Add getDataRate, add DISABLED to data rate enum

RF24.h

@@ -14,7 +14,7 @@
 
 typedef enum { RF24_PA_MIN = 0,RF24_PA_LOW, RF24_PA_HIGH, RF24_PA_MAX, RF24_PA_ERROR } rf24_pa_dbm_e ;
 typedef enum { RF24_1MBPS = 0, RF24_2MBPS, RF24_250KBPS } rf24_datarate_e;
-typedef enum { RF24_CRC_8 = 0, RF24_CRC_16 } rf24_crclength_e;
+typedef enum { RF24_CRC_DISABLED = 0, RF24_CRC_8, RF24_CRC_16 } rf24_crclength_e;
 
 /**
  * Driver for nRF24L01(+) 2.4GHz Wireless Transceiver
@@ -481,6 +481,13 @@ public:
    */
   void setCRCLength(rf24_crclength_e length);
 
+  /**
+   * Get the CRC length
+   *
+   * @return RF24_DISABLED if disabled or RF24_CRC_8 for 8-bit or RF24_CRC_16 for 16-bit
+   */
+  rf24_crclength_e getCRCLength(void);
+
   /**
    * Disable CRC validation
    *