diff --git a/RFM69.cpp b/RFM69.cpp
index 8e18045..b3bc30d 100644
--- a/RFM69.cpp
+++ b/RFM69.cpp
@@ -154,11 +154,6 @@ bool RFM69::initialize(uint8_t freqBand, uint16_t nodeID, uint8_t networkID)
   return true;
 }
 
-void RFM69::setIsrCallback(void (*callback)())
-{
-  _isrCallback = callback;
-}
-
 // return the frequency (in Hz)
 uint32_t RFM69::getFrequency()
 {
@@ -234,6 +229,12 @@ void RFM69::setNetwork(uint8_t networkID)
   writeReg(REG_SYNCVALUE2, networkID);
 }
 
+//set user's ISR callback
+void RFM69::setIsrCallback(void (*callback)())
+{
+  _isrCallback = callback;
+}
+
 // Control transmitter output power (this is NOT a dBm value!)
 // the power configurations are explained in the SX1231H datasheet (Table 10 on p21; RegPaLevel p66): http://www.semtech.com/images/datasheet/sx1231h.pdf
 // valid powerLevel parameter values are 0-31 and result in a directly proportional effect on the output/transmission power
diff --git a/RFM69.h b/RFM69.h
index 2d511e2..c5f029c 100644
--- a/RFM69.h
+++ b/RFM69.h
@@ -201,9 +201,9 @@ class RFM69 {
     RFM69(uint8_t slaveSelectPin=RF69_SPI_CS, uint8_t interruptPin=RF69_IRQ_PIN, bool isRFM69HW_HCW=false, SPIClass *spi=nullptr);
 
     bool initialize(uint8_t freqBand, uint16_t ID, uint8_t networkID=1);
-    void setIsrCallback(void (*callback)());
     void setAddress(uint16_t addr);
     void setNetwork(uint8_t networkID);
+    void setIsrCallback(void (*callback)());
     virtual bool canSend();
     virtual void send(uint16_t toAddress, const void* buffer, uint8_t bufferSize, bool requestACK=false);
     virtual bool sendWithRetry(uint16_t toAddress, const void* buffer, uint8_t bufferSize, uint8_t retries=2, uint8_t retryWaitTime=RFM69_ACK_TIMEOUT);
@@ -249,7 +249,6 @@ class RFM69 {
     virtual void interruptHook(uint8_t CTLbyte __attribute__((unused))) {};
     static volatile bool _haveData;
     static RFM69 *_instance;
-    void (*_isrCallback)() = nullptr;
     virtual void sendFrame(uint16_t toAddress, const void* buffer, uint8_t size, bool requestACK=false, bool sendACK=false);
 
     // for ListenMode sleep/timer
@@ -263,6 +262,7 @@ class RFM69 {
     uint8_t _powerLevel;
     bool _isRFM69HW;
     SPIClass *_spi;
+    void (*_isrCallback)() = nullptr;
 #if defined (SPCR) && defined (SPSR)
     uint8_t _SPCR;
     uint8_t _SPSR;