diff --git a/ports/atmel-samd/board_busses.c b/ports/atmel-samd/board_busses.c
index 52aa5a366e..02d08133c7 100644
--- a/ports/atmel-samd/board_busses.c
+++ b/ports/atmel-samd/board_busses.c
@@ -26,6 +26,8 @@
 
 #include "shared-bindings/busio/I2C.h"
 #include "shared-bindings/busio/SPI.h"
+#include "shared-bindings/busio/UART.h"
+
 #include "shared-bindings/microcontroller/Pin.h"
 #include "mpconfigboard.h"
 #include "pins.h"
@@ -34,13 +36,10 @@
 
 
 #if !defined(DEFAULT_I2C_BUS_SDA) || !defined(DEFAULT_I2C_BUS_SCL)
-
     STATIC mp_obj_t board_i2c(void) {
-        //board_i2c_obj = NULL;
         mp_raise_NotImplementedError("No default I2C bus");
         return NULL;
     }
-
 #else
     STATIC mp_obj_t i2c_singleton = NULL;
 
@@ -59,7 +58,6 @@
 
     }
 #endif
-
 MP_DEFINE_CONST_FUN_OBJ_0(board_i2c_obj, board_i2c);
 
 #if !defined(DEFAULT_SPI_BUS_SCK) || !defined(DEFAULT_SPI_BUS_MISO) || !defined(DEFAULT_SPI_BUS_MOSI)
@@ -88,3 +86,30 @@ MP_DEFINE_CONST_FUN_OBJ_0(board_i2c_obj, board_i2c);
     }
 #endif
 MP_DEFINE_CONST_FUN_OBJ_0(board_spi_obj, board_spi);
+
+#if !defined(DEFAULT_UART_BUS_RX) || !defined(DEFAULT_UART_BUS_TX)
+    STATIC mp_obj_t board_uart(void) {
+        mp_raise_NotImplementedError("No default UART bus");
+        return NULL;
+    }
+#else
+    STATIC mp_obj_t uart_singleton = NULL;
+
+    STATIC mp_obj_t board_uart(void) {
+        if (uart_singleton == NULL) {
+            busio_uart_obj_t *self = m_new_obj(busio_uart_obj_t);
+            self->base.type = &busio_uart_type;
+
+            assert_pin_free(DEFAULT_UART_BUS_RX);
+            assert_pin_free(DEFAULT_UART_BUS_TX);
+
+            const mcu_pin_obj_t* rx = MP_OBJ_TO_PTR(DEFAULT_UART_BUS_RX);
+            const mcu_pin_obj_t* tx = MP_OBJ_TO_PTR(DEFAULT_UART_BUS_TX);
+
+            common_hal_busio_uart_construct(self, tx, rx, 9600, 8, PARITY_NONE, 1, 1000, 64);
+            uart_singleton = (mp_obj_t)self;
+        }
+        return uart_singleton;
+    }
+#endif
+MP_DEFINE_CONST_FUN_OBJ_0(board_uart_obj, board_uart);
\ No newline at end of file
diff --git a/ports/atmel-samd/board_busses.h b/ports/atmel-samd/board_busses.h
index d0cd5dbf78..a368885a58 100644
--- a/ports/atmel-samd/board_busses.h
+++ b/ports/atmel-samd/board_busses.h
@@ -33,4 +33,7 @@ extern mp_obj_fun_builtin_fixed_t board_i2c_obj;
 void board_spi(void);
 extern mp_obj_fun_builtin_fixed_t board_spi_obj;
 
+void board_uart(void);
+extern mp_obj_fun_builtin_fixed_t board_uart_obj;
+
 #endif  // MICROPY_INCLUDED_ATMEL_SAMD_BOARD_BUSSES_H
diff --git a/ports/atmel-samd/boards/arduino_zero/mpconfigboard.h b/ports/atmel-samd/boards/arduino_zero/mpconfigboard.h
index 0f930767ad..a32f128f52 100644
--- a/ports/atmel-samd/boards/arduino_zero/mpconfigboard.h
+++ b/ports/atmel-samd/boards/arduino_zero/mpconfigboard.h
@@ -21,3 +21,6 @@
 #define DEFAULT_SPI_BUS_SCK (&pin_PB11)
 #define DEFAULT_SPI_BUS_MOSI (&pin_PB10)
 #define DEFAULT_SPI_BUS_MISO (&pin_PA12)
+
+#define DEFAULT_UART_BUS_RX (&pin_PA11)
+#define DEFAULT_UART_BUS_TX (&pin_PA10)
diff --git a/ports/atmel-samd/boards/arduino_zero/pins.c b/ports/atmel-samd/boards/arduino_zero/pins.c
index 8a4fe09017..4fa417b373 100644
--- a/ports/atmel-samd/boards/arduino_zero/pins.c
+++ b/ports/atmel-samd/boards/arduino_zero/pins.c
@@ -34,5 +34,6 @@ STATIC const mp_rom_map_elem_t board_global_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_MISO), MP_ROM_PTR(&pin_PA12) },
     { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
     { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
+    { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
 };
 MP_DEFINE_CONST_DICT(board_module_globals, board_global_dict_table);
diff --git a/ports/atmel-samd/boards/circuitplayground_express/mpconfigboard.h b/ports/atmel-samd/boards/circuitplayground_express/mpconfigboard.h
index 320374cbbf..3d97e2cb19 100644
--- a/ports/atmel-samd/boards/circuitplayground_express/mpconfigboard.h
+++ b/ports/atmel-samd/boards/circuitplayground_express/mpconfigboard.h
@@ -65,3 +65,6 @@
 #define DEFAULT_SPI_BUS_SCK (&pin_PA05)
 #define DEFAULT_SPI_BUS_MOSI (&pin_PA07)
 #define DEFAULT_SPI_BUS_MISO (&pin_PA06)
+
+#define DEFAULT_UART_BUS_RX (&pin_PB09)
+#define DEFAULT_UART_BUS_TX (&pin_PB08)
diff --git a/ports/atmel-samd/boards/circuitplayground_express/pins.c b/ports/atmel-samd/boards/circuitplayground_express/pins.c
index 4f32ecafab..f4540573a8 100644
--- a/ports/atmel-samd/boards/circuitplayground_express/pins.c
+++ b/ports/atmel-samd/boards/circuitplayground_express/pins.c
@@ -59,5 +59,6 @@ STATIC const mp_rom_map_elem_t board_global_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_MISO), MP_ROM_PTR(&pin_PA06) },
     { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
     { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
+    { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
 };
 MP_DEFINE_CONST_DICT(board_module_globals, board_global_dict_table);
diff --git a/ports/atmel-samd/boards/feather_m0_adalogger/mpconfigboard.h b/ports/atmel-samd/boards/feather_m0_adalogger/mpconfigboard.h
index d38bfcdc87..94caa7d040 100644
--- a/ports/atmel-samd/boards/feather_m0_adalogger/mpconfigboard.h
+++ b/ports/atmel-samd/boards/feather_m0_adalogger/mpconfigboard.h
@@ -19,3 +19,6 @@
 #define DEFAULT_SPI_BUS_SCK (&pin_PB11)
 #define DEFAULT_SPI_BUS_MOSI (&pin_PB10)
 #define DEFAULT_SPI_BUS_MISO (&pin_PA12)
+
+#define DEFAULT_UART_BUS_RX (&pin_PA11)
+#define DEFAULT_UART_BUS_TX (&pin_PA10)
diff --git a/ports/atmel-samd/boards/feather_m0_adalogger/pins.c b/ports/atmel-samd/boards/feather_m0_adalogger/pins.c
index 1ae2d958a4..7eff106e82 100644
--- a/ports/atmel-samd/boards/feather_m0_adalogger/pins.c
+++ b/ports/atmel-samd/boards/feather_m0_adalogger/pins.c
@@ -33,5 +33,6 @@ STATIC const mp_rom_map_elem_t board_global_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_RED_LED), MP_ROM_PTR(&pin_PA17) },
     { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
     { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
+    { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
 };
 MP_DEFINE_CONST_DICT(board_module_globals, board_global_dict_table);
diff --git a/ports/atmel-samd/boards/feather_m0_basic/mpconfigboard.h b/ports/atmel-samd/boards/feather_m0_basic/mpconfigboard.h
index 0e66fb25e1..34de8e1660 100644
--- a/ports/atmel-samd/boards/feather_m0_basic/mpconfigboard.h
+++ b/ports/atmel-samd/boards/feather_m0_basic/mpconfigboard.h
@@ -20,3 +20,6 @@
 #define DEFAULT_SPI_BUS_SCK (&pin_PB11)
 #define DEFAULT_SPI_BUS_MOSI (&pin_PB10)
 #define DEFAULT_SPI_BUS_MISO (&pin_PA12)
+
+#define DEFAULT_UART_BUS_RX (&pin_PA11)
+#define DEFAULT_UART_BUS_TX (&pin_PA10)
diff --git a/ports/atmel-samd/boards/feather_m0_basic/pins.c b/ports/atmel-samd/boards/feather_m0_basic/pins.c
index 1bd283bab3..b3edabe812 100644
--- a/ports/atmel-samd/boards/feather_m0_basic/pins.c
+++ b/ports/atmel-samd/boards/feather_m0_basic/pins.c
@@ -26,5 +26,6 @@ STATIC const mp_rom_map_elem_t board_global_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_D13), MP_ROM_PTR(&pin_PA17) },
     { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
     { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
+    { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
 };
 MP_DEFINE_CONST_DICT(board_module_globals, board_global_dict_table);
diff --git a/ports/atmel-samd/boards/feather_m0_express/mpconfigboard.h b/ports/atmel-samd/boards/feather_m0_express/mpconfigboard.h
index bc4a9d825c..bfa8c642a2 100644
--- a/ports/atmel-samd/boards/feather_m0_express/mpconfigboard.h
+++ b/ports/atmel-samd/boards/feather_m0_express/mpconfigboard.h
@@ -55,3 +55,6 @@
 #define DEFAULT_SPI_BUS_SCK (&pin_PB11)
 #define DEFAULT_SPI_BUS_MOSI (&pin_PB10)
 #define DEFAULT_SPI_BUS_MISO (&pin_PA12)
+
+#define DEFAULT_UART_BUS_RX (&pin_PA11)
+#define DEFAULT_UART_BUS_TX (&pin_PA10)
diff --git a/ports/atmel-samd/boards/feather_m0_express/pins.c b/ports/atmel-samd/boards/feather_m0_express/pins.c
index 395a84d551..6bd74f3729 100644
--- a/ports/atmel-samd/boards/feather_m0_express/pins.c
+++ b/ports/atmel-samd/boards/feather_m0_express/pins.c
@@ -27,5 +27,6 @@ STATIC const mp_rom_map_elem_t board_global_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_NEOPIXEL), MP_ROM_PTR(&pin_PA06) },
     { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
     { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
+    { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
 };
 MP_DEFINE_CONST_DICT(board_module_globals, board_global_dict_table);
diff --git a/ports/atmel-samd/boards/feather_m0_rfm69/mpconfigboard.h b/ports/atmel-samd/boards/feather_m0_rfm69/mpconfigboard.h
index fd5e026953..4f4ea2ffea 100644
--- a/ports/atmel-samd/boards/feather_m0_rfm69/mpconfigboard.h
+++ b/ports/atmel-samd/boards/feather_m0_rfm69/mpconfigboard.h
@@ -20,3 +20,6 @@
 #define DEFAULT_SPI_BUS_SCK (&pin_PB11)
 #define DEFAULT_SPI_BUS_MOSI (&pin_PB10)
 #define DEFAULT_SPI_BUS_MISO (&pin_PA12)
+
+#define DEFAULT_UART_BUS_RX (&pin_PA11)
+#define DEFAULT_UART_BUS_TX (&pin_PA10)
diff --git a/ports/atmel-samd/boards/feather_m0_rfm69/pins.c b/ports/atmel-samd/boards/feather_m0_rfm69/pins.c
index 1c6051a5c4..e6cede3dd9 100644
--- a/ports/atmel-samd/boards/feather_m0_rfm69/pins.c
+++ b/ports/atmel-samd/boards/feather_m0_rfm69/pins.c
@@ -29,5 +29,6 @@ STATIC const mp_rom_map_elem_t board_global_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_RFM69_CS), MP_ROM_PTR(&pin_PA06) },
     { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
     { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
+    { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
 };
 MP_DEFINE_CONST_DICT(board_module_globals, board_global_dict_table);
diff --git a/ports/atmel-samd/boards/feather_m0_rfm9x/mpconfigboard.h b/ports/atmel-samd/boards/feather_m0_rfm9x/mpconfigboard.h
index 511c9c5e18..a9d586c2e3 100644
--- a/ports/atmel-samd/boards/feather_m0_rfm9x/mpconfigboard.h
+++ b/ports/atmel-samd/boards/feather_m0_rfm9x/mpconfigboard.h
@@ -20,3 +20,6 @@
 #define DEFAULT_SPI_BUS_SCK (&pin_PB11)
 #define DEFAULT_SPI_BUS_MOSI (&pin_PB10)
 #define DEFAULT_SPI_BUS_MISO (&pin_PA12)
+
+#define DEFAULT_UART_BUS_RX (&pin_PA11)
+#define DEFAULT_UART_BUS_TX (&pin_PA10)
diff --git a/ports/atmel-samd/boards/feather_m0_rfm9x/pins.c b/ports/atmel-samd/boards/feather_m0_rfm9x/pins.c
index addb700e42..8f52a5767c 100644
--- a/ports/atmel-samd/boards/feather_m0_rfm9x/pins.c
+++ b/ports/atmel-samd/boards/feather_m0_rfm9x/pins.c
@@ -29,5 +29,6 @@ STATIC const mp_rom_map_elem_t board_global_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_RFM9X_CS), MP_ROM_PTR(&pin_PA06) },
     { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
     { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
+    { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
 };
 MP_DEFINE_CONST_DICT(board_module_globals, board_global_dict_table);
diff --git a/ports/atmel-samd/boards/feather_m0_supersized/mpconfigboard.h b/ports/atmel-samd/boards/feather_m0_supersized/mpconfigboard.h
index cbbe8b8f2c..c8118e48b4 100644
--- a/ports/atmel-samd/boards/feather_m0_supersized/mpconfigboard.h
+++ b/ports/atmel-samd/boards/feather_m0_supersized/mpconfigboard.h
@@ -54,3 +54,6 @@
 #define DEFAULT_SPI_BUS_SCK (&pin_PB11)
 #define DEFAULT_SPI_BUS_MOSI (&pin_PB10)
 #define DEFAULT_SPI_BUS_MISO (&pin_PA12)
+
+#define DEFAULT_UART_BUS_RX (&pin_PA11)
+#define DEFAULT_UART_BUS_TX (&pin_PA10)
diff --git a/ports/atmel-samd/boards/feather_m0_supersized/pins.c b/ports/atmel-samd/boards/feather_m0_supersized/pins.c
index 395a84d551..6bd74f3729 100644
--- a/ports/atmel-samd/boards/feather_m0_supersized/pins.c
+++ b/ports/atmel-samd/boards/feather_m0_supersized/pins.c
@@ -27,5 +27,6 @@ STATIC const mp_rom_map_elem_t board_global_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_NEOPIXEL), MP_ROM_PTR(&pin_PA06) },
     { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
     { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
+    { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
 };
 MP_DEFINE_CONST_DICT(board_module_globals, board_global_dict_table);
diff --git a/ports/atmel-samd/boards/feather_m4_express/mpconfigboard.h b/ports/atmel-samd/boards/feather_m4_express/mpconfigboard.h
index f3dc24feef..3c1895dd24 100644
--- a/ports/atmel-samd/boards/feather_m4_express/mpconfigboard.h
+++ b/ports/atmel-samd/boards/feather_m4_express/mpconfigboard.h
@@ -38,3 +38,6 @@
 #define DEFAULT_SPI_BUS_SCK (&pin_PA17)
 #define DEFAULT_SPI_BUS_MOSI (&pin_PA19)
 #define DEFAULT_SPI_BUS_MISO (&pin_PA18)
+
+#define DEFAULT_UART_BUS_RX (&pin_PA07)
+#define DEFAULT_UART_BUS_TX (&pin_PA04)
diff --git a/ports/atmel-samd/boards/feather_m4_express/pins.c b/ports/atmel-samd/boards/feather_m4_express/pins.c
index 99c344638e..6807a901d5 100644
--- a/ports/atmel-samd/boards/feather_m4_express/pins.c
+++ b/ports/atmel-samd/boards/feather_m4_express/pins.c
@@ -29,5 +29,6 @@ STATIC const mp_rom_map_elem_t board_global_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_NEOPIXEL), MP_ROM_PTR(&pin_PB23) },
     { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
     { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
+    { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
 };
 MP_DEFINE_CONST_DICT(board_module_globals, board_global_dict_table);
diff --git a/ports/atmel-samd/boards/gemma_m0/mpconfigboard.h b/ports/atmel-samd/boards/gemma_m0/mpconfigboard.h
index 2527b9d069..53e802f172 100644
--- a/ports/atmel-samd/boards/gemma_m0/mpconfigboard.h
+++ b/ports/atmel-samd/boards/gemma_m0/mpconfigboard.h
@@ -15,6 +15,9 @@
 #define DEFAULT_I2C_BUS_SCL (&pin_PA05)
 #define DEFAULT_I2C_BUS_SDA (&pin_PA04)
 
+#define DEFAULT_UART_BUS_RX (&pin_PA05)
+#define DEFAULT_UART_BUS_TX (&pin_PA04)
+
 #include "internal_flash.h"
 
 #define BOARD_FLASH_SIZE (0x00040000 - 0x2000 - 0x010000)
diff --git a/ports/atmel-samd/boards/gemma_m0/pins.c b/ports/atmel-samd/boards/gemma_m0/pins.c
index 9fe2bbd6f2..6d031c6854 100644
--- a/ports/atmel-samd/boards/gemma_m0/pins.c
+++ b/ports/atmel-samd/boards/gemma_m0/pins.c
@@ -22,5 +22,6 @@ STATIC const mp_rom_map_elem_t board_global_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_APA102_SCK),  MP_ROM_PTR(&pin_PA01) },
     { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
     { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
+    { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
 };
 MP_DEFINE_CONST_DICT(board_module_globals, board_global_dict_table);
diff --git a/ports/atmel-samd/boards/itsybitsy_m0_express/mpconfigboard.h b/ports/atmel-samd/boards/itsybitsy_m0_express/mpconfigboard.h
index 14efd46022..be59bc5d4a 100644
--- a/ports/atmel-samd/boards/itsybitsy_m0_express/mpconfigboard.h
+++ b/ports/atmel-samd/boards/itsybitsy_m0_express/mpconfigboard.h
@@ -53,3 +53,6 @@
 #define DEFAULT_SPI_BUS_SCK (&pin_PB11)
 #define DEFAULT_SPI_BUS_MOSI (&pin_PB10)
 #define DEFAULT_SPI_BUS_MISO (&pin_PA12)
+
+#define DEFAULT_UART_BUS_RX (&pin_PA11)
+#define DEFAULT_UART_BUS_TX (&pin_PA10)
diff --git a/ports/atmel-samd/boards/itsybitsy_m0_express/pins.c b/ports/atmel-samd/boards/itsybitsy_m0_express/pins.c
index a2f19501d4..2b35c91aad 100644
--- a/ports/atmel-samd/boards/itsybitsy_m0_express/pins.c
+++ b/ports/atmel-samd/boards/itsybitsy_m0_express/pins.c
@@ -41,5 +41,6 @@ STATIC const mp_rom_map_elem_t board_global_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_APA102_SCK), MP_ROM_PTR(&pin_PA00) },
     { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
     { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
+    { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
 };
 MP_DEFINE_CONST_DICT(board_module_globals, board_global_dict_table);
diff --git a/ports/atmel-samd/boards/itsybitsy_m4_express/mpconfigboard.h b/ports/atmel-samd/boards/itsybitsy_m4_express/mpconfigboard.h
index db6ea09b31..faa0d6e754 100644
--- a/ports/atmel-samd/boards/itsybitsy_m4_express/mpconfigboard.h
+++ b/ports/atmel-samd/boards/itsybitsy_m4_express/mpconfigboard.h
@@ -38,3 +38,6 @@
 #define DEFAULT_SPI_BUS_SCK (&pin_PA01)
 #define DEFAULT_SPI_BUS_MOSI (&pin_PA00)
 #define DEFAULT_SPI_BUS_MISO (&pin_PB23)
+
+#define DEFAULT_UART_BUS_RX (&pin_PA16)
+#define DEFAULT_UART_BUS_TX (&pin_PA17)
diff --git a/ports/atmel-samd/boards/itsybitsy_m4_express/pins.c b/ports/atmel-samd/boards/itsybitsy_m4_express/pins.c
index bb235aed1d..084250b311 100644
--- a/ports/atmel-samd/boards/itsybitsy_m4_express/pins.c
+++ b/ports/atmel-samd/boards/itsybitsy_m4_express/pins.c
@@ -38,5 +38,6 @@ STATIC const mp_rom_map_elem_t board_global_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_APA102_SCK), MP_ROM_PTR(&pin_PB02) },
     { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
     { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
+    { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
 };
 MP_DEFINE_CONST_DICT(board_module_globals, board_global_dict_table);
diff --git a/ports/atmel-samd/boards/metro_m0_express/mpconfigboard.h b/ports/atmel-samd/boards/metro_m0_express/mpconfigboard.h
index f1c278023b..f798c5d365 100644
--- a/ports/atmel-samd/boards/metro_m0_express/mpconfigboard.h
+++ b/ports/atmel-samd/boards/metro_m0_express/mpconfigboard.h
@@ -56,3 +56,6 @@
 #define DEFAULT_SPI_BUS_SCK (&pin_PB11)
 #define DEFAULT_SPI_BUS_MOSI (&pin_PB10)
 #define DEFAULT_SPI_BUS_MISO (&pin_PA12)
+
+#define DEFAULT_UART_BUS_RX (&pin_PA11)
+#define DEFAULT_UART_BUS_TX (&pin_PA10)
diff --git a/ports/atmel-samd/boards/metro_m0_express/pins.c b/ports/atmel-samd/boards/metro_m0_express/pins.c
index 458b01bb5b..4cd8752bea 100644
--- a/ports/atmel-samd/boards/metro_m0_express/pins.c
+++ b/ports/atmel-samd/boards/metro_m0_express/pins.c
@@ -32,5 +32,6 @@ STATIC const mp_rom_map_elem_t board_global_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_MISO), MP_ROM_PTR(&pin_PA12) },
     { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
     { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
+    { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
 };
 MP_DEFINE_CONST_DICT(board_module_globals, board_global_dict_table);
diff --git a/ports/atmel-samd/boards/metro_m4_express/mpconfigboard.h b/ports/atmel-samd/boards/metro_m4_express/mpconfigboard.h
index 9bc8c8b006..cda43d95e6 100644
--- a/ports/atmel-samd/boards/metro_m4_express/mpconfigboard.h
+++ b/ports/atmel-samd/boards/metro_m4_express/mpconfigboard.h
@@ -39,3 +39,6 @@
 #define DEFAULT_SPI_BUS_SCK (&pin_PA13)
 #define DEFAULT_SPI_BUS_MOSI (&pin_PA12)
 #define DEFAULT_SPI_BUS_MISO (&pin_PA14)
+
+#define DEFAULT_UART_BUS_RX (&pin_PA23)
+#define DEFAULT_UART_BUS_TX (&pin_PA22)
diff --git a/ports/atmel-samd/boards/metro_m4_express/pins.c b/ports/atmel-samd/boards/metro_m4_express/pins.c
index 3d509fa53f..95a97d825f 100644
--- a/ports/atmel-samd/boards/metro_m4_express/pins.c
+++ b/ports/atmel-samd/boards/metro_m4_express/pins.c
@@ -44,5 +44,6 @@ STATIC const mp_map_elem_t board_global_dict_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_LED_TX), (mp_obj_t)&pin_PA27 },
     { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
     { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
+    { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
 };
 MP_DEFINE_CONST_DICT(board_module_globals, board_global_dict_table);
diff --git a/ports/atmel-samd/boards/metro_m4_express_revb/mpconfigboard.h b/ports/atmel-samd/boards/metro_m4_express_revb/mpconfigboard.h
index ee85138a7b..db51140d66 100644
--- a/ports/atmel-samd/boards/metro_m4_express_revb/mpconfigboard.h
+++ b/ports/atmel-samd/boards/metro_m4_express_revb/mpconfigboard.h
@@ -67,3 +67,6 @@
 #define DEFAULT_SPI_BUS_SCK (&pin_PA13)
 #define DEFAULT_SPI_BUS_MOSI (&pin_PA12)
 #define DEFAULT_SPI_BUS_MISO (&pin_PA15)
+
+#define DEFAULT_UART_BUS_RX (&pin_PA23)
+#define DEFAULT_UART_BUS_TX (&pin_PA22)
diff --git a/ports/atmel-samd/boards/metro_m4_express_revb/pins.c b/ports/atmel-samd/boards/metro_m4_express_revb/pins.c
index a7b4d25b20..23e662f1c3 100644
--- a/ports/atmel-samd/boards/metro_m4_express_revb/pins.c
+++ b/ports/atmel-samd/boards/metro_m4_express_revb/pins.c
@@ -43,5 +43,6 @@ STATIC const mp_map_elem_t board_global_dict_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_LED_TX), (mp_obj_t)&pin_PA27 },
     { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
     { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
+    { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
 };
 MP_DEFINE_CONST_DICT(board_module_globals, board_global_dict_table);
diff --git a/ports/atmel-samd/boards/pirkey_m0/pins.c b/ports/atmel-samd/boards/pirkey_m0/pins.c
index b8e9371966..7efc8eb33f 100644
--- a/ports/atmel-samd/boards/pirkey_m0/pins.c
+++ b/ports/atmel-samd/boards/pirkey_m0/pins.c
@@ -8,5 +8,6 @@ STATIC const mp_rom_map_elem_t board_global_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_APA102_SCK),  MP_ROM_PTR(&pin_PA01) },
     { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
     { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
+    { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
 };
 MP_DEFINE_CONST_DICT(board_module_globals, board_global_dict_table);
diff --git a/ports/atmel-samd/boards/trinket_m0/mpconfigboard.h b/ports/atmel-samd/boards/trinket_m0/mpconfigboard.h
index 0ce7962191..d561947e39 100644
--- a/ports/atmel-samd/boards/trinket_m0/mpconfigboard.h
+++ b/ports/atmel-samd/boards/trinket_m0/mpconfigboard.h
@@ -63,3 +63,6 @@
 #define DEFAULT_SPI_BUS_SCK (&pin_PA07)
 #define DEFAULT_SPI_BUS_MOSI (&pin_PA06)
 #define DEFAULT_SPI_BUS_MISO (&pin_PA09)
+
+#define DEFAULT_UART_BUS_RX (&pin_PA07)
+#define DEFAULT_UART_BUS_TX (&pin_PA06)
diff --git a/ports/atmel-samd/boards/trinket_m0/pins.c b/ports/atmel-samd/boards/trinket_m0/pins.c
index 424b8f75aa..0fdcbc2790 100644
--- a/ports/atmel-samd/boards/trinket_m0/pins.c
+++ b/ports/atmel-samd/boards/trinket_m0/pins.c
@@ -30,5 +30,6 @@ STATIC const mp_rom_map_elem_t board_global_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_APA102_SCK), MP_ROM_PTR(&pin_PA01) },
     { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
     { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
+    { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
 };
 MP_DEFINE_CONST_DICT(board_module_globals, board_global_dict_table);
diff --git a/ports/atmel-samd/boards/trinket_m0_haxpress/mpconfigboard.h b/ports/atmel-samd/boards/trinket_m0_haxpress/mpconfigboard.h
index 4a635a6df3..3377d1b7ea 100644
--- a/ports/atmel-samd/boards/trinket_m0_haxpress/mpconfigboard.h
+++ b/ports/atmel-samd/boards/trinket_m0_haxpress/mpconfigboard.h
@@ -61,3 +61,6 @@
 #define DEFAULT_SPI_BUS_SCK (&pin_PA07)
 #define DEFAULT_SPI_BUS_MOSI (&pin_PA06)
 #define DEFAULT_SPI_BUS_MISO (&pin_PA09)
+
+#define DEFAULT_UART_BUS_RX (&pin_PA07)
+#define DEFAULT_UART_BUS_TX (&pin_PA06)
diff --git a/ports/atmel-samd/boards/trinket_m0_haxpress/pins.c b/ports/atmel-samd/boards/trinket_m0_haxpress/pins.c
index 424b8f75aa..0fdcbc2790 100644
--- a/ports/atmel-samd/boards/trinket_m0_haxpress/pins.c
+++ b/ports/atmel-samd/boards/trinket_m0_haxpress/pins.c
@@ -30,5 +30,6 @@ STATIC const mp_rom_map_elem_t board_global_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_APA102_SCK), MP_ROM_PTR(&pin_PA01) },
     { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
     { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
+    { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
 };
 MP_DEFINE_CONST_DICT(board_module_globals, board_global_dict_table);
diff --git a/ports/atmel-samd/boards/ugame10/pins.c b/ports/atmel-samd/boards/ugame10/pins.c
index 80051b550b..acf73c9ffc 100644
--- a/ports/atmel-samd/boards/ugame10/pins.c
+++ b/ports/atmel-samd/boards/ugame10/pins.c
@@ -26,5 +26,6 @@ STATIC const mp_rom_map_elem_t board_global_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_D), MP_ROM_PTR(&pin_PA28) },
     { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
     { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
+    { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
 };
 MP_DEFINE_CONST_DICT(board_module_globals, board_global_dict_table);