MSP430FR6989: I2C getting stuck at UCBBUSY

Vijay Kolaventy

Part Number: MSP430FR6989

The I2C reads and writes fine until I use the UART_A0 and connect to server through GPRS modem on TCP. I am using the I2C to read from BME280 and send the data to the server every 10 secs. It works the first time and them gets stuct in I2C read near the line while(UCB1STAT & UCBBUSY);. If I comment this line, it get stuck at next the while(UCBICTLW0 & UCTXSTT).

unsigned int I2C_Read(unsigned int slv_addr, unsigned int reg_addr, unsigned int len, char *arr)
{
    unsigned int i = 0;

    while(UCB1STAT & UCBBUSY);
    UCB1I2CSA = slv_addr;
    UCB1CTLW0 |= UCTR | UCTXSTT;

    while(UCB1CTLW0 & UCTXSTT);
    UCB1TXBUF = reg_addr;
    while(!(UCB1IFG & UCTXIFG0));

    UCB1CTLW0 &= ~UCTR;
    UCB1CTLW0 |= UCTXSTT;

    while(UCB1CTLW0 & UCTXSTT);

    for(i = 0; i < len; i++)
    {
        if(i == len - 1)
        {
            UCB1CTLW0 |= UCTXSTP;
        }
        while(!(UCB1IFG & UCRXIFG0));
        arr[i] = UCB1RXBUF;
    }

    while(UCB1CTLW0 & UCTXSTP);

    return(i);
}

The same program works fine if I dont use the GPRS. Please help.

Regards

Vijay

over 4 years ago

0 Yiding Luo over 4 years ago

TI__Expert 5490 points

Hello Vijay,

Thanks for your post.

We will look into this and get back to you ASAP.

Thanks,

Yiding

0 Tyler Rothenberg over 4 years ago in reply to Yiding Luo

Prodigy 30 points

When you configured your I2C module, did you enter the reset mode at the start and exit at the end?

void Initialize_I2C(void)
{
    // Enter reset state before the configuration starts...
    UCB1CTLW0 |= UCSWRST;

    UCB1CTLW0 .....

    // Exit the reset mode
    UCB1CTLW0 &= ~UCSWRST;
}

0 David Schultz over 4 years ago

Guru 18885 points

Since you say it works unless you use UCA0, the first place I would look is the code for UCA0.

0 Vijay Kolaventy over 4 years ago in reply to David Schultz

Intellectual 870 points

I do not know what was the reason is but the same code is working now. Could be some loose wiring issue. But I checked that many times. I am not sure. Thanks for your time

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MSP430FR6989: I2C getting stuck at UCBBUSY