如果被ADC转换的模拟电压低于低阀值或高于高阀值，AWD模拟看门狗状态位被设置。这些阀值位于在ADC_HTR和ADC_LTR寄存器的最低12个有效位中。通过设置ADC_CR1寄存器的AWDIE位以允许产生相应中断。
阀值独立于由ADC_CR2寄存器上的ALIGN位选择的数据对齐模式。比较是在对齐之前完成的(见10.5节)。
通过配置ADC_CR1寄存器，模拟看门狗可以作用于1个或多个通道。
ADC有一个内置自校准模式。校准可大幅减小因内部电容器组的变化而造成的准精度误差。在校准期间，每个电容器上都会计算出一个误差修正码(数字值)，这个码用于消除在随后的转换中每个电容器上产生的误差。
本例展示了如何使用ADC模拟看门狗来持续监视一个ADC通道。
设置ADC持续对通道10的模拟输入进行转换。设置模拟看门狗监视一个单独的规则通道。
一旦通道10上的输入超过模拟看门狗上限（0x0B00）或者低于下限（0x0300），就产生一个AWD中断，翻转PC.06的状态，点亮与之相连的LED。通道上的输入不回复到正常范围，这个LED就不会熄灭。
/* Includes ------------------------------------------------------------------*/
#include "stm32f10x_lib.h"
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
ADC_InitTypeDef ADC_InitStructure;
ErrorStatus HSEStartUpStatus;
/* Private function prototypes -----------------------------------------------*/
void RCC_Configuration(void);
void GPIO_Configuration(void);
void NVIC_Configuration(void);
/* Private functions ---------------------------------------------------------*/
/*******************************************************************************
* Function Name : main
* Description : Main program
* Input : None
* Output : None
* Return : None
*******************************************************************************/
int main(void)
{
#ifdef DEBUG
debug();
#endif
/* System clocks configuration ---------------------------------------------*/
RCC_Configuration();
/* NVIC configuration ------------------------------------------------------*/
NVIC_Configuration();
/* GPIO configuration ------------------------------------------------------*/
GPIO_Configuration();
/* ADC1 Configuration ------------------------------------------------------*/
ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;
ADC_InitStructure.ADC_ScanConvMode = DISABLE;
ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
ADC_InitStructure.ADC_NbrOfChannel = 1;
ADC_Init(ADC1, &ADC_InitStructure);
/* ADC1 regular channel10 configuration */
ADC_RegularChannelConfig(ADC1, ADC_Channel_10, 1, ADC_SampleTime_13Cycles5);
/* Configure high and low analog watchdog thresholds */
ADC_AnalogWatchdogThresholdsConfig(ADC1, 0x0B00, 0x0300);
//设置看门狗的上下限
/* Configure channel10 as the single analog watchdog guarded channel */
ADC_AnalogWatchdogSingleChannelConfig(ADC1, ADC_Channel_10);
//对ADC通道10设置模拟看门狗
/* Enable analog watchdog on one regular channel */
ADC_AnalogWatchdogCmd(ADC1, ADC_AnalogWatchdog_SingleRegEnable);
使能channel10规则组通道上的模拟看门狗
/* Enable AWD interupt */
ADC_ITConfig(ADC1, ADC_IT_AWD, ENABLE);
//使能AWDOG中断屏蔽
/* Enable ADC1 */
ADC_Cmd(ADC1, ENABLE);
/* Enable ADC1 reset calibaration register */ //校准
ADC_ResetCalibration(ADC1);
/* Check the end of ADC1 reset calibration register */
while(ADC_GetResetCalibrationStatus(ADC1));
/* Start ADC1 calibaration */
ADC_StartCalibration(ADC1);
/* Check the end of ADC1 calibration */
while(ADC_GetCalibrationStatus(ADC1));
/* Start ADC1 Software Conversion */
ADC_SoftwareStartConvCmd(ADC1, ENABLE);
while(1)
{
}
}
/*******************************************************************************
* Function Name : RCC_Configuration
* Description : Configures the different system clocks.
* Input : None
* Output : None
* Return : None
*******************************************************************************/
void RCC_Configuration(void)
{
/* 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)
{
/* 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);
/* Flash 2 wait state */
FLASH_SetLatency(FLASH_Latency_2);
/* Enable Prefetch Buffer */
FLASH_PrefetchBufferCmd(FLASH_PrefetchBuffer_Enable);
/* PLLCLK = 8MHz * 7 = 56 MHz */
RCC_PLLConfig(RCC_PLLSource_HSE_Div1, RCC_PLLMul_7);
/* 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)
{
}
}
/* Enable peripheral clocks --------------------------------------------------*/
/* Enable ADC1 and GPIOC clock */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1 | RCC_APB2Periph_GPIOC, ENABLE);
}
/*******************************************************************************
* Function Name : GPIO_Configuration
* Description : Configures the different GPIO ports.
* Input : None
* Output : None
* Return : None
*******************************************************************************/
void GPIO_Configuration(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
/* Configure PC.06 as output push-pull -------------------------------------*/
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
GPIO_Init(GPIOC, &GPIO_InitStructure);
/* Configure PC.00 (ADC Channel10) as analog input -------------------------*/
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
GPIO_Init(GPIOC, &GPIO_InitStructure);
}
/*******************************************************************************
* Function Name : NVIC_Configuration
* Description : Configures NVIC and Vector Table base location.
* Input : None
* Output : None
* Return : None
*******************************************************************************/
void NVIC_Configuration(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
#ifdef VECT_TAB_RAM
/* Set the Vector Table base location at 0x20000000 */
NVIC_SetVectorTable(NVIC_VectTab_RAM, 0x0);
#else /* VECT_TAB_FLASH */
/* Set the Vector Table base location at 0x08000000 */
NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x0);
#endif
/* Configure and enable ADC interrupt */
NVIC_InitStructure.NVIC_IRQChannel = ADC_IRQChannel;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
#ifdef DEBUG
/*******************************************************************************
* Function Name : assert_failed
* Description : Reports the name of the source file and the source line number
* where the assert error has occurred.
* Input : - file: pointer to the source file name
* - line: assert error line source number
* Output : None
* Return : None
*******************************************************************************/
void assert_failed(u8* file, u32 line)
{
/* User can add his own implementation to report the file name and line number,
ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
/* Infinite loop */
while (1)
{
}
}
#endif
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