diff --git a/.gitignore b/.gitignore
index 7e69f457..6daf2ebc 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,5 @@
 *.bak
 *.zip
 *.rar
-build/
\ No newline at end of file
+build/
+venv/
diff --git a/.travis.yml b/.travis.yml
index 1b1f1378..1f5eb687 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -90,7 +90,7 @@ script:
     - if [[ -z "$SKIP_UNO" ]]; then UNO="--board=uno"; fi
     - if [[ -z "$SKIP_TEENSY35" ]]; then TEENSY35="--board=teensy35"; fi
     - if [[ -z "$SKIP_TEENSY36" ]]; then TEENSY36="--board=teensy36"; fi
-    - platformio ci --lib="." $UNO --board=genuino101 --board=teensy30 --board=teensy31 $TEENSY35 $TEENSY36 --board=teensylc --board=esp12e --board=nodemcu --board=esp32dev
+    - platformio ci --lib="." $UNO --board=genuino101 --board=teensy30 --board=teensy31 $TEENSY35 $TEENSY36 --board=teensylc --board=teensy40 --board=teensy41 --board=esp12e --board=nodemcu --board=esp32dev
     - platformio ci --lib="." --board=due --project-option="build_flags=-Wno-misleading-indentation" # Workaround https://travis-ci.org/felis/USB_Host_Shield_2.0/jobs/569237654 and https://github.com/arduino/ArduinoCore-sam/issues/69
 
 before_deploy:
diff --git a/README.md b/README.md
index cac71f6e..40b51d91 100644
--- a/README.md
+++ b/README.md
@@ -109,7 +109,7 @@ Currently the following boards are supported by the library:
 * Arduino Due, Intel Galileo, Intel Galileo 2, and Intel Edison
     * Note that the Intel Galileo uses pin 2 and 3 as INT and SS pin respectively by default, so some modifications to the shield are needed. See the "Interface modifications" section in the [hardware manual](https://chome.nerpa.tech/usb-host-shield-hardware-manual) for more information.
     * Note native USB host is not supported on any of these platforms. You will have to use the shield for now.
-* Teensy (Teensy++ 1.0, Teensy 2.0, Teensy++ 2.0, Teensy 3.x, and Teensy LC)
+* Teensy (Teensy++ 1.0, Teensy 2.0, Teensy++ 2.0, Teensy 3.x, Teensy LC and Teensy 4.x)
     * Note if you are using the Teensy 3.x you should download this SPI library as well: <https://github.com/xxxajk/spi4teensy3>. You should then add ```#include <spi4teensy3.h>``` to your .ino file.
 * Balanduino
 * Sanguino
diff --git a/avrpins.h b/avrpins.h
index d5c7c4aa..8598d93d 100644
--- a/avrpins.h
+++ b/avrpins.h
@@ -814,6 +814,7 @@ public:
 #define pgm_read_pointer(p) pgm_read_dword(p)
 
 #if defined(CORE_TEENSY) && (defined(__MK20DX128__) || defined(__MK20DX256__) || defined(__MK64FX512__) || defined(__MK66FX1M0__))
+// Teensy 3.x
 
 #include "core_pins.h"
 #include "avr_emulation.h"
@@ -913,6 +914,7 @@ MAKE_PIN(P63, CORE_PIN63_PORTREG, CORE_PIN63_BIT, CORE_PIN63_CONFIG);
 #undef MAKE_PIN
 
 #elif defined(CORE_TEENSY) && (defined(__MKL26Z64__))
+// Teensy-LC
 
 // we could get lower level by making these macros work properly.
 // for now just use the semi optimised version, it costs a lookup in the pin pgm table per op
@@ -976,6 +978,91 @@ MAKE_PIN(P26, CORE_PIN26_PORTREG, 26, CORE_PIN26_CONFIG);
 
 #undef MAKE_PIN
 
+#elif defined(__IMXRT1062__) && (defined(ARDUINO_TEENSY40) || defined(ARDUINO_TEENSY41))
+// Teensy 4.x
+
+#include "core_pins.h"
+
+#define MAKE_PIN(className, pin) \
+class className { \
+public: \
+  static void Set() { \
+    digitalWriteFast(pin, HIGH);\
+  } \
+  static void Clear() { \
+    digitalWriteFast(pin, LOW); \
+  } \
+  static void SetDirRead() { \
+    pinMode(pin, INPUT); \
+  } \
+  static void SetDirWrite() { \
+    pinMode(pin, OUTPUT); \
+  } \
+  static uint8_t IsSet() { \
+    return digitalReadFast(pin); \
+  } \
+};
+
+MAKE_PIN(P0, 0);
+MAKE_PIN(P1, 1);
+MAKE_PIN(P2, 2);
+MAKE_PIN(P3, 3);
+MAKE_PIN(P4, 4);
+MAKE_PIN(P5, 5);
+MAKE_PIN(P6, 6);
+MAKE_PIN(P7, 7);
+MAKE_PIN(P8, 8);
+MAKE_PIN(P9, 9);
+MAKE_PIN(P10, 10);
+MAKE_PIN(P11, 11);
+MAKE_PIN(P12, 12);
+MAKE_PIN(P13, 13);
+MAKE_PIN(P14, 14);
+MAKE_PIN(P15, 15);
+MAKE_PIN(P16, 16);
+MAKE_PIN(P17, 17);
+MAKE_PIN(P18, 18);
+MAKE_PIN(P19, 19);
+MAKE_PIN(P20, 20);
+MAKE_PIN(P21, 21);
+MAKE_PIN(P22, 22);
+MAKE_PIN(P23, 23);
+MAKE_PIN(P24, 24);
+MAKE_PIN(P25, 25);
+MAKE_PIN(P26, 26);
+MAKE_PIN(P27, 27);
+MAKE_PIN(P28, 28);
+MAKE_PIN(P29, 29);
+MAKE_PIN(P30, 30);
+MAKE_PIN(P31, 31);
+MAKE_PIN(P32, 35);
+MAKE_PIN(P33, 33);
+MAKE_PIN(P34, 34);
+MAKE_PIN(P35, 35);
+MAKE_PIN(P36, 36);
+MAKE_PIN(P37, 37);
+MAKE_PIN(P38, 38);
+MAKE_PIN(P39, 39);
+#ifdef ARDUINO_TEENSY41
+MAKE_PIN(P40, 40);
+MAKE_PIN(P41, 41);
+MAKE_PIN(P42, 42);
+MAKE_PIN(P43, 43);
+MAKE_PIN(P44, 44);
+MAKE_PIN(P45, 45);
+MAKE_PIN(P46, 46);
+MAKE_PIN(P47, 47);
+MAKE_PIN(P48, 48);
+MAKE_PIN(P49, 49);
+MAKE_PIN(P50, 50);
+MAKE_PIN(P51, 51);
+MAKE_PIN(P52, 52);
+MAKE_PIN(P53, 53);
+MAKE_PIN(P54, 54);
+#endif
+
+#undef MAKE_PIN
+
 #elif defined(ARDUINO_SAM_DUE) && defined(__SAM3X8E__)
 
 // SetDirRead: