I2C issue (CC3200)

Do you have proper pullup resistors on your I2C lines?

Hello Steve,

Resistors on pull up are 1K.

The picture of scope attached (when we send "readreg" command to accelerometer using TI-RTOS).

Top (yellow) signal is DATA and lower is CLOCK (blue).

What do you think about it?

Those edges don't look right at all.  It looks like you may have a ton of capacitance on your lines.  Do you have a lot of devices connected to the I2C port?  IME 1K is probably too low for a pullup value, but your edges clearly aren't moving fast enough.  I'd try to figure out why your lines have so much capacitance before I do anything else.

Are you trying to run 100KHz or 400KHz?  I recommend starting with 100KHz to keep it simpler.

There is only a one device (accelerometer) connected on address 0x1C.

I tried 100KHz.

I do not see the address is transfered. 

One more picture attached: 

Hi Gleb,

Did you try running the i2c_demo example code?
Besides the pin muxing which looks ok, did you remember to initialize the I2C, by calling to I2C_IF_Open(I2C_MASTER_MODE_FST) ?
Can you please provide a code snippet of your entire I2C handling, including init, read\write?

Thanks,
Alon

Hi Alon,

1. Yes we tried i2c_demo example code, but there were no clock signal on I2C bus.
2. We are using TI-RTOS (according to example i2ctmp006_CC3200) and here is our code:

uint8_t txBuffer[1];
uint8_t rxBuffer[2];
I2C_Handle i2c;
I2C_Params i2cParams;
I2C_Transaction i2cTransaction;

/ Create I2C for usage /
I2C_Params_init(&i2cParams);
i2cParams.bitRate = I2C_100kHz;
i2c = I2C_open(Board_I2C0, &i2cParams);
if (i2c == NULL) {
System_abort("Error Initializing I2C\n");
}
else {
System_printf("I2C Initialized!\n");
}

txBuffer[0] = 0x0d; // Who i am register of accelerometer
i2cTransaction.slaveAddress = 0x1c; // Slave address of accelerometer
i2cTransaction.writeBuf = txBuffer;
i2cTransaction.writeCount = 1;
i2cTransaction.readBuf = rxBuffer;
i2cTransaction.readCount = 1;

if (I2C_transfer(i2c, &i2cTransaction)) {
System_printf("Value %d\n", rxBuffer[0]);
}

Pinmux file:
MAP_PRCMPeripheralClkEnable(PRCM_I2CA0, PRCM_RUN_MODE_CLK);
MAP_PinTypeI2C(PIN_05, PIN_MODE_5);
MAP_PinTypeI2C(PIN_06, PIN_MODE_5);

I've got this working on my cc3200 + ti-rtos:

pinmux.c

...

MAP_PRCMPeripheralClkEnable(PRCM_I2CA0, PRCM_RUN_MODE_CLK);

/*I2C*/
	//
	// Configure PIN_01 for I2C0 I2C_SCL
	//
	MAP_PinTypeI2C(PIN_01, PIN_MODE_1);

	//
	// Configure PIN_02 for I2C0 I2C_SDA
	//
	MAP_PinTypeI2C(PIN_02, PIN_MODE_1);

i2c.c

...

/*
 *  ======== I2C_init ========
 */
void I2C_Helper_init(unsigned int indexI2C, float freq )
{
	    uint8_t newmode;
	    uint8_t oldmode;

	    i2cTransaction.slaveAddress = 0x40; //Slave address

	    /* Create I2C for usage */
	    I2C_Params_init(&i2cParams);
	    i2cParams.bitRate = I2C_400kHz;
	    i2c = I2C_open(indexI2C, &i2cParams);
	    if (i2c == NULL) {
	        System_abort("Error Initializing I2C\n");
	    }
	    else {
	         System_printf("I2C Initialized!\n");
	         System_flush();
	    }
}




/*
 *  ======== I2C_set_Data ========
 */

void I2C_set_Data(uint8_t channel, uint16_t value)
{
	txBuffer[0] = (0x6+4*channel); //LED0_ON_L at port number
	txBuffer[1] = 0x0; //on
	txBuffer[2] = txBuffer[1]>>8; //on
	txBuffer[3] = value; //off
	txBuffer[4] = value>>8;//off

}




/*
 *  ======== I2C_send_and_receive_Data ========
 */
void I2C_transfer_Data(void)
{
	i2cTransaction.writeBuf = txBuffer;
	i2cTransaction.writeCount = 5;
	i2cTransaction.readBuf = rxBuffer;
	i2cTransaction.readCount = 0;

	 if (I2C_transfer(i2c, &i2cTransaction)) {
		    	
		}
		else {
			  System_printf("I2C Bus fault\n");
			  System_flush();
			  }

	/* Deinitialized I2C */
//	I2C_close(i2c);
//	System_printf("I2C closed!\n");
//	System_flush();

}

Don't forget to activate the i2c drivers in your ti-rtos config.

Maybe it helps