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我正在尝试通过 I2C 协议控制 BMP180。问题是 Pic 一直在重置。我改变了图片，它是一样的。

配置代码如下：

#include <xc.h>

// #pragma config statements should precede project file includes.
// Use project enums instead of #define for ON and OFF.

// CONFIG1H
#pragma config OSC = INTIO7     // Oscillator Selection bits (Internal     oscillator block, CLKO function on RA6, port function on RA7)
#pragma config FCMEN = OFF      // Fail-Safe Clock Monitor Enable bit (Fail-Safe Clock Monitor disabled)
#pragma config IESO = OFF       // Internal/External Oscillator Switchover bit (Oscillator Switchover mode disabled)

// CONFIG2L
#pragma config PWRT = OFF       // Power-up Timer Enable bit (PWRT disabled)
#pragma config BOREN = SBORDIS  // Brown-out Reset Enable bits (Brown-out  Reset enabled in hardware only (SBOREN is disabled))
#pragma config BORV = 3         // Brown Out Reset Voltage bits (Minimum setting)

// CONFIG2H
#pragma config WDT = OFF         // Watchdog Timer Enable bit (WDT disabled)
#pragma config WDTPS = 32768    // Watchdog Timer Postscale Select bits (1:32768)

// CONFIG3H
#pragma config CCP2MX = PORTC   // CCP2 MUX bit (CCP2 input/output is multiplexed with RC1)
#pragma config PBADEN = ON      // PORTB A/D Enable bit (PORTB<4:0> pins are configured as analog input channels on Reset)
#pragma config LPT1OSC = OFF    // Low-Power Timer1 Oscillator Enable bit (Timer1 configured for higher power operation)
#pragma config MCLRE = ON       // MCLR Pin Enable bit (MCLR pin enabled; RE3 input pin disabled)

// CONFIG4L
#pragma config STVREN = ON      // Stack Full/Underflow Reset Enable bit (Stack full/underflow will cause Reset)
#pragma config LVP = ON         // Single-Supply ICSP Enable bit (Single-Supply ICSP enabled)
#pragma config XINST = OFF      // Extended Instruction Set Enable bit (Instruction set extension and Indexed Addressing mode disabled (Legacy mode))

// CONFIG5L
#pragma config CP0 = OFF        // Code Protection bit (Block 0 (000800-001FFFh) not code-protected)
#pragma config CP1 = OFF        // Code Protection bit (Block 1 (002000-003FFFh) not code-protected)
#pragma config CP2 = OFF        // Code Protection bit (Block 2 (004000-005FFFh) not code-protected)
#pragma config CP3 = OFF        // Code Protection bit (Block 3 (006000-007FFFh) not code-protected)

// CONFIG5H
#pragma config CPB = OFF        // Boot Block Code Protection bit (Boot block (000000-0007FFh) not code-protected)
#pragma config CPD = OFF        // Data EEPROM Code Protection bit (Data EEPROM not code-protected)

// CONFIG6L
#pragma config WRT0 = OFF       // Write Protection bit (Block 0 (000800-001FFFh) not write-protected)
#pragma config WRT1 = OFF       // Write Protection bit (Block 1 (002000-003FFFh) not write-protected)
#pragma config WRT2 = OFF       // Write Protection bit (Block 2 (004000-005FFFh) not write-protected)
#pragma config WRT3 = OFF       // Write Protection bit (Block 3 (006000-007FFFh) not write-protected)

// CONFIG6H
#pragma config WRTC = OFF       // Configuration Register Write Protection bit (Configuration registers (300000-3000FFh) not write-protected)
#pragma config WRTB = OFF       // Boot Block Write Protection bit (Boot block (000000-0007FFh) not write-protected)
#pragma config WRTD = OFF       // Data EEPROM Write Protection bit (Data EEPROM not write-protected)

// CONFIG7L
#pragma config EBTR0 = OFF      // Table Read Protection bit (Block 0 (000800-001FFFh) not protected from table reads executed in other blocks)
#pragma config EBTR1 = OFF      // Table Read Protection bit (Block 1 (002000-003FFFh) not protected from table reads executed in other blocks)
#pragma config EBTR2 = OFF      // Table Read Protection bit (Block 2 (004000-005FFFh) not protected from table reads executed in other blocks)
#pragma config EBTR3 = OFF      // Table Read Protection bit (Block 3 (006000-007FFFh) not protected from table reads executed in other blocks)

// CONFIG7H
#pragma config EBTRB = OFF      // Boot Block Table Read Protection bit (Boot block (000000-0007FFh) not protected from table reads executed in other blocks)

和主要代码：

#include <xc.h>
#include <stdint.h>

#define EAUSART_V4  

#include <plib/usart.h> 
#include "i2c.h"

#define OSCCON_Init         0b11111111   

#define BMP180_W 0xEE
#define BMP180_R 0xEF
#define I2C_master_ACK 1
#define I2C_master_NOACK 0
#define I2C_WRITE_CMD 0
#define I2C_READ_CMD 1
#define I2C_START_CMD 0
#define I2C_REP_START_CMD 1
#define I2C_REQ_ACK 0
#define I2C_REQ_NOACK 0

#define SDA_TRIS  TRISCbits.RC4
#define SCL_TRIS  TRISCbits.RC3


char CaracterRx;
int nummer = 0;


uint8_t data;
uint16_t temperature;

uint8_t BMP180_present(void);
void i2c_master_ack(unsigned char);
uint16_t BMP180_Temperature_Lecture(void);

void main(void) {

char hello[] ={"hello there\r\n\0"};

 SSPSTATbits.CKE = 1;

SDA_TRIS = 1;
SCL_TRIS = 1;

OSCCON = OSCCON_Init;

OpenUSART(USART_TX_INT_ON &
        USART_RX_INT_ON &       
        USART_ASYNCH_MODE &     
        USART_EIGHT_BIT &       
        USART_CONT_RX &         
        USART_BRGH_HIGH, 51);  



 putsUSART("2"); 
 for(int i=0; i<10 ; i++)
__delay_ms(50);

SSPADD=19; 
OpenI2C(MASTER,SLEW_OFF);


putsUSART(&hello); 
for(int i=0; i<10 ; i++)
  __delay_ms(50);

while(1)
{
data = BMP180_present();

temperature = BMP180_Temperature_Lecture();
nummer = data;
putsUSART(nummer);

for(int i=0; i<50; i++)
   __delay_ms(50);

}
}



uint8_t BMP180_present(void)
{//returns true if a bmp is detected.
//Detection achieved by looking at the device ID, which is fixed at 0x55. 
uint8_t Id;
StartI2C();
WriteI2C(BMP180_W);
WriteI2C(0xD0);
RestartI2C();
WriteI2C(BMP180_R);
Id=ReadI2C();
StopI2C();

return Id;
}

uint16_t BMP180_Temperature_Lecture(void)
{
uint16_t value;
uint8_t prueba1, prueba2;
StartI2C();
WriteI2C(BMP180_W);
WriteI2C(0xF4);
WriteI2C(0x2E);
StopI2C();
__delay_ms(5);

WriteI2C(BMP180_W);
WriteI2C(0xF6);
RestartI2C();
WriteI2C(BMP180_R);
prueba1=ReadI2C();//Value in F6
i2c_master_ack(I2C_master_ACK);
prueba2=ReadI2C();//Value in F7
i2c_master_ack(I2C_master_NOACK);
StopI2C();

value = prueba1<<8 | prueba2;

return value;

}

void i2c_master_ack(unsigned char ack_type)
{
SSPCON2bits.ACKDT = ack_type; // 1 = Not Acknowledge, 0 = Acknowledge
SSPCON2bits.ACKEN = 1; // Enable Acknowledge
while (SSPCON2bits.ACKEN == 1);
}

我通过串行将数据发送到 Arduino，然后将其打印在计算机上。几乎总是当我尝试打印它时，它只打印“2”，有时，他会写句子并打印来自包含 BMP180 的模块的数据。但大多数时候，Arduino 显示给我的是：22222222...我已经测试过设置 MCLR = OFF，但它仍然是一样的。

通道 SDA 和 SCL 的电阻为 4.7k 至 3.5V。该模块采用 3.5V 供电，但图片采用 5V 供电。我不认为这个模块的问题是强度太高。我可能忘记了什么吗？

奇怪的是，当我触摸图片时（当我尝试更换一些电线或其他东西时）它会自动重置。

非常感谢。

曼努埃尔。

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1 回答 1

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听起来你那里有一些严重的噪音问题。乍一看，您的代码似乎没有任何问题。当一个未使用的引脚悬空时，它就像一个高阻抗天线，基本上可以接收附近的任何和所有信号，无论它们是什么。在这种情况下，功耗也会急剧上升。这可以解释为什么每次触摸 PIC 都会重置。根据个人经验，我建议您执行以下部分或全部操作：

  1. 将所有未使用的引脚设置为数字输出，并使用 LAT 寄存器将它们下拉到 gnd。例如，如果您不使用 RA2 引脚，请将其放在 main 函数的开头：

    TRISAbits.RA2 = 0；

    LATAbits.LATA2 = 0；

对所有未使用的引脚执行此操作。它将大大降低您的功耗。

  1. 确保您在 5V（在您的情况下）和复位引脚之间连接了正确的电阻值。如果该值高于或低于数据表中的建议值，有时会出现问题。
  2. 测量相应引脚上的 PIC 电源电压。您可以使用万用表进行此操作，但如果您可以使用示波器，我建议您使用示波器。将其连接到 PIC 的电源引脚并在通过 I2C 发送数据时测量值。电源电压可能会下降，这会导致掉电复位，即在您的情况下电压下降到 3V 以下并且控制器会复位。如果是这种情况，清除 BOREN 位将是一个可能的解决方案，但是，这种功率下降表明您的电路存在更大的问题，因此我建议您进一步研究一下。
于 2015-10-12T21:53:56.693 回答