CC2538DK: I2C communication with CC2538 on SmartRF06 Evaluation Board

Hi Chen,

I am trying to read data from my VCNL 4200, the read format is like

So, I have to send the command: "0x08H_L", how to send commands in I2C.

Please review my code too, I am using VCNL4200 demo board it has configure Pullup in board.

#define EXAMPLE_PIN_I2C_SCL             GPIO_PIN_2

#define EXAMPLE_PIN_I2C_SDA             GPIO_PIN_3

#define EXAMPLE_GPIO_I2C_BASE           GPIO_B_BASE      

#define SLAVE_ADDRESS 0x51      //Slave addr of VCNL4200

int main(void)

{

     uint32_t pui32DataRx;

     uint32_t i,x;

     char output[8];

   SysCtrlClockSet(false, false, SYS_CTRL_SYSDIV_16MHZ);

   //  The I2C peripheral must be enabled before use.

   SysCtrlPeripheralEnable(SYS_CTRL_PERIPH_I2C);

   // Do reset of I2C module

   SysCtrlPeripheralReset(SYS_CTRL_PERIPH_I2C);

   // Configure I2C pins

   GPIOPinTypeI2C(EXAMPLE_GPIO_I2C_BASE, EXAMPLE_PIN_I2C_SCL);

   GPIOPinTypeI2C(EXAMPLE_GPIO_I2C_BASE, EXAMPLE_PIN_I2C_SDA);

   // Configure pins as peripheral input and output

   IOCPinConfigPeriphInput(EXAMPLE_GPIO_I2C_BASE, EXAMPLE_PIN_I2C_SCL,

                           IOC_I2CMSSCL);

   IOCPinConfigPeriphInput(EXAMPLE_GPIO_I2C_BASE, EXAMPLE_PIN_I2C_SDA,

                           IOC_I2CMSSDA);    

   IOCPinConfigPeriphOutput(EXAMPLE_GPIO_I2C_BASE, EXAMPLE_PIN_I2C_SCL,

                            IOC_MUX_OUT_SEL_I2C_CMSSCL);

   IOCPinConfigPeriphOutput(EXAMPLE_GPIO_I2C_BASE, EXAMPLE_PIN_I2C_SDA,

                            IOC_MUX_OUT_SEL_I2C_CMSSDA);  

   HWREG(I2CM_CR) |= I2CM_CR_LPBK;

   I2CMasterInitExpClk(SysCtrlClockGet(), false);

   I2CSlaveEnable(); // TBD is this needed or done by I2CSlaveInit???

   I2CSlaveInit(SLAVE_ADDRESS);

   uint8_t masterSend = 0x08H_L; // error here, type not matching

   while(1){

   I2CMasterSlaveAddrSet(SLAVE_ADDRESS, false);

   I2CMasterDataPut(masterSend);

   I2CMasterControl(I2C_MASTER_CMD_BURST_SEND_START);

       I2CMasterIntClear();

       while(!(I2CSlaveStatus() & I2C_SLAVE_ACT_RREQ))

       {

       }

   I2CMasterSlaveAddrSet(SLAVE_ADDRESS, true);

   I2CMasterControl(I2C_MASTER_CMD_BURST_RECEIVE_START);

   printf("read start\n");

   while(!(I2CSlaveIntStatus(false)))

   {

     ;

   }

   I2CSlaveIntClear();

   while(!(I2CSlaveStatus() & I2C_SLAVE_ACT_TREQ))

   {

     ;

   }

       pui32DataRx = I2CMasterDataGet();

       sprintf(output, "%.1f", pui32DataRx);

       printf("rec = ");

       for(i=0; i<=sizeof(output); i++){

         printf("%c", output[i]);

       }

       printf("\n");

   }

}

According to my understanding to the datasheet, it should be send command 0x08 and you can read two continuous bytes which is PSPDATA_L and PS_DATA_H. 

#define EXAMPLE_PIN_I2C_SCL             GPIO_PIN_2
#define EXAMPLE_PIN_I2C_SDA             GPIO_PIN_3
#define EXAMPLE_GPIO_I2C_BASE           GPIO_B_BASE      

//*****************************************************************************
//
// Number of I2C data packets to send.
//
//*****************************************************************************
//#define NUM_I2C_DATA 3

//*****************************************************************************
//
// Set the address for slave module. This is a 7-bit address sent in the
// following format:
//                      [A6:A5:A4:A3:A2:A1:A0:RS]
//
// A zero in the "RS" position of the first byte means that the master
// transmits (sends) data to the selected slave, and a one in this position
// means that the master receives data from the slave.
//
//*****************************************************************************
#define SLAVE_ADDRESS 0x51      //Slave addr of VCNL4200


//*****************************************************************************
//
// Configure the I2C0 master and slave and connect them using loopback mode.
//
//*****************************************************************************
int
main(void)
{
      uint32_t pui32DataRx = 1;
      uint32_t i,x;
      char output[8];
      uint8_t masterSend;

    //
    // Set the clocking to run directly from the external crystal/oscillator.
    // (no ext 32k osc, no internal osc)
    //
    SysCtrlClockSet(false, false, SYS_CTRL_SYSDIV_16MHZ);

    //
    //  The I2C peripheral must be enabled before use.
    //
    SysCtrlPeripheralEnable(SYS_CTRL_PERIPH_I2C);
    
    //
    // Do reset of I2C module
    //
    SysCtrlPeripheralReset(SYS_CTRL_PERIPH_I2C);

    //
    // Configure I2C pins
    //
    GPIOPinTypeI2C(EXAMPLE_GPIO_I2C_BASE, EXAMPLE_PIN_I2C_SCL);
    GPIOPinTypeI2C(EXAMPLE_GPIO_I2C_BASE, EXAMPLE_PIN_I2C_SDA);

    //
    // Configure pins as peripheral input and output
    //
    IOCPinConfigPeriphInput(EXAMPLE_GPIO_I2C_BASE, EXAMPLE_PIN_I2C_SCL, 
                            IOC_I2CMSSCL);
    IOCPinConfigPeriphInput(EXAMPLE_GPIO_I2C_BASE, EXAMPLE_PIN_I2C_SDA,
                            IOC_I2CMSSDA);    
    IOCPinConfigPeriphOutput(EXAMPLE_GPIO_I2C_BASE, EXAMPLE_PIN_I2C_SCL,
                             IOC_MUX_OUT_SEL_I2C_CMSSCL);
    IOCPinConfigPeriphOutput(EXAMPLE_GPIO_I2C_BASE, EXAMPLE_PIN_I2C_SDA,
                             IOC_MUX_OUT_SEL_I2C_CMSSDA);  
          
        
    //
    // Enable loopback mode.  Loopback mode is a built in feature that is
    // useful for debugging I2C operations.  It internally connects the I2C
    // master and slave terminals, which effectively let's you send data as
    // a master and receive data as a slave.
    // NOTE: For external I2C operation you will need to use external pullups
    // that are stronger than the internal pullups.  Refer to the datasheet for
    // more information.
    //
    HWREG(I2CM_CR) |= I2CM_CR_LPBK;

    //
    // Enable and initialize the I2C master module.  Use the system clock for
    // the I2C module.  The last parameter sets the I2C data transfer rate.
    // If false the data rate is set to 100kbps and if true the data rate will
    // be set to 400kbps.  For this example we will use a data rate of 100kbps.
    //
    I2CMasterInitExpClk(SysCtrlClockGet(), false);

    //
    // Enable the I2C slave module. This module is enabled only for testing
    // purposes.  It does not need to be enabled for proper operation of the
    // I2Cx master module.
    //
    I2CSlaveEnable(); // TBD is this needed or done by I2CSlaveInit???

    //
    // Set the slave address to SLAVE_ADDRESS.  In loopback mode, it's an
    // arbitrary 7-bit number (set in a macro above) that is sent to the
    // I2CMasterSlaveAddrSet function.
    //
    I2CSlaveInit(SLAVE_ADDRESS);
    
    
    / Config /
    masterSend = 0x00;
    
    I2CMasterSlaveAddrSet(SLAVE_ADDRESS, false);
    
    I2CMasterDataPut(masterSend);
    
    I2CMasterControl(I2C_MASTER_CMD_BURST_SEND_START);
       
      //Clear the master inturrupt Source
        I2CMasterIntClear();

        //
        // Wait until the slave has received and acknowledged the data.
        //
        while(!(I2CSlaveStatus() & I2C_SLAVE_ACT_RREQ))
        {
        }
        printf("ALS_CONF\n");
    
    /* Config END*/
        
        
    / Master read / 
    masterSend = 0x08;
    I2CMasterSlaveAddrSet(SLAVE_ADDRESS, false);
    
    I2CMasterControl(I2C_MASTER_CMD_BURST_RECEIVE_START);
        
    I2CMasterDataPut(masterSend);
    
    I2CMasterControl(I2C_MASTER_CMD_BURST_SEND_START);
       
        //
        // Wait until the slave has received and acknowledged the data.
        //
        while(!(I2CSlaveStatus() & I2C_SLAVE_ACT_RREQ))
        {
        }
        printf("ALS_Data \n");
        
    //
    // Modifiy the data direction to true, so that seeing the address will
    // indicate that the I2C Master is initiating a read from the slave.
    //
    I2CMasterSlaveAddrSet(SLAVE_ADDRESS, true);
    
    //
    // Do a dummy receive to make sure you don't get junk on the first receive.
    //
    I2CMasterControl(I2C_MASTER_CMD_BURST_RECEIVE_START);
   

    //
    // Dummy acknowledge and wait for the receive request from the master.
    // This is done to clear any flags that should not be set.
    //

    while(!(I2CSlaveStatus() & I2C_SLAVE_ACT_TREQ))
    {
      ;
    }
    
    printf("read start\n");
        //
        // Read the data from the master.
        //
    
        pui32DataRx = I2CMasterDataGet();
//    
//        sprintf(output, "%.1f", pui32DataRx);
//        
//        printf("rec = ");
//        for(i=0; i<=sizeof(output); i++){
//          
//          printf("%c", output[i]);
//        }
        
        printf("rec = %d\n", pui32DataRx);
        printf("\n");
      
    
}

Thanks for check of Datasheet.

My slave is not giving this action I2C_SLAVE_ACT_TREQ,

I mean below loop is not completing, after sent read request to Slave.

while(!(I2CSlaveStatus() & I2C_SLAVE_ACT_TREQ))

   {

     ;

   }

Thank you.

There are accelerometer and lightsensor example in cc2538 foundation firmware.

uint16_t ui16Dummy;

    //
    // Set the clocking to run directly from the external crystal/oscillator.
    // (no ext 32k osc, no internal osc)
    //
    SysCtrlClockSet(false, false, SYS_CTRL_SYSDIV_32MHZ);

    //
    // Set IO clock to the same as system clock
    //
    SysCtrlIOClockSet(SYS_CTRL_SYSDIV_32MHZ);
     
    //
    // Enable RF Core (needed to enable temp sensor)
    //
    SysCtrlPeripheralEnable(SYS_CTRL_PERIPH_RFC);
        
    //
    // Connect sensor to ADC
    //
    HWREG(CCTEST_TR0) |= CCTEST_TR0_ADCTM_M;

    
    //
    // Configure ADC, Internal reference, 512 decimation rate (12bit)
    //
    SOCADCSingleConfigure(SOCADC_12_BIT, SOCADC_REF_INTERNAL);
     
    //
    // Loop forever.
    //
    while(1)
    {
        //
        // Trigger single conversion on internal temp sensor
        //
        SOCADCSingleStart(SOCADC_AIN6);
        
        //
        // Wait until conversion is completed
        //
        while(!SOCADCEndOfCOnversionGet())
        {
        }

        //
        // Get data and shift down based on decimation rate
        //
        ui16Dummy = SOCADCDataGet() >> SOCADC_12_BIT_RSHIFT;
        
        printf("d = %s\n",ui16Dummy ); 
for(int i=0;i<1000000;i++) { } 
}

I was getting always 2047, as d, even varying light its not varying

Hi,

I am getting Analog out of ALS, I am trying to convert this as abovebut always getting same value can you please check