }
}

/*********************************************************************
 * 定时器中断回调
 ********************************************************************/
void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
  if(htim->Instance == TIM3)
  {
    HAL_GPIO_TogglePin(GPIOC, GPIO_PIN_13);
  }
}