c# interface to control msp430 help

Development Boards MicroMod
1

Hi! I’m new with msp430f169 and I want to write a simple application to blink a led at various speed. In windows part, there is a button to start blinking and a trackbar to change blinking speed. Variables (like blinking speed) are converted into strings then sent to serial port. In msp430 part, I want to take the values from serial port and compare them, do the operation; but the program doesn’t work? Can you help me? What is wrong with this code?

#include <msp430x16x.h>
void blinker (unsigned int);  
  unsigned int a=100;
  char m[1];

void main(void)
{
  WDTCTL = WDTPW + WDTHOLD;       // Stop WDT
  P3SEL |= 0xC0; // P3.6,7 = USART1 option select
  ME2 |= UTXE1 + URXE1; // Enable USART1 TXD/RXD
  //ME1 |= UTXE0 + URXE0; 

  UCTL1 |= CHAR;     // 8-bit character
  UTCTL1 |= SSEL0;   // UCLK = ACLK
  UBR01 = 0x0D;      // 32k/2400 - 13.65
  UBR11 = 0x00;                         
  UMCTL1 = 0x6B;     // Modulation
  UCTL1 &= ~SWRST;   // Initialize USART state machine
  IE2 |= URXIE1;     // Enable USART1 RX interrupt
  //BTCTL = BTDIV + BT_fCLK2_DIV4;
  
// Mainloop
  for (;;)                              
  {
  _BIS_SR(GIE);   // Enter LPM3 w/interrupt
  blinker (a);
	 }
}

//#if 1
// UART1 RX ISR will for exit from LPM3 in Mainloop
#pragma vector= USART1RX_VECTOR
__interrupt void usart1_rx (void)
{
  //_BIC_SR_IRQ(LPM3_bits);// Clear LPM3 bits from 0(SR)
  m[0]=RXBUF1;
	
  switch(m[0]){
   case 'A':
	blinker(a);
   case '1':
	a=100;
   case '2':
	a=500;
   case '3':
	a=1000;
   case '4':
	a=5000;
   case '5':
	a=10000;
 	}
}

//#endif



void blinker(unsigned int m)
{
   while (m>0);{
	P5OUT ^= 0x02;
	m--;
}}