c语言 - 尝试在RPI上使用I2C和BCM2835读取光传感器 - TSL2561

Question

我哥哥和我已经试着让这个工作几天了，我们只是不知道我们做错了什么，我们真的可以使用一些帮助，请!

我们试图完成的是通过我们自己用C语言编写的程序，使用BCM2835库从RPI扩展板上的光传感器读取数据。

这是我们使用的光传感器:TSL2561https://cdn-shop.adafruit.com/datasheets/TSL2561.pdf

我们使用的是安装了raspberry pi B+的型号(通过noobs)。

这是我们正在使用的C库:http://www.airspayce.com/mikem/bcm2835/

我通过raspian配置激活I2c。

，我通过i2ctools检测到光传感器，它正确显示为地址0x29。

我们读取得到0值，我们用示波器测试了我们的命令，看起来他确实ACK了写命令。他什么都不回…

有人能帮帮我们吗?

#include <bcm2835.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
uint16_t clk_div = BCM2835_I2C_CLOCK_DIVIDER_148;
uint8_t slave_address = 0x29; //0101001 - this is the sensor address
uint64_t delay = 70000;

int main(int argc, char **argv)
{
    /*
    DATA0LOW    Ch  7:0 ADC channel 0 lower byte    
    DATA0HIGH   Dh  7:0 ADC channel 0 upper byte
    */

    char buffer[10]={0};
    char addr;
    uint16_t data;
    uint8_t data2;
    int i =0;
    char writeBuff[1] = {0x8C}; ////Address the Ch0 lower data register
    char readBuff[10];
    char writeBuff2[2] = {0x8D}; ////Address the Ch0 upper data register
    char readBuff2[10];

    char *wb_ptr,*r_ptr,*wb_ptr2,*r_ptr2;
    wb_ptr = writeBuff;
    wb_ptr2 = writeBuff2;
    r_ptr = readBuff;
    r_ptr2 = readBuff2;
    printf("Running ... n");
    bcm2835_init():
    bcm2835_i2c_begin();
    bcm2835_i2c_setSlaveAddress(slave_address); //0x29
    printf("Clock divider set to: %dn", clk_div);
    printf("Slave address set to: %d or %Xn",slave_address,slave_address);
    //needed according to datasheet to read although unsure if it needs to be sent in two writes or in one ? 0x83 instead of 0x80 + 0x03 ?
    bcm2835_i2c_write(0x80, 1); //command register
    bcm2835_i2c_write(0x03, 1); //command itself
    bcm2835_delayMicroseconds(delay);
    //--------------------------

    while (1)
    {
    printf("reading data from light sensorn");
    bcm2835_i2c_write(wb_ptr, 1); // 0x8C
    bcm2835_delayMicroseconds(delay);
    data = bcm2835_i2c_read(readBuff,1);
    bcm2835_delayMicroseconds(delay);
    printf("Read Result 1 = %dn", data);
    bcm2835_i2c_write(wb_ptr2, 1); //0x8D
    bcm2835_delayMicroseconds(delay);
    data2 = bcm2835_i2c_read(readBuff2,1);
    bcm2835_delayMicroseconds(delay);
    printf("Read Result 2 = %dn", data);
    bcm2835_delay(1000);
    }
    bcm2835_i2c_end();
    bcm2835_close();
    printf("... donen");
    return 0;
}

快速编辑

#include <bcm2835.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
uint16_t clk_div = BCM2835_I2C_CLOCK_DIVIDER_148;
uint8_t slave_address = 0x29; //0101001 - this is the sensor address
uint64_t delay = 70000;

int main(int argc, char **argv)
{
    /*
    DATA0LOW    Ch  7:0 ADC channel 0 lower byte    
    DATA0HIGH   Dh  7:0 ADC channel 0 upper byte
    */
    /*
    enum    bcm2835I2CReasonCodes { BCM2835_I2C_REASON_OK = 0x00, BCM2835_I2C_REASON_ERROR_NACK = 0x01, BCM2835_I2C_REASON_ERROR_CLKT = 0x02, BCM2835_I2C_REASON_ERROR_DATA = 0x04 }
    */

    char buffer[10]={0};
    char addr;
    uint16_t data;
    uint8_t data2;
    uint8_t error = 0xff;
    int i =0;
    char writeBuff[1] = {0x8C}; ////Address the Ch0 lower data register
    char readBuff[10];
    char writeBuff2[2] = {0x8D}; ////Address the Ch0 upper data register
    char readBuff2[10];
    char writeBuff3[2] = {0x80}; 
    char writeBuff4[2] = {0x03}; 

    char *wb_ptr,*r_ptr,*wb_ptr2,*r_ptr2,*r_ptr3,*r_ptr4;
    wb_ptr = writeBuff;
    wb_ptr2 = writeBuff2;
    r_ptr = readBuff;
    r_ptr2 = readBuff2;
    r_ptr3 = writeBuff3;
    r_ptr4 = writeBuff4;
    printf("Running ... n");
    bcm2835_init();
    bcm2835_i2c_begin();
    bcm2835_i2c_setSlaveAddress(slave_address); //0x29
    printf("Clock divider set to: %dn", clk_div);
    printf("Slave address set to: %d or %Xn",slave_address,slave_address);
    //needed according to datasheet to read although unsure if it needs to be sent in two writes or in one ? 0x83 instead of 0x80 + 0x03 ?
    bcm2835_i2c_write(r_ptr3, sizeof(r_ptr3)); //command register
    bcm2835_i2c_write(r_ptr4, sizeof(r_ptr4)); //command itself
    bcm2835_delayMicroseconds(delay);
    //--------------------------

    // Blink
    while (1)
    {
    printf("reading data from light sensorn");
    error = bcm2835_i2c_write(wb_ptr, sizeof(wb_ptr)); // 0x8C
    bcm2835_delayMicroseconds(delay);
    data = bcm2835_i2c_read(readBuff,sizeof(readBuff));
    bcm2835_delayMicroseconds(delay);
    printf("readbuff1 = 0x%02X n",readBuff);
    printf("error result = 0x%02Xn", error);
    printf("Read Result 1 = 0x%02Xn", data);
    error = bcm2835_i2c_write(wb_ptr2, sizeof(wb_ptr2)); //0x8D
    bcm2835_delayMicroseconds(delay);
    data2 = bcm2835_i2c_read(readBuff2,sizeof(readBuff2));
    bcm2835_delayMicroseconds(delay);
    printf("readbuff2 = 0x%02X n",readBuff2);
    printf("error result = 0x%02Xn", error);
    printf("Read Result 2 = 0x%02Xn", data2);
    bcm2835_delay(1000);
    }
    bcm2835_i2c_end();
    bcm2835_close();
    printf("... donen");
    return 0;
}

Answer 1

我设法修复了它，我有几个问题，其中一个是我正在处理错误的地址发送命令，它必须是0xa0而不是0x80。

#include <bcm2835.h>
#include <stdio.h>

int main(void)
{
    /*
    DATA0LOW    Ch  7:0 ADC channel 0 lower byte    
    DATA0HIGH   Dh  7:0 ADC channel 0 upper byte
    */
    /*
    enum    bcm2835I2CReasonCodes { BCM2835_I2C_REASON_OK = 0x00, BCM2835_I2C_REASON_ERROR_NACK = 0x01, BCM2835_I2C_REASON_ERROR_CLKT = 0x02, BCM2835_I2C_REASON_ERROR_DATA = 0x04 }
    */
      if (!bcm2835_init())
    return 1;
    char uitgelezenTempWaarde[1];           
    int totalTemp[2];
    int error =0;

    bcm2835_i2c_begin();                    // start i2c
    bcm2835_i2c_setSlaveAddress(0x29);      // slave address
    bcm2835_i2c_set_baudrate(1000);         // default
    //----------- turn channels on for measurement ------
    uitgelezenTempWaarde[0] = 0xa0;             
    error = bcm2835_i2c_write(uitgelezenTempWaarde,1);
    if(error != 0x00)
    {
        printf("i2c error! : 0x%02X n",error);
    }
    uitgelezenTempWaarde[0] = 0x03;             
    error = bcm2835_i2c_write(uitgelezenTempWaarde,1);
    if(error != 0x00)
    {
        printf("i2c error! : 0x%02X n",error);
    }
    bcm2835_delay(500);
    error = bcm2835_i2c_read(uitgelezenTempWaarde,1);
    if(error != 0x00)
    {
        printf("i2c error! : 0x%02X n",error);
    }
    //----------- read data ------
        uitgelezenTempWaarde[0] = 0xac;             //DATA0LOW  Ch  7:0 ADC channel 0 lower byte
    error = bcm2835_i2c_write(uitgelezenTempWaarde,1);      
    if(error != 0x00)
    {
        printf("i2c error! : 0x%02X n",error);
    }
    error = bcm2835_i2c_read(uitgelezenTempWaarde,1);
    if(error != 0x00)
    {
        printf("i2c error! : 0x%02X n",error);
    }
        totalTemp[1]= (int)uitgelezenTempWaarde[0];
        uitgelezenTempWaarde[0] = 0xad;             //DATA0HIGH Dh  7:0 ADC channel 0 upper byte
    error = bcm2835_i2c_write(uitgelezenTempWaarde,1);
    if(error != 0x00)
    {
        printf("i2c error! : 0x%02X n",error);
    }
    error = bcm2835_i2c_read(uitgelezenTempWaarde,1);
    if(error != 0x00)
    {
        printf("i2c error! : 0x%02X n",error);
    }   
        totalTemp[0] = (int)uitgelezenTempWaarde[0]; //
        totalTemp[0] *= 256; //hex conversion for the highest byte so it is seen as a high number (16 bits)
        printf("The light value is :%dn",totalTemp[0]+totalTemp[1]);

    bcm2835_i2c_end();
    bcm2835_close();
    return 0;
}