STM32如何通过内部VREF得到实际的VDDA值 -

/****************************************************/
// 程序用途：用来测试通过内部基准电压计算外部VDDA的值
// 程序作者：孟瑞生
// 微信公众号：科技老顽童
/****************************************************/
#include "stm32f0xx.h"
#include "stdio.h"
__IO uint16_t VREFINT_CAL;
__IO uint16_t VREFINT_DATA;
__IO float VDDA_VAL;
// 下面三个延时函数,是用示波器试出来的,非精确延时(48MHz)
void delay_1us(void)
{
volatile uint16_t i=1;
while(i--);
}
void delay_us(uint16_t us)
{
while(us--)
{
delay_1us();
}
}
void delay_ms(uint16_t ms)
{
while(ms--)
{
delay_us(995);
}
}
/**
* @brief ADC Configuration
* @param None
* @retval None
*/
static void ADC_Config(void)
{
ADC_InitTypeDef ADC_InitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
/* GPIOC Periph clock enable */
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
/* ADC1 Periph clock enable */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE);
/* Configure ADC Channel 0 as analog input */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AN;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL ;
GPIO_Init(GPIOA, &GPIO_InitStructure);
/* ADCs DeInit */
ADC_DeInit(ADC1);
/* Initialize ADC structure */
ADC_StructInit(&ADC_InitStructure);
ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
ADC_Init(ADC1, &ADC_InitStructure);
/* Convert the ADC1 Channel 0 with 239.5 Cycles as sampling time */
ADC_ChannelConfig(ADC1, ADC_Channel_Vrefint , ADC_SampleTime_239_5Cycles);
ADC_VrefintCmd(ENABLE);
/* 得到基准电压校准值 */
VREFINT_CAL = *(__IO uint16_t *)(0X1FFFF7BA);
/* ADC Calibration */
ADC_GetCalibrationFactor(ADC1);
/* Enable the ADC peripheral */
ADC_Cmd(ADC1, ENABLE);
/* Wait the ADRDY flag */
while(!ADC_GetFlagStatus(ADC1, ADC_FLAG_ADRDY));
/* ADC1 regular Software Start Conv */
ADC_StartOfConversion(ADC1);
}
/**
* @brief UART1 Configuration
* @param None
* @retval None
*/
void UART1_Init()
{
GPIO_InitTypeDef GPIO_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
USART_InitTypeDef USART_InitStructure;
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
/* Enable USART1 Clock */
RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);
/* USART1 Pins configuration ************************************************/
/* Connect pin to Periph */
GPIO_PinAFConfig(GPIOA, GPIO_PinSource9, GPIO_AF_1);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource10, GPIO_AF_1);
/* Configure pins as AF pushpull */
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9 | GPIO_Pin_10;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
GPIO_Init(GPIOA, &GPIO_InitStructure);
/* USART1 IRQ Channel configuration */
NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPriority = 0x01;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
/* USART1 configured as follow:
- BaudRate = 9600 baud
- Word Length = 8 Bits
- One Stop Bit
- No parity
- Hardware flow control disabled (RTS and CTS signals)
- Receive and transmit enabled
*/
USART_InitStructure.USART_BaudRate = 115200;
USART_InitStructure.USART_WordLength = USART_WordLength_8b;
USART_InitStructure.USART_StopBits = USART_StopBits_1;
USART_InitStructure.USART_Parity = USART_Parity_No;
USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
USART_Init(USART1, &USART_InitStructure);
/* Enable the USART1 */
USART_Cmd(USART1, ENABLE);
}
int fputc(int ch, FILE *f)
{
/* Place your implementation of fputc here */
/* e.g. write a character to the USART */
USART_SendData(USART1, (uint8_t) ch);
/* Loop until transmit data register is empty */
while (USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);
return ch;
}
// 主函数
int main(void)
{
delay_ms(200);
ADC_Config();
UART1_Init();
while(1)
{
VREFINT_DATA =ADC_GetConversionValue(ADC1);
VDDA_VAL = (3.3*VREFINT_CAL)/VREFINT_DATA;
printf("\n\rVDDA:%.3fV\n\r",VDDA_VAL);
while (USART_GetFlagStatus(USART1, USART_FLAG_TC) == RESET);
delay_ms(1000);
}
}

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