SemaphoreP_Handle callbackSem = NULL;
/*
 *  ======== UART callback test ========
 *
 *  The test function tests the read/write in callback mode
 */
static bool UART_test_callback(bool dmaMode)
{
    char              rx_buf[32];
	const char        message_to_send_by_uart[EXPECTED_MSG_LENGTH] = "message to send by uart!\n";
    bool              ret = false;

    /* Create call back semaphore */
	SemaphoreP_Params semParams;
    UART_osalSemParamsInit(&semParams);
    semParams.mode = SemaphoreP_Mode_BINARY;
    callbackSem = UART_osalCreateBlockingLock(0, &semParams);

    /* Test read/write API's in callback mode */

    /* UART SoC init configuration */
    /* Get the default UART init configurations */
	UART_HwAttrs uart_cfg;
    UART_socGetInitCfg(uartTestInstance, &uart_cfg);
    uart_cfg.edmaHandle = NULL;
    uart_cfg.dmaMode    = FALSE;
    uart_cfg.loopback   = FALSE;

    /* Set the DMA enabled UART init configurations */
    UART_socSetInitCfg(uartTestInstance, &uart_cfg);

    /* Set callback mode for both read and write */
	UART_Params       uartParams;
    UART_Params_init(&uartParams);
    uartParams.readCallback = UART_callback;
    uartParams.readMode = UART_MODE_CALLBACK;
    uartParams.parityType = uartParity;

    UART_Handle uart = UART_open(uartTestInstance, &uartParams);
    if (uart == NULL)
    {
        goto Err;
    }

    memset(rx_buf, 0, 32);

    if (UART_read(uart, (void *)&rx_buf[0], 32) == UART_ERROR)
    {
        goto Err;
    }
	
    if (UART_write(uart, (void *)&message_to_send_by_uart[0], sizeof(message_to_send_by_uart)) == UART_ERROR)
    {
        goto Err;
    }
	
    if (UART_osalPendLock(callbackSem, uartParams.writeTimeout) != SemaphoreP_OK)-> stop here unless I input on serial port. UART_write doesn't trigger callback function
    {
        goto Err;
    }

	ret = true;
Err:
    if (uart)
    {
        UART_close(uart);
    }
    if (callbackSem)
    {
    	UART_osalDeleteBlockingLock(callbackSem);
    	callbackSem = NULL;
    }
    return (ret);
}