CC2540 RSSI value extract

Hi

I using IAR workbench for development of cc2540 ble . I want display rssi value cc2540KEYFOB on terminal window .

This is sample code

static void simpleBLECentralRssiCB( uint16 connHandle, int8 rssi )
{
  int8 x;
  x = rssi;

}

I used printf(x) for display  "x" , but it not display x value on terminal window.
 There is any other function or alternative option.