• State Resolved
  • Locked Locked
  • Replies 7 replies
  • Subscribers 30 subscribers
  • Views 2482 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Tiva I2C Slave Address Problem

sanchezbjc_fi-iee
Intellectual 560 points
Other Parts Discussed in Thread: TM4C123GH6PM

Hello, my name is Juan Carlos

I'm working with a Tiva Launchpad (TM4C123GH6PM), and I try communicate this board with a L3GD20 sensor.

My problem is the transfer the slave address, because I can see the signal of SDA and SCL in the oscilloscope, and I see that this is wrong. Send the image of the signal transfer and write my code.

The slave addres in the signal is 0x54h while the slave addres in code is 0xD4h. I think that the bit MSB in the slave address is lost, i don't know why.

Thanks for your answers.


void L3gd20_Init(void)
{
    I2CMasterSlaveAddrSet(I2C0_BASE,0xD4,false);

    I2CMasterControl(I2C0_BASE, I2C_MASTER_CMD_BURST_SEND_START);
    while(I2CMasterBusy(I2C0_BASE));
    SysCtlDelay(10);
    I2CMasterDataPut(I2C0_BASE, 0xD4);
    I2CMasterControl(I2C0_BASE, I2C_MASTER_CMD_BURST_SEND_CONT);
    while(I2CMasterBusy(I2C0_BASE));
    SysCtlDelay(10);

    I2CMasterDataPut(I2C0_BASE, 0x20);
    I2CMasterControl(I2C0_BASE, I2C_MASTER_CMD_BURST_SEND_CONT);
    while(I2CMasterBusy(I2C0_BASE));
    SysCtlDelay(10);
    I2CMasterDataPut(I2C0_BASE, 0x0F);
    I2CMasterControl(I2C0_BASE, I2C_MASTER_CMD_BURST_SEND_FINISH);
    while(I2CMasterBusy(I2C0_BASE));
}

uint8_t ByteReadL3GD20(uint32_t address)
{
    uint8_t addr,dato;
    addr=address;

    I2CMasterSlaveAddrSet(I2C0_BASE, 0xD4 ,false);

    I2CMasterDataPut(I2C0_BASE, addr);

    I2CMasterControl(I2C0_BASE, I2C_MASTER_CMD_BURST_SEND_START);
    while(I2CMasterBusy(I2C0_BASE));
    SysCtlDelay(100);

   I2CMasterSlaveAddrSet(I2C0_BASE, 0xD5, true);
   I2CMasterControl(I2C0_BASE, I2C_MASTER_CMD_SINGLE_RECEIVE);

   while(I2CMasterBusy(I2C0_BASE));

   I2CMasterControl(I2C0_BASE, I2C_MASTER_CMD_BURST_RECEIVE_FINISH);
   while(I2CMasterBusy(I2C0_BASE));

  dato=I2CMasterDataGet(I2C0_BASE);
   return I2CMasterDataGet(I2C0_BASE);
}


int main(void)
{
   uint8_t gX[2]={0,0};
   uint8_t gY[2]={0,0};
   uint8_t gZ[2]={0,0};

   SysCtlClockSet(SYSCTL_SYSDIV_20| SYSCTL_USE_PLL | SYSCTL_OSC_MAIN | SYSCTL_XTAL_16MHZ);

  //HABILITACIÓN DE PERIFERICOS================================

   SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
   SysCtlPeripheralEnable(SYSCTL_PERIPH_UART3);
   SysCtlPeripheralEnable(SYSCTL_PERIPH_I2C0);
   SysCtlPeripheralReset(SYSCTL_PERIPH_I2C0);

   SysCtlPeripheralEnable(SYSCTL_PERIPH_ADC0);

   SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
   SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);
   SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOC);

//CONFIGURACION DE UARTS=====================================

   GPIOPinConfigure(GPIO_PA0_U0RX); //Debug
   GPIOPinConfigure(GPIO_PA1_U0TX);
   GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);

   GPIOPinConfigure(GPIO_PC6_U3RX); //CPU
   GPIOPinConfigure(GPIO_PC7_U3TX);
   GPIOPinTypeUART(GPIO_PORTC_BASE, GPIO_PIN_6 | GPIO_PIN_7);

   UARTConfigSetExpClk(UART0_BASE, SysCtlClockGet(), 115200,
  (UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE | UART_CONFIG_PAR_NONE));

  UARTConfigSetExpClk(UART3_BASE, SysCtlClockGet(), 115200,
  (UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE | UART_CONFIG_PAR_NONE));

//CONFIGURACION DE I2C=====================================

   GPIOPinConfigure(GPIO_PB2_I2C0SCL);
   GPIOPinConfigure(GPIO_PB3_I2C0SDA);

   GPIOPinTypeI2C(GPIO_PORTB_BASE, GPIO_PIN_3); //SDA
   GPIOPinTypeI2CSCL(GPIO_PORTB_BASE, GPIO_PIN_2); //SCL
   I2CMasterInitExpClk(I2C0_BASE, SysCtlClockGet(), false);

   HWREG(I2C0_BASE + I2C_O_FIFOCTL) = 80008000;

   I2CMasterEnable(I2C0_BASE);


//CONFIGURACION DE TERMINALES DE SALIDA=======================

//CONFIGURACION DE TERMINALES DE ENTRADA=======================

// CONFIGURACION DE CANALES DE CONVRESION ANALOGICA DIGITAL======

// CONFIGURACION SPI==============================================
//========================================================
//CONFIGURACIONES DE INTERRUPCIONES

//INTERRUPCION DE GPIO's

//INTERRUPCION DE COMUNICACIONES

//========================================================
    L3gd20_Init();
   UARTSend(UART0_BASE,(const unsigned char *)&"Programa I2C",18);
   UARTSend(UART0_BASE,(const unsigned char *)&"\n\r",3);
   UARTSend(UART3_BASE,(const unsigned char *)&"Programa I2C",18);
   UARTSend(UART3_BASE,(const unsigned char *)&"\n\r",3);

   while(1)
   {
       gX[0]=ByteReadL3GD20(0x28);
       SysCtlDelay(100);
   }

}

Signal of the : " L3gd20_Init();"

Signal of the " gX[0]=ByteReadL3GD20(0x28); "

  • 0
    Intellectual 560 points

    I send the patterns of transmision that the datasheet propouse

    Write function

    Read Function

    The value of SAD+W and SAD+R is determined by this table. I use 0xD4h and 0xD5h

  • 0 in reply to sanchezbjc_fi-iee
    TI__Guru**** 244400 points

    Hello Sanchezbjc,

    The Slave Address that is written to the master is left shifted by the API to accommodate the R/W bit. So the actual SA shoyld be SAD[6:0] and not SAD+R/W

    In other words use the value 0x6A for Write and Read.

    Regards

    Amit

  • 0 in reply to Amit Ashara
    Intellectual 560 points

    Thanks Amit, I change the value and the signal in oscillospe is correct, I can not read well the sensor 0xFFh Because the data is, but I will continue working

    I see a error in the initialization of sensor, I will correct 

  • 0 in reply to sanchezbjc_fi-iee
    TI__Guru**** 244400 points

    Hello Sanchez,

    The TM4C I2C Master uses the 7:1 of the Slave Address for some devices in which the manufaturer adds the RW bit also to the Slave Address.

    So in summary, when the Device address is specified as a 8-bit value consisting of Slave Address+R/W then right shift the value and use the same in hex notation for TM4C I2C.

    Regards

    Amit

  • 0 in reply to Amit Ashara
    Intellectual 560 points

    Hello Amit,

    The problem is solved, Thanks for your help

    I send the image with the signal of the correct transmission

    Axis X

  • 0 in reply to sanchezbjc_fi-iee
    TI__Guru**** 244400 points

    Hello Sanchez,

    What was the final issue and it's resolution? Our forum would appreciate such info for future users.

    Regards

    Amit

  • 0 in reply to Amit Ashara
    Intellectual 560 points

    Hello Amit,

    Well, the solution was to use the value of 0x6Ah as slave address for writing and reading.

    A new problem arose, since he could not read data display and were sent by UART.The solution was to remove the following statement in the code: 

    I2CMasterEnable(I2C0_BASE);

    Apparently there was a conflict and could not send data over the UART, but to eliminate it, the data is displayed on the terminal correctly.
     
    These are the functions which already I have a correct reading of the sensor:
     

    void L3gd20_Init(void)
    {
    I2CMasterSlaveAddrSet(I2C0_BASE,0x6A,false);
    I2CMasterDataPut(I2C0_BASE, 0x20);

    I2CMasterControl(I2C0_BASE, I2C_MASTER_CMD_BURST_SEND_START);
    while(I2CMasterBusy(I2C0_BASE));
    SysCtlDelay(10);

    I2CMasterDataPut(I2C0_BASE, 0x0F);
    I2CMasterControl(I2C0_BASE, I2C_MASTER_CMD_BURST_SEND_FINISH);
    while(I2CMasterBusy(I2C0_BASE));
    }


    uint8_t ByteReadL3GD20(uint32_t address)
    {
    uint8_t addr,dato;
    addr=address;

    I2CMasterSlaveAddrSet(I2C0_BASE, 0x6A ,false);

    I2CMasterDataPut(I2C0_BASE, addr);

    I2CMasterControl(I2C0_BASE, I2C_MASTER_CMD_BURST_SEND_START);
    while(I2CMasterBusy(I2C0_BASE));

    I2CMasterSlaveAddrSet(I2C0_BASE, 0x6A, true);

    I2CMasterControl(I2C0_BASE, I2C_MASTER_CMD_SINGLE_RECEIVE);

    while(I2CMasterBusy(I2C0_BASE));

    return I2CMasterDataGet(I2C0_BASE);
    }


    Thanks for your help
    Juan Carlos