feat: Arduino Uno R4 support

Author: zfields

Boards.h

@@ -141,6 +141,13 @@ writePort(port, value, bitmask):  Write an 8 bit port.
 #define digitalPinHasPWM(p)     IS_PIN_DIGITAL(p)
 #endif
 
+#undef IS_PIN_INTERRUPT
+#if defined(digitalPinToInterrupt) && defined(NOT_AN_INTERRUPT)
+#define IS_PIN_INTERRUPT(p)     (digitalPinToInterrupt(p) > NOT_AN_INTERRUPT)
+#else
+#define IS_PIN_INTERRUPT(p)     (0)
+#endif
+
 // Arduino Duemilanove, Diecimila, and NG
 #if defined(__AVR_ATmega168__) || defined(__AVR_ATmega328P__) || defined(__AVR_ATmega328__)
 #if defined(NUM_ANALOG_INPUTS) && NUM_ANALOG_INPUTS == 6
@@ -447,6 +454,30 @@ writePort(port, value, bitmask):  Write an 8 bit port.
 #define PIN_TO_PWM(p)           PIN_TO_DIGITAL(p)
 #define PIN_TO_SERVO(p)         (p) // deprecated since v2.4
 
+// Arduino UNO R4 Minima and Wifi
+// The pinout is the same as for the classical UNO R3
+#elif defined(ARDUINO_UNOR4_MINIMA) || defined(ARDUINO_UNOR4_WIFI)
+#if defined(NUM_ANALOG_INPUTS) && NUM_ANALOG_INPUTS == 6
+#define TOTAL_ANALOG_PINS       6
+#define TOTAL_PINS              20 // 14 digital + 6 analog
+#else
+#define TOTAL_ANALOG_PINS       8
+#define TOTAL_PINS              22 // 14 digital + 8 analog
+#endif
+// These have conflicting(?) definitions in the core for this CPU
+#undef IS_PIN_PWM
+#undef IS_PIN_ANALOG
+#define VERSION_BLINK_PIN       13
+#define IS_PIN_DIGITAL(p)       ((p) >= 2 && (p) <= 19)
+#define IS_PIN_ANALOG(p)        ((p) >= 14 && (p) < 14 + TOTAL_ANALOG_PINS)
+#define IS_PIN_PWM(p)           digitalPinHasPWM(p)
+#define IS_PIN_SERVO(p)         (IS_PIN_DIGITAL(p) && (p) - 2 < MAX_SERVOS)
+#define IS_PIN_I2C(p)           ((p) == 18 || (p) == 19)
+#define IS_PIN_SPI(p)           ((p) == SS || (p) == MOSI || (p) == MISO || (p) == SCK)
+#define PIN_TO_DIGITAL(p)       (p)
+#define PIN_TO_ANALOG(p)        ((p) - 14)
+#define PIN_TO_PWM(p)           PIN_TO_DIGITAL(p)
+#define PIN_TO_SERVO(p)         ((p) - 2)
 
 // Teensy 1.0
 #elif defined(__AVR_AT90USB162__)