Error connecting to the target: Could not find device (or device not supported)

Try these troubleshooting steps without Code Composer Studio and report your results.

1. Test the communication between your computer and the programming tool.  What are your results?
2. Erase the flash on your MSP430.  What are your results?
3. Load a program to the MSP430 that blinks an LED.  What are your results?

MSP 430FG439-debugging problem

I have checked these things.

1. Yes, the computer communicates with the programming tool. 

2. I could not erase the code. The programming software displays a 'failed' message few days back a simple rs-232 echo code was run...it's is still running( a small issue in this, we set 115200 baudrate in the code, but it's it echoes(outputs) only if we set the system's baud rate less than or equal to 600. I guess this is 'coz I didn't set UCOS16 to 1 as my internal clock speed was set to run at 8 Mz)

3.And the last one, I'm not able to load any code now as it displays 'failed' message

And fyi, I have never clicked on that update when it asks for. 

I've replaced the controller with another one. It worked for some 7 times. And after that again the same situation. It is not being detected by the FET. But the code is running as the echo code which was loaded  still produces an output but at lower baud rate set in the computer. 

It's possible that a combination of your target's power supply and the FET and its GND connection to the PC and the PCs power supply damage the JTAG port pins. Normally, this shouldn't happen, but in some setups, e.g. if the PC and the target power supply sourced by different AC phases or a different AC powerline, this is possible (a so-called GND loop).

Try to check the JTAG pins of the defective MSP against GND or VCC (outside the circuit) with a diode tester. Likely you'll see that one of the pins is shorted to GND (less likely to VCC) after its clamp diode melted down.

I've replaced the micro controller twice on my board. Now it's getting programmed. No problems observed even programming it several times. But when I programmed it with an rs-232 echo code, it works at  lower baud rates (9600 set in the code, but works when computer's baud rate is set to 600 or below). 

#include "msp430f247.h"

int main(void)
{
WDTCTL = WDTPW + WDTHOLD; // Stop WDT
_DINT(); //Disable Interrupt
_NOP();

if (CALBC1_8MHZ ==0xFF || CALDCO_8MHZ == 0xFF) // If calibration constants erased, do not load, trap CPU!!
{
while(1);
}
// Set system DCO to 8MHz //

BCSCTL1 = CALBC1_8MHZ;
DCOCTL = CALDCO_8MHZ;

_EINT();

P3SEL = 0x0C0; // P3.6,7 = USCI_A1 TXD/RXD
//P3DIR = 0xFF; // All P3.x outputs
// P3OUT = 0; // All P3.x reset


UCA1CTL1 |= UCSWRST;
UCA1CTL1 |= UCSSEL_2; // CLK = SMCLK
UCA1BR0 = 0x13; // 8MHz/9600 = 833.33
UCA1BR1 = 0; //
//UCA1MCTL = UCBRS2+UCBRS1;
UCA1MCTL = 0x01;
UCA1CTL1 &= ~UCSWRST; // **Initialize USCI state machine**
UC1IE |= UCA1RXIE; // Enable USCI_A1 RX interrupt
UC1IE |= UCA1TXIE;

}

// Echo back RXed character, confirm TX buffer is ready first

#pragma vector=USCIAB1RX_VECTOR
__interrupt void USCIAB1RX_ISR(void)
{
while (!(UC1IFG&UCA1TXIFG)); // USCI_A1 TX buffer ready?
UCA1TXBUF = UCA1RXBUF; // TX -> RXed character
}

I've operated it with lower clock speeds  and also used UCOS16 bit at higher clock speeds which is missing in the previous post(couldn't delete or edit that post)