RTOS/LAUNCHXL-CC1310: Read data from sensor BMP280 via I2C

Do you call “I2C_init();” before you use I2C?

I mean to do pull-high on your phisical I2C pins as it is in the following CC1350STK schematic.

Thank for your reply.

i change my code like below.

txBuffer[0]= 0x0001;
i2cTransaction.writeBuf = txBuffer;
i2cTransaction.writeCount = 1;
i2cTransaction.readBuf = rxBuffer;
i2cTransaction.readCount = 1;
i2cTransaction.slaveAddress = Board_BMP_ADDR;

but it still doesn't work.

Best Regards,

youyun

Thank for you reply.

I went back to read BMP280 datasheet again. Here are the method to read the data.

So, I change my code like below. I think my BMP280 slaveaddress is correct.

And the register address is change like the picture show.

But I still can't make the function I2C_transfer() return true.

void *mainThread(void *arg0)

{

//I2C
I2C_Handle i2c;
I2C_Params i2cParams;
I2C_Transaction i2cTransaction;
//BMP280
uint8_t txBuffer[1];
uint8_t rxBuffer[2];

/* Call driver init functions */
GPIO_init();
I2C_init();

/* Configure the LED pin */
GPIO_setConfig(Board_GPIO_LED0, GPIO_CFG_OUT_STD | GPIO_CFG_OUT_LOW);

/* Create I2C for usage */
I2C_Params_init(&i2cParams);
i2cParams.bitRate = I2C_400kHz;
//i2cParams.transferMode =I2C_MODE_CALLBACK; //I2C_MODE_CALLBACK I2C_MODE_BLOCKING
//i2cParams.transferCallbackFxn = NULL;
i2c = I2C_open(0, &i2cParams); 
if (i2c == NULL) {
puts("Error Initializing I2C");
while (1);
}
else{
puts("i2c open");
}

while(1){

//I2C read (BMP280)

txBuffer[0]= BMP280_REG_PRESSURE; //BMP280_REG_PRESSURE value is 0xF6
i2cTransaction.slaveAddress = BMP280_ADDR; //BMP280_ADDR value is 0x77
i2cTransaction.writeBuf = txBuffer;
i2cTransaction.writeCount = 1;
i2cTransaction.readBuf = rxBuffer;
i2cTransaction.readCount = 2;

if (I2C_transfer(i2c, &i2cTransaction)){
puts("I2C Function work");
}
else{
puts("I2C Function Failed.");
}

}

Any help will be greatly appreciated!

Best Regards,

youyun

Thank for you reply.

After using scope, I found out that slaveaddress isn't work in 0x77.

I change the slaveaddress to 0x76 and i2c_transfer() is work.

But the waveform aren't the same as when I connect the sensor to Arduino.

The picture below is bmp280 connect to arduino and CC1310.

The two picture waveform aren't the same.

The SCL part is pretty different between two of them.

How should I do?

Anything suggest?

BMP280 connet to Arduino.

BMP280 connect to CC1310.

Best Regards,

youyun

Thank for you reply.

Yes, I try to add pull-high between LAUNCHXL-CC1310 DIO_4/DIO_5 and BMP280.

But the result is the same like the waveform show in the picture. Any suggestion?

And now I have another problem. 

Read BMP280 memory map I found out that I only catch the reset state.

What should I do?

Best Regards,

youyun

Below picture is BMP280 Timing Diagram.

Below is BMP280 memory map.

Below is my code.

void *mainThread(void *arg0)
{
    unsigned int    i;
    //I2C
    I2C_Handle      i2c;
    I2C_Params      i2cParams;
    I2C_Transaction i2cTransaction;
    //BMP280
    uint8_t    txBuffer[1];
    uint8_t    rxBuffer[2];
    float bmpValue;
    char bmpData[32];
    bool test;

    /* Call driver init functions */
    GPIO_init();
    I2C_init();

    /* Configure the LED pin */
    GPIO_setConfig(Board_GPIO_LED0, GPIO_CFG_OUT_STD | GPIO_CFG_OUT_LOW);

    /* Create I2C for usage */
    I2C_Params_init(&i2cParams);
    i2cParams.bitRate = I2C_400kHz;
    //i2cParams.transferMode =I2C_MODE_CALLBACK; //I2C_MODE_CALLBACK I2C_MODE_BLOCKING
    //i2cParams.transferCallbackFxn = NULL;
    i2c = I2C_open(0, &i2cParams);      //(0,&i2cParams)
    if (i2c == NULL) {
        puts("Error Initializing I2C");
        while (1);
    }
    else{
        puts("i2c open");
    }

    while(1){
        //I2C read
        //BMP280
        //txBuffer[0]=BMP280_REG_ID;
        txBuffer[0]= BMP280_REG_PRESSURE;       //BMP280_REG_PRESSURE value is 0xF6
        i2cTransaction.slaveAddress = BMP280_ADDR;  //BMP280_ADDR value is 0x76
        i2cTransaction.writeBuf = txBuffer;
        i2cTransaction.writeCount = 1;
        i2cTransaction.readBuf = rxBuffer;
        i2cTransaction.readCount = 2;


        for(i=0;i<100;i++){
        if (I2C_transfer(i2c, &i2cTransaction)){
            //bmpValue = sensorBmp280Convert(rxBuffer);
            puts("I2C Function work");

            sprintf(bmpData,"%d",rxBuffer[0]);  //0xF6 data
            puts(bmpData);
            sprintf(bmpData,"%d",rxBuffer[1]);  //0xF7 data
            puts(bmpData);
            sprintf(bmpData,"%d",rxBuffer[2]);  //0xF8 data
            puts(bmpData);
        }
        else{
            puts("I2C Function Failed.");
        }
        }

    }

Below is the result.

Thank for you reply.

Yes, I have the BMP280 on a PCB.

Best Regards,

youyun

Thank for you reply.

I read the Bmp280 datasheet again and found out that getting the sensor data needs to i2c write function first.

I added the code like below picture and I caught the data from sensor succeed.

But i2c timing diagram still a lot of different between the CC1310 and arduino.

After I read the bmp280 calculate way which TER post the link, I still don't know how to do.

Any suggestion?

Best Regards,

youyun

Here is my code.

//BMP280
#define BMP280_ADDR 0x76    //0x76 & 0x77 
#define BMP280_REG_PRESSURE 0xF7
#define BMP280_REG_CTRL 0xF4
#define BMP280_REG_TEMPATURE    0xFA
#define BMP280_WorkMode 0x27    //0x27 temp[2:0]=001 press[2:0]=001 mode[1:0]=11(normal mode)
#define BMP280_REG_ID 0xD0
#define BMP280_CHIPID 0x58

void *mainThread(void *arg0)
{
    //I2C
    I2C_Handle      i2c;
    I2C_Params      i2cParams;
    I2C_Transaction i2cTransaction;
    //BMP280
    uint8_t    txBuffer[2];
    uint8_t    rxBuffer[6];
    char bmpData[32];

    I2C_init();

    /* Create I2C for usage */
    I2C_Params_init(&i2cParams);
    i2cParams.bitRate = I2C_400kHz;
    //i2cParams.transferMode =I2C_MODE_CALLBACK; //I2C_MODE_CALLBACK I2C_MODE_BLOCKING
    //i2cParams.transferCallbackFxn = NULL;
    i2c = I2C_open(0, &i2cParams);      //(0,&i2cParams)
    if (i2c == NULL) {
        puts("Error Initializing I2C");
        while (1);
    }
    else{
        puts("i2c open");
    }

    while(1){
        //I2C write
        //BMP280 power mode change
        //control register 0xF4
        txBuffer[0]= BMP280_REG_CTRL;
        txBuffer[1]= BMP280_WorkMode;
        i2cTransaction.slaveAddress = BMP280_ADDR;
        i2cTransaction.writeBuf = txBuffer;
        i2cTransaction.writeCount = 2;
        i2cTransaction.readBuf = rxBuffer;
        i2cTransaction.readCount = 0;

        if (I2C_transfer(i2c, &i2cTransaction)){
            puts("I2C BMP280 power mode");
        }

        //I2C read
        //BMP280 memory map pressure to temperature
        txBuffer[0]= BMP280_REG_PRESSURE;       //BMP280_REG_PRESSURE value is 0xF6
        i2cTransaction.slaveAddress = BMP280_ADDR;  //BMP280_ADDR value is 0x76
        i2cTransaction.writeBuf = txBuffer;
        i2cTransaction.writeCount = 1;
        i2cTransaction.readBuf = rxBuffer;
        i2cTransaction.readCount = 6;

        for(i=0;i<1000;i++){
        if (I2C_transfer(i2c, &i2cTransaction)){
            //bmpValue = sensorBmp280Convert(rxBuffer);
            puts("I2C Function work");

            sprintf(bmpData,"%d",rxBuffer[0]);  //0xF7 data press_msb
            puts(bmpData);
            sprintf(bmpData,"%d",rxBuffer[1]);  //0xF8 data press_lsb
            puts(bmpData);
            sprintf(bmpData,"%d",rxBuffer[2]);  //0xF9 data press_xlsb oversampling
            puts(bmpData);
            sprintf(bmpData,"%d",rxBuffer[3]);  //0xFA data temperature_msb
            puts(bmpData);
            sprintf(bmpData,"%d",rxBuffer[4]);  //0xFB data temperature_lsb
            puts(bmpData);
            sprintf(bmpData,"%d",rxBuffer[5]);  //0xFC data temperature_xlsb oversampling
            puts(bmpData);

        }
        else{
            puts("I2C Function Failed.");
        }
        }

    }

The data I caught from bmp280.

The bmp280 timing diagram on cc1310.

The timing diagram of arduino and cc1310.

As far as I can see you are not addressing my question:

"This board is from adafruit with a regulator, some 5 V <-> 3.3 V conversion. From what I see from the schematic for this board the pin row row is on the 5 V domain. Have you review the schematic and checked how the extra components on the board impact the communication?"

Before starting to look into the software you have to fully understand the hardware.