STM32上的ADC单次转换

时间:2015-02-04 04:25:15

标签: c serial-port stm32 adc usart

我在STM32 F103x上学习ADC编程,从最简单的情况开始 - 单次转换。 测量内部温度传感器(连接到ADC1)的值,并使用USART将其发送到COM端口。目标似乎很清楚但是当我尝试将源代码下载到闪存时,它不会将任何数据发送到COM端口。 USART功能运行良好,我猜这些问题来自ADC配置部分,因为我在等待完全转换的循环中挂起:

while(ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC) == RESET); //Wail for conversion complete

到目前为止,这是我的源代码。

/* Includes ------------------------------------------------------------*/
#include "stm32f10x.h"
#include <stdio.h>

    uint16_t AD_value;
    const uint16_t V25 = 1750; //when V25=1.41V
    const uint16_t Avg_Slope = 5; //when avg_slc
    uint16_t TemperatureC;

//Define output device
PUTCHAR_PROTOTYPE
{
    USART_SendData(USART1, (uint8_t) ch);
    while (USART_GetFlagStatus(USART1, USART_FLAG_TC) == RESET)
    {}
    return ch;
}

void Usart1Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    USART_InitTypeDef USART_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1 | RCC_APB2Periph_GPIOA | RCC_APB2Periph_AFIO, ENABLE);

    /* COnfig PA9 for USART Tx as alternate function push-pull */
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    /* COnfig PA10 for USART Rx as input floating */
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    /* USARTx 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 = 9600;
    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 configuration */
    USART_Init(USART1, &USART_InitStructure);
    USART_Cmd(USART1, ENABLE);  

}

int main(void)
{

    ADC_InitTypeDef ADC_InitStructure;
    Usart1Init();

    RCC_ADCCLKConfig(RCC_PCLK2_Div6); //ADCCLK = PCLK22/6 = 72/6=12MHz
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1, ENABLE); //Enable ADC1 Clock

    /* ADC1 configuration */
    ADC_DeInit(ADC1); //Power-on default
    ADC_InitStructure.ADC_Mode = ADC_Mode_Independent; //Independent conversion mode (single)
    ADC_InitStructure.ADC_ScanConvMode = DISABLE; //Convert single channel only
    ADC_InitStructure.ADC_ContinuousConvMode = DISABLE; //Convert 1 time
    ADC_InitStructure.ADC_ExternalTrigConv = DISABLE; //No external triggering
    ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right; //Right 12-bit data alignment
    ADC_InitStructure.ADC_NbrOfChannel = 1; //single channel conversion
    ADC_Init(ADC1, &ADC_InitStructure);
    ADC_TempSensorVrefintCmd(ENABLE); //wake up temperature sensor
    ADC_Cmd(ADC1, ENABLE); //Enable ADC1
    ADC_ResetCalibration(ADC1); //Enable ADC1 reset calibration register
    while(ADC_GetResetCalibrationStatus(ADC1)); //check the end of ADC1 reset calibration register  
    ADC_StartCalibration(ADC1); //Start ADC1 calibration
    while(ADC_GetCalibrationStatus(ADC1)); //Check the end of ADC1 calibration
    ADC_RegularChannelConfig(ADC1, ADC_Channel_16, 1, ADC_SampleTime_1Cycles5); //Select 1.5 cycles conversion for channel 16
    ADC_SoftwareStartConvCmd(ADC1, ENABLE); //Start ADC1 software conversion
    while(ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC) == RESET); //Wail for conversion complete
    AD_value = ADC_GetConversionValue(ADC1); //Read ADC value
    ADC_ClearFlag(ADC1, ADC_FLAG_EOC); //Clear EOC flag

    printf("\r\n ADC value: %d \r\n", AD_value);
    TemperatureC = (uint16_t)((V25-AD_value)/Avg_Slope+25);
    printf("Temperature: %d%cC\r\n", TemperatureC, 176);
    while (1)
    {}  
}

感谢任何想法!

3 个答案:

答案 0 :(得分:5)

我将尝试解释源代码的内容。

1-禁用定义为零: typedef enum {DISABLE = 0,ENABLE =!DISABLE} FunctionalState;

2-所以当你写“ADC_InitStructure.ADC_ExternalTrigConv = DISABLE;”你实际上把它分配给零,如“ADC_InitStructure.ADC_ExternalTrigConv = 0;

3-这意味着您将ADC_CR2寄存器的EXTSEL指定为零。

4 - 如果EXTSEL为零,则adc转换取决于启动的定时器。

5 - 如果你想用软件启动adc,EXTSEL必须是0x000E0000;

6-正如你猜测的那样,“ADC_ExternalTrigConv_None”的值定义为0x000E0000;

所以 while(ADC_GetFlagStatus(ADC1,ADC_FLAG_EOC)== RESET); 代码会挂起来,因为它依赖于定时器启动,如果它没有启动它就无法结束。

答案 1 :(得分:3)

问题解决了! 禁用外部触发器是我的错。而不是使用:

ADC_InitStructure.ADC_ExternalTrigConv = DISABLE;

它应该是这样的:

ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;

多么愚蠢!

答案 2 :(得分:0)

我不会在这里发明一个轮子,因为你挂在这三个while()循环中的一个循环中。在每个之前做一些输出然后你会知道你在哪里挂。

如果你有调试器(它存在于每个ST开发板上,可能你用它来下载程序),请不要犹豫使用它:)