[Mspgcc-users] I2C Initialisation Problem

[Ciaran Davies]

Hi all,

I've been attempting to get I2C working on a msp430xG4618 configuration 
without any success. Examples are hard to come by for mspgcc tool chain.
Here's my init sequence:
     WDTCTL = WDTPW + WDTHOLD;                 // Stop WDT
     P3SEL |= 0x06;                                                // 
Assign I2C pins to USCI_B0
     UCB0CTL1 |= UCSWRST;                      // Enable SW reset
     UCB0CTL0 = UCMST + UCMODE_3 + UCSYNC;     // I2C Master, 
synchronous mode

     UCB0CTL1 = UCSSEL_2 + UCSWRST;            // Use SMCLK, keep SW reset

     UCB0BR0 = 40;                             // fSCL = SMCLK/11  ~ 100kHz
     UCB0BR1 = 0;
     UCA0MCTL = 0x04;                           // 4Mhz Modulation

     UCB0I2CSA = 0x48;                         // Slave Address is 048h

     UCB0CTL1 &= ~UCSWRST;                     // Clear SW reset, 
resume operation
     IE2 |= UCB0RXIE | UCB0TXIE;               // Enable RX interrupt

     UCB0CTL1 |= UCTXSTT;                    // I2C start condition

   
and the ISR:

interrupt(USCIRX_VECTOR) USCIAB0TX_ISR(void)
{
   // Some test code here...
}


I'm getting no interrupts generated and putting a scope on the I2C data 
line or clock line shows no activity at all.
Any help would be greatly appreciated as I've spent a lot of time on this.
Thanks,
Ciaran