RTOS/LAUNCHXL-CC1310: UART_read Problem...

Tool/software: TI-RTOS

Hi , i have a problem with 

uart_read();

using the uartecho.c example, i can´t read any byte from the port rx...

this is my code:

char input;
char echoPrompt[] = "Echoing characters:\r\n";
UART_Handle uart;
UART_Params uartParams;
UART_init();

UART_Params_init(&uartParams);
uartParams.writeDataMode = UART_DATA_BINARY;
uartParams.readDataMode = UART_DATA_BINARY;
uartParams.writeMode = UART_MODE_CALLBACK;
uartParams.readMode = UART_MODE_CALLBACK;
uartParams.readReturnMode = UART_RETURN_FULL;
uartParams.readEcho = UART_ECHO_OFF;
uartParams.baudRate = 115200;

uart = UART_open(Board_UART0, &uartParams);

if (uart == NULL) {
/* UART_open() failed */
while (1);
}

UART_write(uart, echoPrompt, sizeof(echoPrompt));
UART_read(uart, &input, sizeof(echoPrompt));