CCS/MSP430FR6989: I2C sample code using MSP430Ware MSP430FR5xx_6xx Driverlib

Dear Ryan

The BME280 is working perfectly fine with the same launchpad with energia code. I am have trouble with this code in CCS. The energia code is working even when I import to CCS. After running many times, the code worked only once. Presently I am using 10K pullup resisters and I tried 4.7K resistors also. Both were working with energia but not with this code. I also tried below code with interrupts from the examples you mentioned but it getting stuck at __bic_SR_register_on_exit(LPM0_bits); I am not able get the TXIFG0 interrupt.

Sorry I do not have an oscilloscope I also dont know how to use it. I am a medical science doctor working on a pollution sensing project.

Please see the code below and let me know what I am doing wrong here. I has taken me 2 weeks to get to this level : )

I have not added any restart for Receive. This code itself is getting stuck at the GIE.

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#include <msp430fr6989.h>

#define BME280_ADDRESS 0x77
#define CHIP_ADDRESS 0xd0

volatile unsigned char TXByteCtr;
unsigned char RX_Data;

int main(void)
{
  WDTCTL = WDTPW | WDTHOLD;
  P1SEL0 |= BIT6 | BIT7;
  PM5CTL0 &= ~LOCKLPM5;
  UCB0CTLW0 = UCSWRST;                                // Enable SW reset
  UCB0CTLW0 |= UCMODE_3 | UCMST | UCSSEL__SMCLK;      // I2C Master, synchronous mode
  UCB0BRW = 0x8;                                     // fSCL = SMCLK/12 = ~100kHz
  UCB0CTLW0 &= ~UCSWRST;                             // Clear SW reset, resume operation
  UCB0IE |= UCTXIE0 | UCRXIE0 | UCNACKIE;             //Enable RX and TX interrupt

  while(1)
  {
      __delay_cycles(1000);                   // Delay between transmissions
      UCB0I2CSA = BME280_ADDRESS;    // configure slave address
      TXByteCtr = 1;                          // Load TX byte counter
      while (UCB0CTLW0 & UCTXSTP);            // Ensure stop condition got sent

      UCB0CTLW0 |= UCTR | UCTXSTT;            // I2C TX, start condition

      __bis_SR_register(LPM0_bits | GIE);
  }
}

#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector = USCI_B0_VECTOR
__interrupt void USCI_B0_ISR(void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(USCI_B0_VECTOR))) USCI_B0_ISR (void)
#else
#error Compiler not supported!
#endif
{
    switch(__even_in_range(UCB0IV, USCI_I2C_UCBIT9IFG))
    {
      case USCI_NONE:          break;         // Vector 0: No interrupts
      case USCI_I2C_UCALIFG:   break;         // Vector 2: ALIFG
      case USCI_I2C_UCNACKIFG:                // Vector 4: NACKIFG
        UCB0CTLW0 |= UCTXSTT;                 // resend start if NACK
        break;
      case USCI_I2C_UCSTTIFG:  break;         // Vector 6: STTIFG
      case USCI_I2C_UCSTPIFG:  break;         // Vector 8: STPIFG
      case USCI_I2C_UCRXIFG3:  break;         // Vector 10: RXIFG3
      case USCI_I2C_UCTXIFG3:  break;         // Vector 12: TXIFG3
      case USCI_I2C_UCRXIFG2:  break;         // Vector 14: RXIFG2
      case USCI_I2C_UCTXIFG2:  break;         // Vector 16: TXIFG2
      case USCI_I2C_UCRXIFG1:  break;         // Vector 18: RXIFG1
      case USCI_I2C_UCTXIFG1:  break;         // Vector 20: TXIFG1
      case USCI_I2C_UCRXIFG0:  break;         // Vector 22: RXIFG0
      case USCI_I2C_UCTXIFG0:                 // Vector 24: TXIFG0
        if (TXByteCtr)                        // Check TX byte counter
        {
          UCB0TXBUF = CHIP_ADDRESS;      // Load TX buffer
          TXByteCtr--;                        // Decrement TX byte counter
        }
        else
        {
          UCB0CTLW0 |= UCTXSTP;               // I2C stop condition
          UCB0IFG &= ~UCTXIFG;                // Clear USCI_B0 TX int flag
          __bic_SR_register_on_exit(LPM0_bits); // Exit LPM0
        }
        break;
      default: break;
    }
  }

Ryan

What perplexes me is the fact that it Launchpad with 10K pullups is working in energia while it is not in CCS? Is there any additional project/build configuration the I need to do in CCS?

Regards
Dr. Vijay

The 10k resistors on my LaunchPad do work in CCS. What are your IDE and compiler versions?  You can try sending me your CCS project files to review if you think it will be of any use.

Regards,
Ryan