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我正在尝试使用 UART 在 1-Wire 上对数字温度计 DS18B20 进行编程,但遇到了奇怪的问题。当我调试这个没有断点运行的程序(或者只是运行没有调试的程序)时,我的读数约为 100°C。当我在接收温度信息之前设置断点时,它给了我大约 50°c。第三个选项当我打开这个窗口时,我可以看到 SFR 并展开 UART4 部分,它给了我大约 25°C 的正确读数。我有 Saleae 逻辑分析仪,在所有这 3 种情况下,它都会向我发送有效数据(约 25°C)。我试图在断点所在的地方设置一些延迟(甚至延迟 2 秒),但没有帮助。它给了我大约 50°C 的读数(比如断点和未扩展的 SFR 窗口)。这可能是编程错误(我要开始了),但是这个带有扩展 SFR 窗口的操作超出了我的推理范围。我真的不知道发生了什么事。我希望你能为我了解一下这种情况。

我正在使用 STM32F4-Discovery 评估板并在 Atollic 4.1.0 上对其进行编程。

我的“图书馆”文件:

#include "DS18B20_Lib.h"


void DS18B20_Init(void)
{
    //USART4 PA0
    GPIO_InitTypeDef GS;
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_UART4,ENABLE);
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA,ENABLE);
    GPIO_PinAFConfig(GPIOA,GPIO_PinSource0,GPIO_AF_UART4);

    GS.GPIO_Mode = GPIO_Mode_AF;
    GS.GPIO_OType = GPIO_OType_PP;
    GS.GPIO_PuPd = GPIO_PuPd_UP;
    GS.GPIO_Speed = GPIO_Speed_50MHz;
    GS.GPIO_Pin = GPIO_Pin_0;
    GPIO_Init(GPIOA,&GS);

    USART_InitTypeDef US;
    US.USART_BaudRate = 115200;
    US.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    US.USART_Mode = USART_Mode_Tx | USART_Mode_Rx;
    US.USART_Parity = USART_Parity_No;
    US.USART_StopBits = USART_StopBits_1;
    US.USART_WordLength = USART_WordLength_8b;
    USART_Init(UART4,&US);
    USART_SetAddress(UART4,0x12);
    USART_Cmd(UART4,ENABLE);
    USART_HalfDuplexCmd(UART4,ENABLE);

    USART_ITConfig(UART4,USART_IT_TXE | USART_IT_RXNE | USART_IT_TC ,ENABLE);
    /*NVIC_InitTypeDef NS;
    NS.NVIC_IRQChannel = UART4_IRQn;
    NS.NVIC_IRQChannelCmd = ENABLE;
    NS.NVIC_IRQChannelPreemptionPriority = 1;
    NS.NVIC_IRQChannelSubPriority = 1;
    NVIC_Init(&NS);*/

}

uint16_t Reset_1Wire(void)
{
    uint16_t Present;
    while (USART_GetFlagStatus(UART4, USART_FLAG_TC) == RESET);
    UART4->BRR = 0x1117;
    while (USART_GetFlagStatus(UART4, USART_FLAG_TXE) == RESET);
    USART_SendData(UART4,0xF0);
    while (USART_GetFlagStatus(UART4, USART_FLAG_RXNE) == RESET);
    Present = USART_ReceiveData(UART4);
    while (USART_GetFlagStatus(UART4, USART_FLAG_TC) == RESET);
    UART4->BRR = 0x016D;
    return Present;
}

char Read_1Wire(void)
{

    char Data=0;
    int i;
    for(i=0;i<8;i++)
    {
        while (USART_GetFlagStatus(UART4, USART_FLAG_TXE) == RESET);
        USART_SendData(UART4,0xFF);
        while (USART_GetFlagStatus(UART4, USART_FLAG_RXNE) == RESET);
        if(USART_ReceiveData(UART4)==0xFF)
            Data|=0x80;
        else Data|=0;
        if (i!=7) Data=Data>>1;
    }
    return Data;
}

void Write_1Wire(char Data)
{
    char Mask=1;
    int i;
    for(i=0;i<8;i++)
    {
        while (USART_GetFlagStatus(UART4, USART_FLAG_TXE) == RESET);
        if (Data & Mask)
            USART_SendData(UART4,0xFF);
        else
            USART_SendData(UART4,0x00);
        Mask=Mask<<1;
    }
}

uint16_t DS18B20_MeasTemp(void)
{
    uint16_t Data;
    uint16_t LSB;
    uint16_t MSB;
    Reset_1Wire();
    Write_1Wire(0xCC); //SkipRom only 1 device
    Write_1Wire(0x44);
    while(Read_1Wire()==0x00);
    Reset_1Wire();
    Write_1Wire(0xCC);
    Write_1Wire(0xBE);
   /*--------BRAKEPOINT HERE--------*/
    LSB=Read_1Wire();
    MSB=Read_1Wire();
    Data=MSB<<8|LSB;
    Reset_1Wire();
    return Data;
}

我的主要功能:

int main(void)
{
  char strLine[25];
  uint16_t Temperature;

  LCD_Init();
  LCD_SetColors(GREEN, BLUE);
  LCD_Clear(BLUE);
  LCD_CharSize(16);

  DS18B20_Init();

  sprintf(strLine,"%s","Temp: ");
  LCD_StringLine(20,50,(uint8_t*) strLine);
  //GPIO_Config();
  while (1)
  {
    Presence1Wire();
    Temperature = DS18B20_MeasTemp();
    if (Temperature&0xF000)
        LCD_PutChar(60,50,'-');
    else LCD_PutChar(60,50,'+');
    LCD_PutInt(68,50,(Temperature&0x0FF0)>>4);
    LCD_PutInt(72,64,(Temperature&0xF)*625);
  }

}
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2 回答 2

0
Write_1Wire(0xCC);
Write_1Wire(0xBE);
  • 向 UART 发送字节并且不读取。在fifo中接收数据。
Read_1Wire()
  • 在 fifo 中读取旧数据。
uint16_t DS18B20_MeasTemp(void)
{
    uint16_t Data;
    uint16_t LSB;
    uint16_t MSB;
    Reset_1Wire();
    Write_1Wire(0xCC); //SkipRom only 1 device
    Write_1Wire(0x44);
    while(Read_1Wire() == 0x00);
    Reset_1Wire();
    Write_1Wire(0xCC);
    Write_1Wire(0xBE);
   /*--------BRAKEPOINT HERE--------*/
    // !!!!!!! Paste this
    while (USART_GetFlagStatus(UART4, USART_FLAG_RXNE) != RESET)
      USART_ReceiveData(UART4);
    // !!!!!!!
    LSB = Read_1Wire();
    MSB = Read_1Wire();
    Data = MSB << 8 | LSB;
    Reset_1Wire();
    return Data;
}
于 2014-09-20T03:40:54.440 回答
0

I've also encountered a similar problem, I was measuring capacitance of a capacitance water level sensor and while running in debugging I got different values than in run mode without the usage of debugger (just plainly connecting it to an external power supply).

I think the issue is with the architecture of the processor, when you are debugging the breakpoint it pauses the cpu but not the peripheral clocks, and GPT aren't getting paused which gives different readings since my measurements are timer dependent.

I'm speaking from my perspective so it might not be happening in your case but it could give you a different view to the problem.

于 2019-04-30T05:26:43.620 回答