CCS/MSP432P401R: I2C in CCS is different from Keil

Tom Woo

Part Number: MSP432P401R
Other Parts Discussed in Thread: TCA9535

Tool/software: Code Composer Studio

For some reason, i have to change the IDE from keil to ccs, and i found that when i use software i2c in keil ,after one read process,it will halt long time,but in ccs it didn't. And the ccs may cause read/write error because the break between two read process is to short.

following image show the problem:

keil:

it took over 100ms after first read.

first read:

second read:

ccs:

it did the second read right after first read,it only break few time i set to delay.

i don't konw why,should i set some compile para in ccs or what? thanks.

over 8 years ago

0 Bob Landers over 8 years ago

TI__Expert 8510 points

Can you send the master/slave software you are using, or let me know which example this is if you are using an example from the SimpleLink SDK?

0 Tom Woo over 8 years ago in reply to Bob Landers

Prodigy 180 points

hi Bob, i'm using io simulate i2c like this

void I2C_SendByte(C_U32 a_u32SclPort, C_U32 a_u32SclPin, C_U32 a_u32SdaPort, C_U32 a_u32SdaPin, C_U8 a_u8Data) 
{
    C_U8 i = 0;

    SCL_LOW(a_u32SclPort, a_u32SclPin);

    for ( i = 0; i < 8; i ++)
    {
        (a_u8Data & 0x80) ? SDA_HIGH(a_u32SdaPort, a_u32SdaPin) : SDA_LOW(a_u32SdaPort, a_u32SdaPin);
        Delay(DELAY_MS); // ***
        SCL_HIGH(a_u32SclPort, a_u32SclPin);
        Delay(DELAY_MS);
        Delay(DELAY_MS); // ***
        SCL_LOW(a_u32SclPort, a_u32SclPin);
        Delay(DELAY_MS);
        a_u8Data <<= 1;
    }
}

static void TCA9535_Write(ST_TCA9535* a_pstTCA9535, C_U8 a_u8RegAddr, C_U8 a_u8RegData)
{
   
	I2C_Start(SCL_PORT, SCL_PIN, SDA_PORT, SDA_PIN);

   
	I2C_SendByte(SCL_PORT, SCL_PIN, SDA_PORT, SDA_PIN, a_pstTCA9535->m_DevAddrW);
	if (!I2C_CheckAck(SCL_PORT, SCL_PIN, SDA_PORT, SDA_PIN))
    {
        I2C_Stop(SCL_PORT, SCL_PIN, SDA_PORT, SDA_PIN);
        Printf("error: %s, %d,addr:%x\r\n", __FILE__, __LINE__,a_pstTCA9535->m_DevAddrR>>1);
        return ;
    }

   
    I2C_SendByte(SCL_PORT, SCL_PIN, SDA_PORT, SDA_PIN, a_u8RegAddr);
	if (!I2C_CheckAck(SCL_PORT, SCL_PIN, SDA_PORT, SDA_PIN))
    {
        I2C_Stop(SCL_PORT, SCL_PIN, SDA_PORT, SDA_PIN);
        Printf("error: %s, %d,addr:%x\r\n", __FILE__, __LINE__,a_pstTCA9535->m_DevAddrR>>1);
        return ;
    }

    /* Data */
    I2C_SendByte(SCL_PORT, SCL_PIN, SDA_PORT, SDA_PIN, a_u8RegData);
	if (!I2C_CheckAck(SCL_PORT, SCL_PIN, SDA_PORT, SDA_PIN))
    {
        I2C_Stop(SCL_PORT, SCL_PIN, SDA_PORT, SDA_PIN);
        Printf("error: %s, %d,addr:%x\r\n", __FILE__, __LINE__,a_pstTCA9535->m_DevAddrR>>1);
        return ;
    }

   
	I2C_Stop(SCL_PORT, SCL_PIN, SDA_PORT, SDA_PIN);
}

0 Bob Landers over 8 years ago in reply to Tom Woo

TI__Expert 8510 points

Is there a reason you are trying to do this with a Software-driven approach rather than using the I2C peripheral and driverlib code? I would first look at our I2C examples in Resource Explorer. I would start with the master/slave pair below:

i2c_master_w_multibyte-slave_code

i2c_master_w_multibyte-master_code

Regards,

Bob

0 Tom Woo over 8 years ago in reply to Bob Landers

Prodigy 180 points

well,first i try to use the demo code in light sensor to read data from TCA9535,like this

const eUSCI_I2C_MasterConfig i2cConfig =
{
        EUSCI_B_I2C_CLOCKSOURCE_SMCLK,          // SMCLK Clock Source
        24000000,                               // SMCLK = 48MHz
        EUSCI_B_I2C_SET_DATA_RATE_100KBPS,      // Desired I2C Clock of 100khz
        0,                                      // No byte counter threshold
        EUSCI_B_I2C_NO_AUTO_STOP                // No Autostop
};

static void TCA9535_Write(ST_TCA9535* a_pstTCA9535, C_U8 a_u8RegAddr, C_U8 a_u8RegData)
{

/* Specify slave address for I2C */
I2C_setSlaveAddress(EUSCI_B3_BASE,
	(a_pstTCA9535->m_DevAddr));
  
/* Enable and clear the interrupt flag */
I2C_clearInterruptFlag(EUSCI_B3_BASE,
	EUSCI_B_I2C_TRANSMIT_INTERRUPT0 + EUSCI_B_I2C_RECEIVE_INTERRUPT0);

/* Set master to transmit mode PL */
   I2C_setMode(EUSCI_B3_BASE,
	   EUSCI_B_I2C_TRANSMIT_MODE);
 
   /* Clear any existing interrupt flag PL */
   I2C_clearInterruptFlag(EUSCI_B3_BASE,
	   EUSCI_B_I2C_TRANSMIT_INTERRUPT0);

   /* Wait until ready to write PL */
   while (I2C_isBusBusy(EUSCI_B3_BASE));
 

   /* Initiate start and send first character */
   I2C_masterSendMultiByteStart(EUSCI_B3_BASE,
	   a_u8RegAddr);

   while(!I2C_getInterruptStatus(EUSCI_B3_BASE,
        EUSCI_B_I2C_STOP_INTERRUPT));
	 
   I2C_masterSendMultiByteFinish(EUSCI_B3_BASE,
	  a_u8RegData);
	  while(!I2C_getInterruptStatus(EUSCI_B3_BASE,
        EUSCI_B_I2C_STOP_INTERRUPT));
}

static void TCA9535_Read(ST_TCA9535* a_pstTCA9535, C_U8 a_u8RegAddr, C_U8* a_u8RegData)
{
	
	/* Specify slave address for I2C */
	I2C_setSlaveAddress(EUSCI_B3_BASE,
		(a_pstTCA9535->m_DevAddr));
	
	/* Enable and clear the interrupt flag */
	I2C_clearInterruptFlag(EUSCI_B3_BASE,
		EUSCI_B_I2C_TRANSMIT_INTERRUPT0 + EUSCI_B_I2C_RECEIVE_INTERRUPT0);


    /* Set master to transmit mode PL */
    I2C_setMode(EUSCI_B3_BASE,
        EUSCI_B_I2C_TRANSMIT_MODE);
 
    /* Clear any existing interrupt flag PL */
    I2C_clearInterruptFlag(EUSCI_B3_BASE,
        EUSCI_B_I2C_TRANSMIT_INTERRUPT0);

    /* Wait until ready to write PL */
    while (I2C_isBusBusy(EUSCI_B3_BASE));

    /* Initiate start and send first character */
    I2C_masterSendMultiByteStart(EUSCI_B3_BASE, a_u8RegAddr);

    /* Wait for TX to finish */
    while(!(I2C_getInterruptStatus(EUSCI_B3_BASE,
        EUSCI_B_I2C_TRANSMIT_INTERRUPT0)));

    /* Initiate stop only */
    I2C_masterSendMultiByteStop(EUSCI_B3_BASE);

    /* Wait for Stop to finish */
    while(!I2C_getInterruptStatus(EUSCI_B3_BASE,
        EUSCI_B_I2C_STOP_INTERRUPT));

    /*
     * Generate Start condition and set it to receive mode.
     * This sends out the slave address and continues to read
     * until you issue a STOP
     */
		*a_u8RegData = I2C_masterReceiveSingleByte(EUSCI_B3_BASE);
    //I2C_masterReceiveStart(EUSCI_B3_BASE);

    /* Wait for RX buffer to fill */
  //  while(!(I2C_getInterruptStatus(EUSCI_B3_BASE,
       // EUSCI_B_I2C_RECEIVE_INTERRUPT0)));

    /* Receive second byte then send STOP condition */
   // *a_u8RegData = I2C_masterReceiveMultiByteFinish(EUSCI_B3_BASE);
	
}

void TCA9535_Init(ST_TCA9535* a_pstTCA9535, C_U8 a_u8DevAddr)
{
    a_pstTCA9535->m_DevAddrW = (a_u8DevAddr << 1) | 0; // Addr + Write
    a_pstTCA9535->m_DevAddrR = (a_u8DevAddr << 1) | 1; // Addr + Read
    a_pstTCA9535->m_DevAddr = a_u8DevAddr;
	
    GPIO_setAsPeripheralModuleFunctionOutputPin(
            SCL_PORT,
            SCL_PIN,
            GPIO_SECONDARY_MODULE_FUNCTION);

    GPIO_setAsPeripheralModuleFunctionOutputPin(
            SDA_PORT,
            SDA_PIN,
            GPIO_SECONDARY_MODULE_FUNCTION);

			/* Initialize USCI_B0 and I2C Master to communicate with slave devices*/
	  I2C_initMaster(EUSCI_B3_BASE, &i2cConfig);
	
	  /* Disable I2C module to make changes */
	  I2C_disableModule(EUSCI_B3_BASE);
	
	  /* Enable I2C Module to start operations */ 
	 I2C_enableModule(EUSCI_B3_BASE);
	  /* Select I2C function for I2C_SCL(P6.5) & I2C_SDA(P6.4) */
}

it will stuck in

while (I2C_isBusBusy(EUSCI_B3_BASE));
because the UCBBUSY is alwasy set.
And i found that UCBBUSY is set right after i do I2C_enableModule(EUSCI_B3_BASE);
and never reset, but i haven't begun to send a byte.

the second reason is because i'm using another i2c to communicate with a device that will switch scl and sda, that means, if i read or write error, i will switch scl and sda and try again,
so i'm using software driven.And i use this in communicating with TCA9535 too for convenience.

0 Bob Landers over 8 years ago in reply to Tom Woo

TI__Expert 8510 points

It looks like this issue was answered in this post, so closing the thread here.

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CCS/MSP432P401R: I2C in CCS is different from Keil