2014-03-05 88 views
1

我试图在1-Wire上使用UART编程数字温度计DS18B20,并且出现了奇怪的问题。当我调试没有断点运行的程序时(或者只是在没有调试的情况下运行程序),我读取的温度约为100°C。当我在接收温度信息之前放置断点时,它会给我大约50°c。第三种选择是,当我看到SFR并扩展UART4部分时,只需打开此窗口,就可以获得25°C左右的正确读数。我有Saleae逻辑分析仪,在所有这3种情况下,它向我发送有效数据(约25°C)。我试图把一些延迟放在断点(甚至延迟2秒)的地方,但它并没有帮助。它给我的读数大约为50°C(就像断点和不扩展的SFR窗口一样)。这可能是编程错误(我开始),但是这种扩展了SFR窗口的操作超出了我的推理。 我真的不知道发生了什么事。我希望你能为我阐明这种情况。STM32在调试时出现了不同的结果

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

我的 “库” 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; 
} 

而我的主要功能:

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); 
    } 

} 
+0

之前从未使用STM,但是在它们的[参考手册]寻找(http://www.st.com/web/en/resource/technical/document/reference_manual/DM00031020.pdf )它看起来像GPIO需要开漏+拉起;你的代码意味着它被设置为推挽。我认为你需要'GPIO_OType_OD',但是我找不到合适的头文件。当1-wire将您的USART输出短接到地时,运行调试器的额外功耗可能会导致您遇到的问题? –

+0

感谢您的回复。起初,我设置漏极开路,并通过外部4.7k电阻将其拉高,当我试图读取设备的激光ROM编号并且一切正常时,调试器中的读数与saleae中的读数相同,所以我想知道是否我把它设置为pushpull,并在内部拉起来,它会工作,它确实,所以我只是把它留在那里:)。将其改回漏管并将其从外部拉起来并不能提供帮助。我也有同样的问题。 – Dziat

+0

我发现了另一件可以提供帮助的东西。让我们调用这3个可能的选项来运行该程序FS全速,断点选项BP和SFR查看SFR。我读到:FS - 0x5BE,BP - 0x2DE,SFR - 0x16E。 4个LSB是小数部分,它们总是很好。尾数部分是0x5B >> 1 = 0x2D,0x2D >> 1 = 0x16。所以(一半的措施)快速解决我只是>> 2我的尾数,它在FS工作,但仍然没有工作在BP和SFR。也许这将是一些线索。 – Dziat

回答

0
Write_1Wire(0xCC); 
Write_1Wire(0xBE); 
  • 发送字节UART和没有读。以fifo接收数据。
Read_1Wire() 
  • 读取旧的FIFO此数据。
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; 
} 
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