Add default pins for Arduino MKR CAN shield

when using Arduino SAMD that is not the Arduino Zero

Author: sandeepmistry

README.md

@@ -7,6 +7,7 @@ An Arduino library for sending and receiving data using CAN bus.
 ## Compatible Hardware
 
 * [Microchip MCP2515](http://www.microchip.com/wwwproducts/en/en010406) based boards/shields
+  * [Arduino MKR CAN shield](https://store.arduino.cc/arduino-mkr-can-shield)
 * [Espressif ESP32](http://espressif.com/en/products/hardware/esp32/overview)'s built-in [SJA1000](https://www.nxp.com/products/analog/interfaces/in-vehicle-network/can-transceiver-and-controllers/stand-alone-can-controller:SJA1000T) compatible CAN controller with an external 3.3V CAN transceiver
 
 ### Microchip MCP2515 wiring

src/MCP2515.h

@@ -10,9 +10,16 @@
 
 #include "CANController.h"
 
+#if defined(ARDUINO_ARCH_SAMD) && defined(USB_VID) && (USB_VID == 0x2341) && !defined(ARDUINO_SAMD_ZERO)
+// Arduino MKR board: MKR CAN shield CS is pin 3, INT is pin 7
+#define MCP2515_DEFAULT_CLOCK_FREQUENCY 16e6
+#define MCP2515_DEFAULT_CS_PIN          3
+#define MCP2515_DEFAULT_INT_PIN         7
+#else
 #define MCP2515_DEFAULT_CLOCK_FREQUENCY 16e6
 #define MCP2515_DEFAULT_CS_PIN          10
 #define MCP2515_DEFAULT_INT_PIN         2
+#endif
 
 class MCP2515Class : public CANControllerClass {