SCI FIFO interrupt doesn't work

I wanted to transmit data using SCI with interrupt.

What I currently have for the SCI initialization is:

SciaRegs.SCICCR.all = 0x0007; // 1 stop bit, no parity, 8 char bits

SciaRegs.SCICTL1.all = 0x0002; // Initialize SCI, enable TX

SciaRegs.SCICTL2.bit.TXINTENA = 1; // Enable TX interrupt

SciaRegs.SCIHBAUD = 0;

SciaRegs.SCILBAUD = 780; // 9603 baud rate

SciaRegs.SCIFFTX.all = 0xE022; // Interrupt generated when FIFO level is below 2

SciaRegs.SCIFFCT.all = 0x00;

SciaRegs.SCICTL1.all = 0x0022; // Bring SCI out of reset

SciaRegs.SCIFFTX.bit.TXFIFOXRESET = 1;

And the interrupt routine is as follows. SCIChars is the variable where I hold the data I want to transmit, and is declared globally.

interrupt void sciaTxFifoIsr(void) {

int i = 0;

int messageLength = strlen(SCIChars);

char tdx;

while (SciaRegs.SCIFFTX.bit.TXFFST != 0) {}

for (i = 0; i < 2 && SCICounter < messageLength; i++) {

tdx = SCIChars[SCICounter++];

SciaRegs.SCITXBUF = tdx;

}

SciaRegs.SCIFFTX.bit.TXFFINTCLR = 1; // clear interrupt flag

PieCtrlRegs.PIEACK.all |= 0x100; // Issue PIE ACK

}

The interrupt triggers correctly, but I cannot see data coming out from the line. Is there something that I miss? I've set up the TMS320F28035's GPIO 29 as follows:

GpioCtrlRegs.GPAMUX2.bit.GPIO29 = 1; // 0=GPIO,  1=SCITXD-A,  2=I2CSCL-A,  3=TZ3

GpioCtrlRegs.GPADIR.bit.GPIO29 = 1; // 1=OUTput,  0=INput 

GpioCtrlRegs.GPAPUD.bit.GPIO29 = 0;

Thanks