例程问题 WBJ

您好：
WBJ，这是我对你的代码进行的修改，红色部分：

static void rfEasyLinkRxTxFnx(UArg arg0, UArg arg1)
{
#ifndef RFEASYLINKRX_ASYNC
    EasyLink_RxPacket rxPacket = {0};
#endif
    //add by barbara -- begin
        /* Create a semaphore for Async*/
    Semaphore_Params paramsTx;
    Error_Block ebTx;

    /* Init params */
    Semaphore_Params_init(&paramsTx);
    Error_init(&ebTx);

    /* Create semaphore instance */
    txDoneSem = Semaphore_create(0, &paramsTx, &ebTx);
    //add by barbara -- end
    
    EasyLink_init(EasyLink_Phy_50kbps2gfsk);
    EasyLink_setFrequency(868000000);

#ifdef RFEASYLINKRX_ADDR_FILTER
    uint8_t addrFilter = 0xac;
    EasyLink_enableRxAddrFilter(&addrFilter, 1, 1);
#endif //RFEASYLINKRX_ADDR_FILTER
    
    //add by barbara -- begin
        /* Setup callback for button pins */
    if (PIN_registerIntCb(buttonPinHandle, &buttonCallbackFunction) != 0) {
        System_abort("Error registering button callback function");
    }
    

    //add by barbara -- end

    while(1) {
      if(!TxSendFlag)
      {
          //System_printf("TxSendFlag is FAlSE, EasyLink_receive will be call\n");
        rxPacket.absTime = 0;
        EasyLink_Status result = EasyLink_receive(&rxPacket);

        if (result == EasyLink_Status_Success)
        {
            len = rxPacket.len;
            memcpy(payload, rxPacket.payload, len);
            
            Uart_PostEvent(UART_EVENT_PRINT);
            if(payload[3]==0x05)
            {
              SwithtoTx("nihao", 5);
            }
            /* Toggle LED2 to indicate RX */
            PIN_setOutputValue(pinHandle, Board_LED2,!PIN_getOutputValue(Board_LED2));
        }
        else
        {
            /* Toggle LED1 and LED2 to indicate error */
            PIN_setOutputValue(pinHandle, Board_LED1,!PIN_getOutputValue(Board_LED1));
            PIN_setOutputValue(pinHandle, Board_LED2,!PIN_getOutputValue(Board_LED2));
        }
        //System_printf("TxSendFlag is FAlSE, EasyLink_receive call returned\n");
      }
      else
      {
           PIN_setOutputValue(pinHandle, Board_LED1,!PIN_getOutputValue(Board_LED1));
           PIN_setOutputValue(pinHandle, Board_LED2,!PIN_getOutputValue(Board_LED2));
           Semaphore_pend(txDoneSem, BIOS_WAIT_FOREVER);   //if in TX mode pend event;
      }
    }
}

能正常接收代码，接收到0x05后，调用Switchtotx功能函数，但是发送不成功，不明白原因，这个和串口调用应该没什么区别吧，为什么稍作改动就不能正常运行呢