TMS320F28379D: I2C without interrupts regarding the FIFO

The SME is currently unavailable to respond to this thread. Kindly expect a response in the next 2-3 days.

Hi Balaji,

It looks the data is being overwritten in the I2C buffers. You can verify this by checking what the data is in both the buffers and on the data line itself between the first 16 bytes and the second 11 bytes which should show you if the first 16 bytes are transmitted / received properly. As for the data you have not labelled in the second image, is this data from the first transmission and/or some other known values or are they random? Are the interrupts being triggered / working correctly? When the I2C is in FIFO mode, the I2CCNT is not used but rather the TXFFST.

I2C buffers need to be cleared before more data is written / read from and this information is in the TRM as well as software examples itself in more detail. Please precisely identify where the issue occurs in software and the steps taken for resolution, so I can better assist.

Best Regards,

Aishwarya

I could get the code working following the examples you have mentioned. The code that is sending the full 27 bytes is pasted below.

The statement 

    while(I2C_getTxFIFOStatus(I2CA_BASE)!=I2C_FIFO_TX0){}//Wait till FIFO remaining bits is zero?

ensures that the transmit FIFO gets empty before going for the next 11 bytes.

By the way, simply putting a delay of 100ms after the the I2C_sendStartCondition() function call , before the

 I2C_sendStopCondition() also works...

Code:

void init_i2c_module(){

    // https://software-dl.ti.com/C2000/docs/C2000_driverlib_api_guide/f2837xd/html/modules/i2c.html#

    I2C_disableModule(I2CA_BASE);//Before initializing the I2C module, the user first must put the module into the reset state

    I2C_initMaster(I2CA_BASE, DEVICE_SYSCLK_FREQ, 10000, I2C_DUTYCYCLE_50);//the user must then call I2C_initMaster() which will configure the rate and duty cycle of the master clock.

    I2C_setDataCount(I2CA_BASE, 16);// Set data count must be before enable fifo

    I2C_enableFIFO(I2CA_BASE);

    I2C_setConfig(I2CA_BASE, I2C_MASTER_SEND_MODE);//I2C_setConfig() should be called to configure the behavior of the module

    I2C_setSlaveAddress(I2CA_BASE, 0x3C);

    I2C_enableModule(I2CA_BASE);



    I2C_putData(I2CA_BASE,0x00);// First byte: Command identifier 0x00 is the first byte, remaining 15 bytes are put in the FIFO using for loop below

    for (iter=0;iter<=14;iter++)// Remaining 15 bytes of the init data to fill up the FIFO

    {

        I2C_putData(I2CA_BASE,s_oled128x64_initData[iter]);

    }

    I2C_sendStartCondition(I2CA_BASE);

    while(I2C_getTxFIFOStatus(I2CA_BASE)!=I2C_FIFO_TX0){}//Wait till FIFO remaining bits is zero?

    //    DEVICE_DELAY_US(10000);

    I2C_sendStopCondition(I2CA_BASE);



    // Of the total 27 bytes, 16 sent earlier, 11 more are pending.

    I2C_setDataCount(I2CA_BASE, 11);

    for (iter=15;iter<=24;iter++)// 10 bytes from initdata populated in the FIFO using for loop

    {

        I2C_putData(I2CA_BASE,s_oled128x64_initData[iter]);

    }

    I2C_putData(I2CA_BASE,0xA5);// Last command byte to light up the screen is the 27th byte.

    I2C_sendStartCondition(I2CA_BASE);//A start condition can be sent by a master using I2C_sendStartCondition()

    while(I2C_getTxFIFOStatus(I2CA_BASE)!=I2C_FIFO_TX0){}//Wait till FIFO remaining bits is zero?

    I2C_sendStopCondition(I2CA_BASE);//A start condition can be sent by a master using I2C_sendStartCondition()

}