Stabilize onReceive(...) callback handling

Author: sandeepmistry

src/CAN.cpp

@@ -386,9 +386,13 @@ void CANClass::onReceive(void(*callback)(int))
   pinMode(_irq, INPUT);
 
   if (callback) {
-    attachInterrupt(digitalPinToInterrupt(_irq), CANClass::onIntLow, LOW);
+    SPI.usingInterrupt(digitalPinToInterrupt(_irq));
+    attachInterrupt(digitalPinToInterrupt(_irq), CANClass::onInterrupt, LOW);
   } else {
     detachInterrupt(digitalPinToInterrupt(_irq));
+#ifdef SPI_HAS_NOTUSINGINTERRUPT
+    SPI.notUsingInterrupt(digitalPinToInterrupt(_irq));
+#endif
   }
 }
 
@@ -464,9 +468,13 @@ void CANClass::reset()
   delayMicroseconds(10);
 }
 
-void CANClass::handleIntLow()
+void CANClass::handleInterrupt()
 {
-  while (parsePacket() != 0) {
+  if (readRegister(REG_CANINTF) == 0) {
+    return;
+  }
+
+  while (parsePacket()) {
     _onReceive(available());
   }
 }
@@ -515,9 +523,9 @@ void CANClass::writeRegister(uint8_t address, uint8_t value)
   digitalWrite(_ss, HIGH);
 }
 
-void CANClass::onIntLow()
+void CANClass::onInterrupt()
 {
-  CAN.handleIntLow();
+  CAN.handleInterrupt();
 }
 
 CANClass CAN;

src/CAN.h

@@ -53,13 +53,13 @@ class CANClass : public Stream {
 private:
   void reset();
 
-  void handleIntLow();
+  void handleInterrupt();
 
   uint8_t readRegister(uint8_t address);
   void modifyRegister(uint8_t address, uint8_t mask, uint8_t value);
   void writeRegister(uint8_t address, uint8_t value);
 
-  static void onIntLow();
+  static void onInterrupt();
 
 private:
   SPISettings _spiSettings;