MSP432E401Y: I2C going into illegal state after sending BURST_START command

Hi Raj,

Can you share a little bit of your code that configures the I2C operation?

Hi Dennis,

I am sharing the initialization and send functions for I2C0 as below, please let me know whats making the bus to go into illegal state and why I2CMDR register is not initialized with the data to be sent. The code has been taken from the examples provided in the SDK. Even we tried to execute the SDK code directly without any modification but the bus goes into illegal state immediately after sending BURST_START command.

void iot_i2c_init()
{

uint32_t systemClock;

/* Configure the system clock for 120 MHz */
systemClock = MAP_SysCtlClockFreqSet((SYSCTL_XTAL_25MHZ | SYSCTL_OSC_MAIN |
SYSCTL_USE_PLL | SYSCTL_CFG_VCO_480),
120000000);

/* Enable clocks to GPIO Port B and configure pins as Output */
MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);
while(!(MAP_SysCtlPeripheralReady(SYSCTL_PERIPH_GPIOB)))
{
}

/* Enable clocks to GPIO Port B and configure pins as I2C */
MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOB);
while(!(MAP_SysCtlPeripheralReady(SYSCTL_PERIPH_GPIOB)))
{
}

MAP_GPIOPinConfigure(GPIO_PB2_I2C0SCL);
MAP_GPIOPinConfigure(GPIO_PB3_I2C0SDA);
MAP_GPIOPinTypeI2C(GPIO_PORTB_BASE, GPIO_PIN_3);
MAP_GPIOPinTypeI2CSCL(GPIO_PORTB_BASE, GPIO_PIN_2);

/* Since there are no board pull up's we shall enable the weak internal
* pull up */
GPIOB->PUR |= (GPIO_PIN_3 | GPIO_PIN_2);

/* Initialize the slave address with default transmit mode */
//MAP_I2CMasterSlaveAddrSet(I2C0_BASE, SLAVE_ADDRESS|I2C_WR_MODE, false);

/* Enable the clock to I2C-0 module and configure the I2C Master */
MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_I2C0);
while(!(MAP_SysCtlPeripheralReady(SYSCTL_PERIPH_I2C0)))
{
}

/* Configure the I2C Master in standard mode and enable interrupt for Data
* completion, NAK and Stop condition on the bus */
MAP_I2CMasterInitExpClk(I2C0_BASE, systemClock, false);
MAP_I2CMasterIntEnableEx(I2C0_BASE, I2C_MASTER_INT_NACK |
I2C_MASTER_INT_STOP |
I2C_MASTER_INT_DATA);

/* Initialize the state of the I2C Master */
setI2CState = I2C_MASTER_IDLE;

}

void i2c_send(uint8_t data)
{

uint32_t int_status = 0;

/* Enable I2C-0 master controller */
MAP_I2CMasterEnable(I2C0_BASE);

/* initialize the slave address with transmit mode */
MAP_I2CMasterSlaveAddrSet(I2C0_BASE, SLAVE_ADDRESS>>1, false);

/* write data to buffer */
MAP_I2CMasterDataPut(I2C0_BASE, data);

/* generate start condition and wait for the bus */
MAP_I2CMasterControl(I2C0_BASE, I2C_MASTER_CMD_BURST_SEND_START);

/* wait until bus is free */
while(MAP_I2CMasterBusy(I2C0_BASE));

/* force stop and wait for the condition */
MAP_I2CMasterControl(I2C0_BASE, I2C_MASTER_CMD_BURST_SEND_FINISH);
do {
int_status = MAP_I2CMasterIntStatus(I2C0_BASE, true);
}while((int_status & I2C_MASTER_INT_STOP) == I2C_MASTER_INT_STOP);

/* clear all interrupt flags */
MAP_I2CMasterIntClearEx(I2C0_BASE, int_status);

/* disable the master */
MAP_I2CMasterDisable(I2C0_BASE);

}

Please anybody help on this issue its urgent for our project. Why I2C bus is not working? Is there any issue with the code?

We have tried to checked with two MSPs also one as master and another as slave as given in the SDK which is also not working and bus is going into illegal state.

Please help...

Hi Raj,

I really apologize for the delay.  I had to order an MSP432E401 launchpad in order to follow along with what you are seeing.  I receive it tomorrow.

In the mean time do you have a logic probe or oscilloscope and capture an image of the I2C bus traffic when you see the failure?