TCA9534: Unable to Drive the IO Expander TCA9534PWR from microcontroller TM4C1294ncpdt using I2C4

void I2c_init()
{
    //#######INITIALIZATION############

            // The I2C3 peripheral must be enabled before use.
            SysCtlPeripheralEnable(SYSCTL_PERIPH_I2C3);
            SysCtlPeripheralReset(SYSCTL_PERIPH_I2C3);

            // The I2C4 peripheral must be enabled before use.
            SysCtlPeripheralEnable(SYSCTL_PERIPH_I2C4);
            SysCtlPeripheralReset(SYSCTL_PERIPH_I2C4);

            SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOK);

            GPIOPinConfigure(GPIO_PK4_I2C3SCL);
            GPIOPinConfigure(GPIO_PK5_I2C3SDA);

            GPIOPinTypeI2CSCL(GPIO_PORTK_BASE, GPIO_PIN_4);
            GPIOPinTypeI2C(GPIO_PORTK_BASE, GPIO_PIN_5);
            I2CMasterInitExpClk(I2C3_BASE, g_ui32SysClock, false);
           // I2CMasterSlaveAddrSet(I2C3_BASE, SLAVE_ADDRESS , false); // slave address to 0x20
            I2CMasterEnable(I2C3_BASE);



            GPIOPinConfigure(GPIO_PK6_I2C4SCL);
            GPIOPinConfigure(GPIO_PK7_I2C4SDA);

            GPIOPinTypeI2CSCL(GPIO_PORTK_BASE, GPIO_PIN_6);
            GPIOPinTypeI2C(GPIO_PORTK_BASE, GPIO_PIN_7);
            I2CMasterInitExpClk(I2C4_BASE, g_ui32SysClock, false);
            I2CMasterSlaveAddrSet(I2C4_BASE, 0x27 , false); // slave address to 0x27
            I2CMasterEnable(I2C4_BASE);

            I2CMasterGlitchFilterConfigSet(I2C3_BASE, I2C_MASTER_GLITCH_FILTER_2);
            I2CMasterGlitchFilterConfigSet(I2C4_BASE, I2C_MASTER_GLITCH_FILTER_2);

      }

void I2CSend4(uint8_t slave_addr, uint8_t num_of_args, ...)
{
    uint8_t i =0;
    // Tell the master module what address it will place on the bus when
    // communicating with the slave.
    I2CMasterSlaveAddrSet(I2C4_BASE, slave_addr, false);

    //stores list of variable number of arguments
    va_list vargs;

    //specifies the va_list to "open" and the last fixed argument
    //so vargs knows where to start looking
    va_start(vargs, num_of_args);

    //put data to be sent into FIFO
    I2CMasterDataPut(I2C4_BASE, va_arg(vargs, uint32_t));

    //if there is only one argument, we only need to use the
    //single send I2C function
    if(num_of_args == 1)
    {
        //Initiate send of data from the MCU
        I2CMasterControl(I2C4_BASE, I2C_MASTER_CMD_SINGLE_SEND);

        // Wait until MCU is done transferring.
        while(I2CMasterBusy(I2C4_BASE));

        //"close" variable argument list
        va_end(vargs);
    }

    //otherwise, we start transmission of multiple bytes on the
    //I2C bus
    else
    {
        //Initiate send of data from the MCU
        I2CMasterControl(I2C4_BASE, I2C_MASTER_CMD_BURST_SEND_START);

        // Wait until MCU is done transferring.
        while(I2CMasterBusy(I2C4_BASE));

        //send num_of_args-2 pieces of data, using the
        //BURST_SEND_CONT command of the I2C module
        for( i = 1; i < (num_of_args - 1); i++)
        {
            //put next piece of data into I2C FIFO
            I2CMasterDataPut(I2C4_BASE, va_arg(vargs, uint32_t));
            //send next data that was just placed into FIFO
            I2CMasterControl(I2C4_BASE, I2C_MASTER_CMD_BURST_SEND_CONT);

            // Wait until MCU is done transferring.
            while(I2CMasterBusy(I2C4_BASE));
        }

        //put last piece of data into I2C FIFO
        I2CMasterDataPut(I2C4_BASE, va_arg(vargs, uint32_t));
        //send next data that was just placed into FIFO
        I2CMasterControl(I2C4_BASE, I2C_MASTER_CMD_BURST_SEND_FINISH);
        // Wait until MCU is done transferring.
        while(I2CMasterBusy(I2C4_BASE));

        //"close" variable args list
        va_end(vargs);
    }
}
//read specified register on slave device
uint32_t I2CReceive4(uint32_t slave_addr, uint8_t reg)
{
    //specify that we are writing (a register address) to the
    //slave device
    I2CMasterSlaveAddrSet(I2C4_BASE, slave_addr, false);

    //specify register to be read
    I2CMasterDataPut(I2C4_BASE, reg);

    //send control byte and register address byte to slave device
    I2CMasterControl(I2C4_BASE, I2C_MASTER_CMD_BURST_SEND_START);

    //wait for MCU to finish transaction
    while(I2CMasterBusy(I2C4_BASE));

    //specify that we are going to read from slave device
    I2CMasterSlaveAddrSet(I2C4_BASE, slave_addr, true);

    //send control byte and read from the register we
    //specified
    I2CMasterControl(I2C4_BASE, I2C_MASTER_CMD_SINGLE_RECEIVE);

    //wait for MCU to finish transaction
    while(I2CMasterBusy(I2C4_BASE));

    //return data pulled from the specified register
    return I2CMasterDataGet(I2C4_BASE);
}

void Set_output()
{
   I2CSend4(SLAVE_DR1, 2, 0x03, 0x00); 
}

void Write_output(uint8_t pin)
{
   I2CSend4(SLAVE_DR1,2, 0x01, pin);
}

These I²C waveforms look OK.

What is the problem that you're seeing?

Hi Ramesh,

You write to the configuration register to set all p-ports to outputs, but do you write to the output port register as well to toggle between high and low logic levels? 

Regards,

Tyler