通过中断方式读取电压,不过最后楼主读取参考电压失败,还没有找到错误,所以读取的电压只能十六进制显示,
本文的介绍按照一般流程来走:
1,串口的初始化
2,ADC初始化
3,中断初始化
4,编写中断函数
5,编写主函数
接下来详细介绍:
1,串口的初始化:
- void usart_init()
- {
- GPIO_InitTypeDef Uart_A;
-
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA ,ENABLE);
- Uart_A.GPIO_Pin = GPIO_Pin_9;
- Uart_A.GPIO_Speed = GPIO_Speed_50MHz;
- Uart_A.GPIO_Mode = GPIO_Mode_AF_PP;
- GPIO_Init(GPIOA,&Uart_A);
-
- Uart_A.GPIO_Pin = GPIO_Pin_10;
- Uart_A.GPIO_Speed = GPIO_Speed_50MHz;
- Uart_A.GPIO_Mode = GPIO_Mode_IN_FLOATING;
- GPIO_Init(GPIOA,&Uart_A);
-
- USART_InitTypeDef Uart;
-
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1,ENABLE);
- Uart.USART_BaudRate = 115200;
- Uart.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
- Uart.USART_Mode = USART_Mode_Tx;
- Uart.USART_Parity = USART_Parity_No;
- Uart.USART_StopBits = USART_StopBits_1;
- Uart.USART_WordLength = USART_WordLength_8b;
- USART_Init(USART1,&Uart);
-
- USART_Cmd(USART1,ENABLE);
- USART_ClearFlag(USART1,USART_FLAG_TC);
- }
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关于本段代码,我前面写的文章STM32基础设计(3)有详细讲解,此处不再赘述。
2,ADC初始化
- typedef struct
- {//配置ADC的模式,一个ADC是独立模式,2个是双模式
- uint32_t ADC_Mode; /*!< Configures the ADC to operate in independent or
- dual mode.
- This parameter can be a value of @ref ADC_mode */
- //配置ADC是否使用扫描,单通道不扫描,多通道扫描
- FunctionalState ADC_ScanConvMode; /*!< Specifies whether the conversion is performed in
- Scan (multichannels) or Single (one channel) mode.
- This parameter can be set to ENABLE or DISABLE */
- //配置ADC是单次转换还是连续转换
- FunctionalState ADC_ContinuousConvMode; /*!< Specifies whether the conversion is performed in
- Continuous or Single mode.
- This parameter can be set to ENABLE or DISABLE. */
- //外部触发选择
- uint32_t ADC_ExternalTrigConv; /*!< Defines the external trigger used to start the analog
- to digital conversion of regular channels. This parameter
- can be a value of @ref ADC_external_trigger_sources_for_regular_channels_conversion */
- //转换结果数据对其方式
- uint32_t ADC_DataAlign; /*!< Specifies whether the ADC data alignment is left or right.
- This parameter can be a value of @ref ADC_data_align */
- //ADC转换的通道数目
- uint8_t ADC_NbrOfChannel; /*!< Specifies the number of ADC channels that will be converted
- using the sequencer for regular channel group.
- This parameter must range from 1 to 16. */
- }ADC_InitTypeDef;
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下面粘贴代码:
- void Adc_Init()
- {
- ADC_InitTypeDef adc;//定义ADC结构的变量
- GPIO_InitTypeDef io_b;//定义串口结构体变量 ,开发板上的电源接的是GPIOB端口的 1引脚,查数据手册,其为ADC1的9通道
-
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1 | RCC_APB2Periph_GPIOB,ENABLE);//开时钟(即把心脏激活)
- RCC_ADCCLKConfig(RCC_PCLK2_Div6);
-
- io_b.GPIO_Pin = GPIO_Pin_1;//设置端口引脚为 引脚1
- io_b.GPIO_Mode = GPIO_Mode_AIN;//设置为输入模式
- io_b.GPIO_Speed = GPIO_Speed_50MHz;//最高速率为50MHz
- GPIO_Init(GPIOB,&io_b);初始化引脚
- ADC_DeInit(ADC1);先将外设ADC1的全部寄存器重设为默认值 ADC_TempSensorVrefintCmd(ENABLE);谁能外部参照电压(勿忘)
- adc.ADC_Mode = ADC_Mode_Independent;设置ADC为独立模式
- adc.ADC_ScanConvMode = ENABLE;使能扫描模式
- adc.ADC_ContinuousConvMode = ENABLE;使能连续扫描
- adc.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;不使用外部触发
- adc.ADC_DataAlign = ADC_DataAlign_Right;数据右对齐
- adc.ADC_NbrOfChannel = 2;来制定用几个ADC通达(勿忘)
- ADC_Init(ADC1,&adc);初始化ADC寄存器
-
- ADC_RegularChannelConfig(ADC1,ADC_Channel_9,1,ADC_SampleTime_239Cycles5);制定用哪个ADC转换、第几个通道,转换的顺序、转换的周期
- ADC_RegularChannelConfig(ADC1,ADC_Channel_17,2,ADC_SampleTime_239Cycles5);
- //这里需要根据数据手册来设定通道,数据手册上会说明那个引脚对应那个通道,外接电源接到那个引脚上就可以了,必须按照数据手册的要求来,不然肯定会出错,博主在这里就有一个很大很大的教训,望读者谨记
- ADC_ITConfig(ADC1,ADC_IT_EOC,ENABLE);打开ADC中断
- ADC_Cmd(ADC1,ENABLE);使能ADC1
- ADC_ResetCalibration(ADC1);复位ADC1的校准寄存器
- while(ADC_GetResetCalibrationStatus(ADC1));等待校准寄存器复位完成
-
- ADC_StartCalibration(ADC1);开始ADC1校准
- while(ADC_GetCalibrationStatus(ADC1));等待ADC1校准完成
- ADC_SoftwareStartConvCmd(ADC1,ENABLE);使能指定的ADC1的软件转换启动功能
- }
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3.中断初始化
- void adc_nvic_init()
- {
-
- NVIC_InitTypeDef nvic;定义中断结构体
- NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);设置中断分组
- nvic.NVIC_IRQChannel = ADC1_2_IRQn;制定专断通道
- nvic.NVIC_IRQChannelCmd = ENABLE;使能中断
- nvic.NVIC_IRQChannelPreemptionPriority = 1;抢占优先级
- nvic.NVIC_IRQChannelSubPriority = 1;子优先级
- NVIC_Init(&nvic);初始化
-
- NVIC_InitTypeDef usart1;定义中断结构体
- NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);设置中断分组
- usart1.NVIC_IRQChannel = USART1_IRQn;指定中断通道
- usart1.NVIC_IRQChannelCmd = ENABLE;设能中断通道
- usart1.NVIC_IRQChannelPreemptionPriority = 0;抢占优先级
- usart1.NVIC_IRQChannelSubPriority= 0;子优先级
- NVIC_Init(&usart1);中断初始化
- }
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4,编写中断函数
先粘贴代码:
- void ADC1_2_IRQHandler()
- {
- if(ADC_GetITStatus(ADC1,ADC_IT_EOC) == SET)这里使用来判断,如果已经转换完成EOC位为1,具体请查看参考手册ADC状态寄存器ADC_SR的eEOC位
- {if(count_1%2 == 0){代码中的if语句中的嵌套if语句是用来区分外接电源电压和内部参考电压的。具体见下面的解释
- ADC_ConvertedValue = ADC_GetConversionValue(ADC1);
- count_1++;
- }else
- {
- ADC_ConvertedValue_1 = ADC_GetConversionValue(ADC1);
- //ADC_ConvertedValue_1 = ADC1->DR;
- count_1++;
- }
- }
- ADC_ClearITPendingBit(ADC1,ADC_IT_EOC);
- }
-
- void USART1_IRQHandler(void)
- {
- if(USART_GetFlagStatus(USART1,USART_FLAG_TXE))判断是否可以发送数据
- {
- USART1->CR1 &= ~USART_CR1_TXEIE;在这里笔者也碰到了问题,详见下文
- USART1->DR = car;
- while(USART_GetFlagStatus(USART1,USART_FLAG_TXE) == RESET);
- //USART1->CR1 &= ~USART_CR1_TXEIE;
- }
-
- if(USART1->SR & USART_SR_RXNE)判断是否可以接收数据
- {
- volatile int8_t com_data;
- com_data = USART1->DR;
- }
- }
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在ADC中断服务函数中,代码中的if语句中的嵌套if语句是用来区分外接电源电压和内部参考电压的,因为第一次接受的是外部电源电压,第二次接受的是内部参考电压,所以可以利用奇偶数,即偶数用ADC_ConvertedValue来存放外部电源电压值,奇数时用ADC_ConvertedValue_1来存放参考电压值。但是,笔者发现,这样会失败,经过串口调试发现两次接受到的值都一样,笔者初步认为,可能是ADC的转换速率太快了,具体什么歌情况还不清楚,等下一个基础设计ADC转换(DMA方式)的时候在细究。
关于那个还要在中断服务函数中再次将TXEIE设置为零,是因为发送中断是通过 打开中断函数(USART_ITConfig)进入的,该函数中已经将CR1寄存器中的TXEIE位置1 的,所以中断服务函数中还要再次清0,以防止再中断。
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5,编写主函数
- int main()
- {
- void PrintU16(uint16_t num);
- void PrintHexU8(uint8_t data);
-
- Adc_Init();
- adc_nvic_init();
- usart_init();
- while(1)
- {
- num = (uint16_t)(2.0f* ADC_ConvertedValue/ADC_ConvertedValue_1 *1.2f*100 );参考电压是1.2f通过比例关系算出实际电压。
- PrintU16(num);
- delay(1000);
- }
- }
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笔者并没有计算出准确的电压值,只是采集到两个电压值,笔者猜测,可能是因为ADC的转换速率太快,导致笔者的 通过奇偶数来区分内部电压和外部电压不管用了,笔者还在思考解决方式,如果读者有好的方法,请指教。
本文到此结束,下面是完整代码:
- #include<stm32f10x.h>
- #define uint unsigned int
- #define uchar unsigned char
-
- char car;
- static char count_1=0;//当做奇偶数
- uint16_t ADC_ConvertedValue;//存放电源电压
- uint16_t ADC_ConvertedValue_1;//存放内部参照电压
- static uint16_t num=0;
- void delay(uint n)
- {
- int i,j;
- for(i=0;i<n;i++)
- for(j=0;j<8500;j++);
- }
-
- void Adc_Init()
- {
- ADC_InitTypeDef adc;
- GPIO_InitTypeDef io_b;
-
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1 | RCC_APB2Periph_GPIOB,ENABLE);
- RCC_ADCCLKConfig(RCC_PCLK2_Div6);
-
- io_b.GPIO_Pin = GPIO_Pin_1;
- io_b.GPIO_Mode = GPIO_Mode_AIN;
- io_b.GPIO_Speed = GPIO_Speed_50MHz;
- GPIO_Init(GPIOB,&io_b);
-
- ADC_DeInit(ADC1);
- ADC_TempSensorVrefintCmd(ENABLE);
- adc.ADC_Mode = ADC_Mode_Independent;
- adc.ADC_ScanConvMode = ENABLE;
- adc.ADC_ContinuousConvMode = ENABLE;
- adc.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
- adc.ADC_DataAlign = ADC_DataAlign_Right;
- adc.ADC_NbrOfChannel = 2;
- ADC_Init(ADC1,&adc);
-
- ADC_RegularChannelConfig(ADC1,ADC_Channel_9,1,ADC_SampleTime_239Cycles5);
- ADC_RegularChannelConfig(ADC1,ADC_Channel_17,2,ADC_SampleTime_239Cycles5);
-
- ADC_ITConfig(ADC1,ADC_IT_EOC,ENABLE);
- ADC_Cmd(ADC1,ENABLE);
- ADC_ResetCalibration(ADC1);
- while(ADC_GetResetCalibrationStatus(ADC1));
-
- ADC_StartCalibration(ADC1);
- while(ADC_GetCalibrationStatus(ADC1));
- ADC_SoftwareStartConvCmd(ADC1,ENABLE);
- }
-
- void adc_nvic_init()
- {
-
- NVIC_InitTypeDef nvic;
- NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
- nvic.NVIC_IRQChannel = ADC1_2_IRQn;
- nvic.NVIC_IRQChannelCmd = ENABLE;
- nvic.NVIC_IRQChannelPreemptionPriority = 1;
- nvic.NVIC_IRQChannelSubPriority = 1;
- NVIC_Init(&nvic);
-
- NVIC_InitTypeDef usart1;
- NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
- usart1.NVIC_IRQChannel = USART1_IRQn;
- usart1.NVIC_IRQChannelCmd = ENABLE;
- usart1.NVIC_IRQChannelPreemptionPriority = 0;
- usart1.NVIC_IRQChannelSubPriority= 0;
- NVIC_Init(&usart1);
- }
-
- void usart_init()
- {
- GPIO_InitTypeDef Uart_A;
-
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA ,ENABLE);
- Uart_A.GPIO_Pin = GPIO_Pin_9;
- Uart_A.GPIO_Speed = GPIO_Speed_50MHz;
- Uart_A.GPIO_Mode = GPIO_Mode_AF_PP;
- GPIO_Init(GPIOA,&Uart_A);
-
- Uart_A.GPIO_Pin = GPIO_Pin_10;
- Uart_A.GPIO_Speed = GPIO_Speed_50MHz;
- Uart_A.GPIO_Mode = GPIO_Mode_IN_FLOATING;
- GPIO_Init(GPIOA,&Uart_A);
-
- USART_InitTypeDef Uart;
-
- RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1,ENABLE);
- Uart.USART_BaudRate = 115200;
- Uart.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
- Uart.USART_Mode = USART_Mode_Tx;
- Uart.USART_Parity = USART_Parity_No;
- Uart.USART_StopBits = USART_StopBits_1;
- Uart.USART_WordLength = USART_WordLength_8b;
- USART_Init(USART1,&Uart);
-
- USART_Cmd(USART1,ENABLE);
- USART_ClearFlag(USART1,USART_FLAG_TC);
- }
- int main()
- {
- void PrintU16(uint16_t num);
- void PrintHexU8(uint8_t data);
-
- Adc_Init();
- adc_nvic_init();
- usart_init();
- while(1)
- {
- num = (uint16_t)(2.0f* ADC_ConvertedValue/ADC_ConvertedValue_1 *1.2f*100 );
-
- PrintU16(num);
- delay(1000);
- }
- }
-
- void PrintU16(uint16_t num)
- {
- void PrintHexU8(uint8_t data);
- uint8_t w5,w4,w3,w2,w1;
- w5 = num % 100000/10000;
- w4 = num % 10000/1000;
- w3 = num % 1000/100;
- w2 = num % 100/10;
- w1 = num % 10;
- PrintHexU8('0' + w5);
- PrintHexU8('0' + w4);
- PrintHexU8('0' + w3);
- PrintHexU8('0' + w2);
- PrintHexU8('0' + w1);
- }
-
- void PrintHexU8(uint8_t data)
- {
- car = data;
- if(!(USART1->CR1 & USART_CR1_TXEIE))
- USART_ITConfig(USART1,USART_IT_TXE,ENABLE);//打开发送中断
- }
-
- void ADC1_2_IRQHandler()
- {
- if(ADC_GetITStatus(ADC1,ADC_IT_EOC) == SET)
- {if(count_1%2 == 0){
- ADC_ConvertedValue = ADC_GetConversionValue(ADC1);
- count_1++;
- }else
- {
- ADC_ConvertedValue_1 = ADC_GetConversionValue(ADC1);
- count_1++;
- }
- }
- ADC_ClearITPendingBit(ADC1,ADC_IT_EOC);
- }
-
- void USART1_IRQHandler(void)
- {
- if(USART_GetFlagStatus(USART1,USART_FLAG_TXE))
- {
- USART1->CR1 &= ~USART_CR1_TXEIE;
- USART1->DR = car;
- while(USART_GetFlagStatus(USART1,USART_FLAG_TXE) == RESET);
- //USART1->CR1 &= ~USART_CR1_TXEIE;
- }
-
- if(USART1->SR & USART_SR_RXNE)
- {
- volatile int8_t com_data;
- com_data = USART1->DR;
- }
- }
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