[SOLVED] Serial Port I receive But can't send

#include <plib.h>				

#if defined (__32MX360F512L__) || (__32MX460F512L__) || (__32MX795F512L__) || (__32MX430F064L__) || (__32MX450F256L__) || (__32MX470F512L__)
// Configuration Bit settings
// SYSCLK = 80 MHz (8MHz Crystal / FPLLIDIV * FPLLMUL / FPLLODIV)
// PBCLK = 80 MHz (SYSCLK / FPBDIV)
// Primary Osc w/PLL (XT+,HS+,EC+PLL)
// WDT OFF
// Other options are don't care
#pragma config FPLLMUL = MUL_20, FPLLIDIV = DIV_2, FPLLODIV = DIV_1, FWDTEN = OFF
#pragma config POSCMOD = HS, FNOSC = PRIPLL, FPBDIV = DIV_1
#define SYS_FREQ (80000000L)
#pragma config ICESEL = ICS_PGx2

#elif defined (__32MX220F032D__) || (__32MX250F128D__)
// Configuration Bit settings
// SYSCLK = 48 MHz (8MHz Crystal / FPLLIDIV * FPLLMUL / FPLLODIV)
// PBCLK = 48 MHz (SYSCLK / FPBDIV)
// Primary Osc w/PLL (XT+,HS+,EC+PLL)
// WDT OFF
// Other options are don't care
#pragma config FPLLMUL = MUL_24, FPLLIDIV = DIV_2, FPLLODIV = DIV_2, FWDTEN = OFF
#pragma config POSCMOD = HS, FNOSC = PRIPLL, FPBDIV = DIV_1
#define SYS_FREQ (48000000L)
#endif

#define	GetPeripheralClock()		(SYS_FREQ/(1 << OSCCONbits.PBDIV))
#define	GetInstructionClock()		(SYS_FREQ)

#if defined (__32MX430F064L__) || (__32MX450F256L__) || (__32MX460F512L__)
#define UART_MODULE_ID UART1 // PIM is connected to Explorer through UART1 module
#else
#define UART_MODULE_ID UART2 // PIM is connected to Explorer through UART2 module
#endif

#define DESIRED_BAUDRATE (9600) //The desired BaudRate


void WriteString(const char *string);
char myChar;

int main(void)
{

    #if defined (__32MX220F032D__) || defined (__32MX250F128D__)
    PPSInput(2,U2RX,RPB5); // Assign RPB5 as input pin for U2RX
    PPSOutput(4,RPB0,U2TX); // Set RPB0 pin as output for U2TX
    #elif defined (__32MX430F064L__) || (__32MX450F256L__) || (__32MX470F512L__)
    PPSInput(2,U1RX,RPF4); // Assign RPF4 as input pin for U1RX
    PPSOutput(2,RPF5,U1TX); // Set RPF5 pin as output for U1TX
    #endif

    // Configure the device for maximum performance but do not change the PBDIV
    // Given the options, this function will change the flash wait states, RAM
    // wait state and enable prefetch cache but will not change the PBDIV.
    // The PBDIV value is already set via the pragma FPBDIV option above.
    SYSTEMConfig(SYS_FREQ, SYS_CFG_WAIT_STATES | SYS_CFG_PCACHE);

    // Explorer-16 LEDs are on lower 8-bits of PORTA and to use all LEDs, JTAG port must be disabled.
    mJTAGPortEnable(DEBUG_JTAGPORT_OFF);

    PORTClearBits(IOPORT_B,BIT_10|BIT_11|BIT_12|BIT_13 );
    PORTSetPinsDigitalOut (IOPORT_B, BIT_10|BIT_11|BIT_12|BIT_13);
    //mPORTBClearBits(BIT_10); 		// Turn off RA7 on startup.
    //mPORTASetPinsDigitalOut(BIT_10);	// Make RA7 as output.

    // Configure UART module, set buad rate, turn on UART, etc.
    UARTConfigure(UART_MODULE_ID, UART_ENABLE_PINS_TX_RX_ONLY);
    UARTSetFifoMode(UART_MODULE_ID, UART_INTERRUPT_ON_TX_NOT_FULL | UART_INTERRUPT_ON_RX_NOT_EMPTY);
    UARTSetLineControl(UART_MODULE_ID, UART_DATA_SIZE_8_BITS | UART_PARITY_NONE | UART_STOP_BITS_1);
    UARTSetDataRate(UART_MODULE_ID, GetPeripheralClock(), DESIRED_BAUDRATE);
    UARTEnable(UART_MODULE_ID, UART_ENABLE_FLAGS(UART_PERIPHERAL | UART_RX | UART_TX));

    // Configure UART RX Interrupt
    INTEnable(INT_SOURCE_UART_RX(UART_MODULE_ID), INT_ENABLED);
    INTSetVectorPriority(INT_VECTOR_UART(UART_MODULE_ID), INT_PRIORITY_LEVEL_2);
    INTSetVectorSubPriority(INT_VECTOR_UART(UART_MODULE_ID), INT_SUB_PRIORITY_LEVEL_0);

    // Enable multi-vector interrupts
    INTConfigureSystem(INT_SYSTEM_CONFIG_MULT_VECTOR);
    INTEnableInterrupts();

    WriteString("***version 1.0***\r\n");

    // Let interrupt handler do the work
    while (1);
}
// Helper functions
void WriteString(const char *string)
{
    while(*string != '\0')
    {
        while(!UARTTransmitterIsReady(UART_MODULE_ID))
            ;

        UARTSendDataByte(UART_MODULE_ID, *string);

        string++;

        while(!UARTTransmissionHasCompleted(UART_MODULE_ID))
            ;
    }
}
void PutCharacter(const char character)
{
        while(!UARTTransmitterIsReady(UART_MODULE_ID))
            ;

        UARTSendDataByte(UART_MODULE_ID, character);


        while(!UARTTransmissionHasCompleted(UART_MODULE_ID))
            ;
}

// UART 1 interrupt handler, set at priority level 2
#if defined (__32MX430F064L__) || (__32MX450F256L__) || (__32MX460F512L__)
void __ISR(_UART_1_VECTOR, ipl2) IntUart1Handler(void)
{ 
	// Is this an RX interrupt?
	if(INTGetFlag(INT_SOURCE_UART_RX(UART_MODULE_ID)))
	{
            // Clear the RX interrupt Flag
	    INTClearFlag(INT_SOURCE_UART_RX(UART_MODULE_ID));

     
           PutCharacter(UARTGetDataByte(UART_MODULE_ID));
           myChar = UARTGetDataByte(UART_MODULE_ID);
 
           if(myChar=='a'){
               PORTToggleBits(IOPORT_B , BIT_10|BIT_11|BIT_12|BIT_13);
               WriteString(myChar);
           }
            //mPORTBToggleBits(BIT_10);
	}

	// We don't care about TX interrupt
	if (INTGetFlag(INT_SOURCE_UART_TX(UART_MODULE_ID)))
	{
            INTClearFlag(INT_SOURCE_UART_TX(UART_MODULE_ID));
	}
}

#else

// UART 2 interrupt handler, set at priority level 2
void __ISR(_UART2_VECTOR, ipl2) IntUart2Handler(void)
{
	// Is this an RX interrupt?
	if(INTGetFlag(INT_SOURCE_UART_RX(UART_MODULE_ID)))
	{
            // Clear the RX interrupt Flag
	    INTClearFlag(INT_SOURCE_UART_RX(UART_MODULE_ID));

            // Echo what we just received.
            PutCharacter(UARTGetDataByte(UART_MODULE_ID));

            // Toggle LED to indicate UART activity
            mPORTBToggleBits(BIT_10);
	}

	// We don't care about TX interrupt
	if ( INTGetFlag(INT_SOURCE_UART_TX(UART_MODULE_ID)) )
	{
            INTClearFlag(INT_SOURCE_UART_TX(UART_MODULE_ID));
	}
}
#endif

void WriteString(const char *string)
{
    while(*string != '\0')
    {
        while(!UARTTransmitterIsReady(UART_MODULE_ID))
            ;

        UARTSendDataByte(UART_MODULE_ID, *string);

        string++;

        while(!UARTTransmissionHasCompleted(UART_MODULE_ID))
            ;
    }
}