diff --git a/locale/circuitpython.pot b/locale/circuitpython.pot
index 0a4303f66a..14049eaef7 100644
--- a/locale/circuitpython.pot
+++ b/locale/circuitpython.pot
@@ -17,6 +17,13 @@ msgstr ""
 "Content-Type: text/plain; charset=CHARSET\n"
 "Content-Transfer-Encoding: 8bit\n"
 
+#: main.c
+msgid ""
+"\n"
+"\n"
+"------ soft reboot ------\n"
+msgstr ""
+
 #: main.c
 msgid ""
 "\n"
@@ -982,6 +989,10 @@ msgstr ""
 msgid "I2SOut not available"
 msgstr ""
 
+#: ports/esp32s2/common-hal/alarm_io/__init__.c
+msgid "IOs 0, 2 & 4 do not support internal pullup in sleep"
+msgstr ""
+
 #: shared-bindings/aesio/aes.c
 #, c-format
 msgid "IV must be %d bytes long"
@@ -2793,6 +2804,10 @@ msgstr ""
 msgid "invalid syntax for number"
 msgstr ""
 
+#: ports/esp32s2/common-hal/alarm_io/__init__.c
+msgid "io must be rtc io"
+msgstr ""
+
 #: py/objtype.c
 msgid "issubclass() arg 1 must be a class"
 msgstr ""
@@ -3313,7 +3328,7 @@ msgstr ""
 msgid "size is defined for ndarrays only"
 msgstr ""
 
-#: shared-bindings/time/__init__.c
+#: shared-bindings/alarm_time/__init__.c shared-bindings/time/__init__.c
 msgid "sleep length must be non-negative"
 msgstr ""
 
@@ -3329,10 +3344,6 @@ msgstr ""
 msgid "small int overflow"
 msgstr ""
 
-#: main.c
-msgid "soft reboot\n"
-msgstr ""
-
 #: extmod/ulab/code/numerical/numerical.c
 msgid "sort argument must be an ndarray"
 msgstr ""
@@ -3417,6 +3428,10 @@ msgstr ""
 msgid "threshold must be in the range 0-65536"
 msgstr ""
 
+#: ports/esp32s2/common-hal/alarm_time/__init__.c
+msgid "time out of range"
+msgstr ""
+
 #: shared-bindings/time/__init__.c
 msgid "time.struct_time() takes a 9-sequence"
 msgstr ""
@@ -3462,6 +3477,10 @@ msgstr ""
 msgid "trapz is defined for 1D arrays of equal length"
 msgstr ""
 
+#: ports/esp32s2/common-hal/alarm_io/__init__.c
+msgid "trigger level must be 0 or 1"
+msgstr ""
+
 #: extmod/ulab/code/linalg/linalg.c
 msgid "tuple index out of range"
 msgstr ""
@@ -3604,6 +3623,10 @@ msgstr ""
 msgid "vectors must have same lengths"
 msgstr ""
 
+#: ports/esp32s2/common-hal/alarm_io/__init__.c
+msgid "wakeup conflict"
+msgstr ""
+
 #: shared-bindings/watchdog/WatchDogTimer.c
 msgid "watchdog timeout must be greater than 0"
 msgstr ""
diff --git a/main.c b/main.c
index 80b163f607..a200b62641 100755
--- a/main.c
+++ b/main.c
@@ -57,6 +57,9 @@
 #include "supervisor/shared/status_leds.h"
 #include "supervisor/shared/stack.h"
 #include "supervisor/serial.h"
+#include "supervisor/usb.h"
+
+#include "shared-bindings/microcontroller/__init__.h"
 
 #include "boards/board.h"
 
@@ -85,6 +88,10 @@
 #include "common-hal/canio/CAN.h"
 #endif
 
+#if CIRCUITPY_SLEEP
+#include "shared-bindings/sleep/__init__.h"
+#endif
+
 void do_str(const char *src, mp_parse_input_kind_t input_kind) {
     mp_lexer_t *lex = mp_lexer_new_from_str_len(MP_QSTR__lt_stdin_gt_, src, strlen(src), 0);
     if (lex == NULL) {
@@ -312,6 +319,14 @@ bool run_code_py(safe_mode_t safe_mode) {
     bool refreshed_epaper_display = false;
     #endif
     rgb_status_animation_t animation;
+    bool ok = result->return_code != PYEXEC_EXCEPTION;
+    #if CIRCUITPY_SLEEP
+    // If USB isn't enumerated then deep sleep.
+    if (ok && !supervisor_workflow_active() && supervisor_ticks_ms64() > CIRCUITPY_USB_ENUMERATION_DELAY * 1024) {
+        common_hal_sleep_deep_sleep();
+    }
+    #endif
+    // Show the animation every N seconds.
     prep_rgb_status_animation(&result, found_main, safe_mode, &animation);
     while (true) {
         RUN_BACKGROUND_TASKS;
@@ -344,8 +359,24 @@ bool run_code_py(safe_mode_t safe_mode) {
             refreshed_epaper_display = maybe_refresh_epaperdisplay();
         }
         #endif
-
-        tick_rgb_status_animation(&animation);
+        bool animation_done = tick_rgb_status_animation(&animation);
+        if (animation_done && supervisor_workflow_active()) {
+            #if CIRCUITPY_SLEEP
+            int64_t remaining_enumeration_wait = CIRCUITPY_USB_ENUMERATION_DELAY * 1024 - supervisor_ticks_ms64();
+            // If USB isn't enumerated then deep sleep after our waiting period.
+            if (ok && remaining_enumeration_wait < 0) {
+                common_hal_sleep_deep_sleep();
+                return; // Doesn't actually get here.
+            }
+            #endif
+            // Wake up every so often to flash the error code.
+            if (!ok) {
+                port_interrupt_after_ticks(CIRCUITPY_FLASH_ERROR_PERIOD * 1024);
+            } else {
+                port_interrupt_after_ticks(remaining_enumeration_wait);
+            }
+            port_sleep_until_interrupt();
+        }
     }
 }
 
@@ -392,7 +423,9 @@ void __attribute__ ((noinline)) run_boot_py(safe_mode_t safe_mode) {
         if (!skip_boot_output) {
             // Wait 1.5 seconds before opening CIRCUITPY_BOOT_OUTPUT_FILE for write,
             // in case power is momentary or will fail shortly due to, say a low, battery.
-            mp_hal_delay_ms(1500);
+            if (common_hal_sleep_get_reset_reason() == RESET_REASON_POWER_VALID) {
+                mp_hal_delay_ms(1500);
+            }
 
             // USB isn't up, so we can write the file.
             filesystem_set_internal_writable_by_usb(false);
@@ -511,7 +544,7 @@ int __attribute__((used)) main(void) {
         }
         if (exit_code == PYEXEC_FORCED_EXIT) {
             if (!first_run) {
-                serial_write_compressed(translate("soft reboot\n"));
+                serial_write_compressed(translate("\n\n------ soft reboot ------\n"));
             }
             first_run = false;
             skip_repl = run_code_py(safe_mode);
diff --git a/ports/atmel-samd/common-hal/microcontroller/__init__.c b/ports/atmel-samd/common-hal/microcontroller/__init__.c
index 50a1ec038e..ca39f28386 100644
--- a/ports/atmel-samd/common-hal/microcontroller/__init__.c
+++ b/ports/atmel-samd/common-hal/microcontroller/__init__.c
@@ -84,6 +84,10 @@ void common_hal_mcu_reset(void) {
     reset();
 }
 
+void common_hal_mcu_deep_sleep(void) {
+    //deep sleep call here
+}
+
 // The singleton microcontroller.Processor object, bound to microcontroller.cpu
 // It currently only has properties, and no state.
 const mcu_processor_obj_t common_hal_mcu_processor_obj = {
diff --git a/ports/cxd56/common-hal/microcontroller/__init__.c b/ports/cxd56/common-hal/microcontroller/__init__.c
index 7aa3b839d7..57140dec70 100644
--- a/ports/cxd56/common-hal/microcontroller/__init__.c
+++ b/ports/cxd56/common-hal/microcontroller/__init__.c
@@ -81,6 +81,10 @@ void common_hal_mcu_reset(void) {
     boardctl(BOARDIOC_RESET, 0);
 }
 
+void common_hal_mcu_deep_sleep(void) {
+    //deep sleep call here
+}
+
 STATIC const mp_rom_map_elem_t mcu_pin_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_UART2_RXD), MP_ROM_PTR(&pin_UART2_RXD) },
     { MP_ROM_QSTR(MP_QSTR_UART2_TXD), MP_ROM_PTR(&pin_UART2_TXD) },
diff --git a/ports/esp32s2/common-hal/alarm/__init__.c b/ports/esp32s2/common-hal/alarm/__init__.c
new file mode 100644
index 0000000000..552ad4452b
--- /dev/null
+++ b/ports/esp32s2/common-hal/alarm/__init__.c
@@ -0,0 +1,60 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2016 Scott Shawcroft for Adafruit Industries
+ * Copyright (c) 2019 Lucian Copeland for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "shared-bindings/alarm/__init__.h"
+#include "shared-bindings/alarm_io/__init__.h"
+#include "shared-bindings/alarm_time/__init__.h"
+
+#include "esp_sleep.h"
+
+void common_hal_alarm_disable_all(void) {
+    esp_sleep_disable_wakeup_source(ESP_SLEEP_WAKEUP_ALL);
+}
+
+mp_obj_t common_hal_alarm_get_wake_alarm(void) {
+    switch (esp_sleep_get_wakeup_cause()) {
+        case ESP_SLEEP_WAKEUP_TIMER: ;
+            //Wake up from timer.
+            alarm_time_obj_t *timer = m_new_obj(alarm_time_obj_t);
+            timer->base.type = &alarm_time_type;
+            return timer;
+        case ESP_SLEEP_WAKEUP_EXT0: ;
+            //Wake up from GPIO
+            alarm_io_obj_t *ext0 = m_new_obj(alarm_io_obj_t);
+            ext0->base.type = &alarm_io_type;
+            return ext0;
+        case ESP_SLEEP_WAKEUP_TOUCHPAD:
+            //TODO: implement TouchIO
+            //Wake up from touch on pad, esp_sleep_get_touchpad_wakeup_status()
+            break;
+        case ESP_SLEEP_WAKEUP_UNDEFINED:
+        default:
+            //Not a deep sleep reset
+            break;
+    }
+    return mp_const_none;
+}
diff --git a/ports/esp32s2/common-hal/alarm_io/__init__.c b/ports/esp32s2/common-hal/alarm_io/__init__.c
new file mode 100644
index 0000000000..b39693c6af
--- /dev/null
+++ b/ports/esp32s2/common-hal/alarm_io/__init__.c
@@ -0,0 +1,35 @@
+#include "shared-bindings/alarm_io/__init__.h"
+
+#include "esp_sleep.h"
+#include "driver/rtc_io.h"
+
+mp_obj_t common_hal_alarm_io_pin_state (alarm_io_obj_t *self_in) {
+    if (!rtc_gpio_is_valid_gpio(self_in->gpio)) {
+        mp_raise_ValueError(translate("io must be rtc io"));
+    }
+
+    if (self_in->pull && !self_in->level) {
+        for (uint8_t i = 0; i<=4; i+=2) {
+            if (self_in->gpio == i) {
+                mp_raise_ValueError(translate("IOs 0, 2 & 4 do not support internal pullup in sleep"));
+            }
+        }
+    }
+
+    switch(esp_sleep_enable_ext0_wakeup(self_in->gpio, self_in->level)) {
+        case ESP_ERR_INVALID_ARG:
+            mp_raise_ValueError(translate("trigger level must be 0 or 1"));
+        case ESP_ERR_INVALID_STATE:
+            mp_raise_RuntimeError(translate("wakeup conflict"));
+        default:
+            break;
+    }
+
+    if (self_in->pull) { (self_in->level) ? rtc_gpio_pulldown_en(self_in->gpio) : rtc_gpio_pullup_en(self_in->gpio); }
+
+    return self_in;
+}
+
+void common_hal_alarm_io_disable (void) {
+    esp_sleep_disable_wakeup_source(ESP_SLEEP_WAKEUP_EXT0 | ESP_SLEEP_WAKEUP_EXT1);
+}
diff --git a/ports/esp32s2/common-hal/alarm_time/__init__.c b/ports/esp32s2/common-hal/alarm_time/__init__.c
new file mode 100644
index 0000000000..252b6e107c
--- /dev/null
+++ b/ports/esp32s2/common-hal/alarm_time/__init__.c
@@ -0,0 +1,13 @@
+#include "esp_sleep.h"
+
+#include "shared-bindings/alarm_time/__init__.h"
+
+void common_hal_alarm_time_duration (uint32_t ms) {
+    if (esp_sleep_enable_timer_wakeup((ms) * 1000) == ESP_ERR_INVALID_ARG) {
+        mp_raise_ValueError(translate("time out of range"));
+    }
+}
+
+void common_hal_alarm_time_disable (void) {
+    esp_sleep_disable_wakeup_source(ESP_SLEEP_WAKEUP_TIMER);
+}
diff --git a/ports/esp32s2/common-hal/microcontroller/__init__.c b/ports/esp32s2/common-hal/microcontroller/__init__.c
index 6b2e18673d..ab0e1bfaa4 100644
--- a/ports/esp32s2/common-hal/microcontroller/__init__.c
+++ b/ports/esp32s2/common-hal/microcontroller/__init__.c
@@ -25,8 +25,8 @@
  * THE SOFTWARE.
  */
 
-#include "py/mphal.h"
 #include "py/obj.h"
+#include "py/mphal.h"
 #include "py/runtime.h"
 
 #include "common-hal/microcontroller/Pin.h"
@@ -41,6 +41,8 @@
 
 #include "freertos/FreeRTOS.h"
 
+#include "esp_sleep.h"
+
 void common_hal_mcu_delay_us(uint32_t delay) {
 
 }
@@ -77,6 +79,10 @@ void common_hal_mcu_reset(void) {
     while(1);
 }
 
+void common_hal_mcu_deep_sleep(void) {
+    esp_deep_sleep_start();
+}
+
 // The singleton microcontroller.Processor object, bound to microcontroller.cpu
 // It currently only has properties, and no state.
 const mcu_processor_obj_t common_hal_mcu_processor_obj = {
diff --git a/ports/esp32s2/mpconfigport.mk b/ports/esp32s2/mpconfigport.mk
index 4579b95ab6..af1db2b2bf 100644
--- a/ports/esp32s2/mpconfigport.mk
+++ b/ports/esp32s2/mpconfigport.mk
@@ -14,6 +14,10 @@ LONGINT_IMPL = MPZ
 
 # These modules are implemented in ports/<port>/common-hal:
 CIRCUITPY_FULL_BUILD = 1
+CIRCUITPY_ALARM = 1
+CIRCUITPY_ALARM_IO = 1
+CIRCUITPY_ALARM_TIME = 1
+CIRCUITPY_ALARM_TOUCH = 1
 CIRCUITPY_AUDIOBUSIO = 0
 CIRCUITPY_AUDIOIO = 0
 CIRCUITPY_CANIO = 1
@@ -22,6 +26,7 @@ CIRCUITPY_FREQUENCYIO = 0
 CIRCUITPY_I2CPERIPHERAL = 0
 CIRCUITPY_ROTARYIO = 1
 CIRCUITPY_NVM = 0
+
 # We don't have enough endpoints to include MIDI.
 CIRCUITPY_USB_MIDI = 0
 CIRCUITPY_WIFI = 1
diff --git a/ports/esp32s2/supervisor/port.c b/ports/esp32s2/supervisor/port.c
index ef032c4a76..f253684725 100644
--- a/ports/esp32s2/supervisor/port.c
+++ b/ports/esp32s2/supervisor/port.c
@@ -36,13 +36,13 @@
 #include "freertos/FreeRTOS.h"
 #include "freertos/task.h"
 
-#include "common-hal/microcontroller/Pin.h"
 #include "common-hal/analogio/AnalogOut.h"
 #include "common-hal/busio/I2C.h"
 #include "common-hal/busio/SPI.h"
 #include "common-hal/busio/UART.h"
-#include "common-hal/pulseio/PulseIn.h"
 #include "common-hal/pwmio/PWMOut.h"
+#include "common-hal/pulseio/PulseIn.h"
+#include "common-hal/microcontroller/Pin.h"
 #include "common-hal/wifi/__init__.h"
 #include "supervisor/memory.h"
 #include "supervisor/shared/tick.h"
diff --git a/ports/litex/common-hal/microcontroller/__init__.c b/ports/litex/common-hal/microcontroller/__init__.c
index 3c91661144..e6f50ed5a6 100644
--- a/ports/litex/common-hal/microcontroller/__init__.c
+++ b/ports/litex/common-hal/microcontroller/__init__.c
@@ -89,6 +89,10 @@ void common_hal_mcu_reset(void) {
     while(1);
 }
 
+void common_hal_mcu_deep_sleep(void) {
+    //deep sleep call here
+}
+
 // The singleton microcontroller.Processor object, bound to microcontroller.cpu
 // It currently only has properties, and no state.
 const mcu_processor_obj_t common_hal_mcu_processor_obj = {
diff --git a/ports/mimxrt10xx/common-hal/microcontroller/__init__.c b/ports/mimxrt10xx/common-hal/microcontroller/__init__.c
index 6a8537e2da..0329ced69b 100644
--- a/ports/mimxrt10xx/common-hal/microcontroller/__init__.c
+++ b/ports/mimxrt10xx/common-hal/microcontroller/__init__.c
@@ -86,6 +86,10 @@ void common_hal_mcu_reset(void) {
     NVIC_SystemReset();
 }
 
+void common_hal_mcu_deep_sleep(void) {
+    //deep sleep call here
+}
+
 // The singleton microcontroller.Processor object, bound to microcontroller.cpu
 // It currently only has properties, and no state.
 const mcu_processor_obj_t common_hal_mcu_processor_obj = {
diff --git a/ports/nrf/common-hal/microcontroller/__init__.c b/ports/nrf/common-hal/microcontroller/__init__.c
index 06aac9409d..9911896bff 100644
--- a/ports/nrf/common-hal/microcontroller/__init__.c
+++ b/ports/nrf/common-hal/microcontroller/__init__.c
@@ -95,6 +95,10 @@ void common_hal_mcu_reset(void) {
     reset_cpu();
 }
 
+void common_hal_mcu_deep_sleep(void) {
+    //deep sleep call here
+}
+
 // The singleton microcontroller.Processor object, bound to microcontroller.cpu
 // It currently only has properties, and no state.
 const mcu_processor_obj_t common_hal_mcu_processor_obj = {
diff --git a/ports/stm/common-hal/microcontroller/__init__.c b/ports/stm/common-hal/microcontroller/__init__.c
index a827399ccb..bc81b0e4f5 100644
--- a/ports/stm/common-hal/microcontroller/__init__.c
+++ b/ports/stm/common-hal/microcontroller/__init__.c
@@ -81,6 +81,10 @@ void common_hal_mcu_reset(void) {
     NVIC_SystemReset();
 }
 
+void common_hal_mcu_deep_sleep(void) {
+    //deep sleep call here
+}
+
 // The singleton microcontroller.Processor object, bound to microcontroller.cpu
 // It currently only has properties, and no state.
 const mcu_processor_obj_t common_hal_mcu_processor_obj = {
diff --git a/py/circuitpy_defns.mk b/py/circuitpy_defns.mk
index ccdf973e9f..d6c0f995ec 100644
--- a/py/circuitpy_defns.mk
+++ b/py/circuitpy_defns.mk
@@ -99,6 +99,18 @@ endif
 ifeq ($(CIRCUITPY_AESIO),1)
 SRC_PATTERNS += aesio/%
 endif
+ifeq ($(CIRCUITPY_ALARM),1)
+SRC_PATTERNS += alarm/%
+endif
+ifeq ($(CIRCUITPY_ALARM_IO),1)
+SRC_PATTERNS += alarm_io/%
+endif
+ifeq ($(CIRCUITPY_ALARM_TIME),1)
+SRC_PATTERNS += alarm_time/%
+endif
+ifeq ($(CIRCUITPY_ALARM_TOUCH),1)
+SRC_PATTERNS += alarm_touch/%
+endif
 ifeq ($(CIRCUITPY_ANALOGIO),1)
 SRC_PATTERNS += analogio/%
 endif
@@ -235,6 +247,9 @@ endif
 ifeq ($(CIRCUITPY_SHARPDISPLAY),1)
 SRC_PATTERNS += sharpdisplay/%
 endif
+ifeq ($(CIRCUITPY_SLEEP),1)
+SRC_PATTERNS += sleep/%
+endif
 ifeq ($(CIRCUITPY_SOCKETPOOL),1)
 SRC_PATTERNS += socketpool/%
 endif
@@ -298,6 +313,10 @@ SRC_COMMON_HAL_ALL = \
 	_bleio/__init__.c \
 	_pew/PewPew.c \
 	_pew/__init__.c \
+	alarm/__init__.c \
+	alarm_io/__init__.c \
+	alarm_time/__init__.c \
+	alarm_touch/__init__.c \
 	analogio/AnalogIn.c \
 	analogio/AnalogOut.c \
 	analogio/__init__.c \
@@ -353,6 +372,8 @@ SRC_COMMON_HAL_ALL = \
 	rtc/__init__.c \
 	sdioio/SDCard.c \
 	sdioio/__init__.c \
+	sleep/__init__.c \
+	sleep/ResetReason.c \
 	socketpool/__init__.c \
 	socketpool/SocketPool.c \
 	socketpool/Socket.c \
diff --git a/py/circuitpy_mpconfig.h b/py/circuitpy_mpconfig.h
index 08efabddb5..11f8448927 100644
--- a/py/circuitpy_mpconfig.h
+++ b/py/circuitpy_mpconfig.h
@@ -243,6 +243,34 @@ extern const struct _mp_obj_module_t aesio_module;
 #define AESIO_MODULE
 #endif
 
+#if CIRCUITPY_ALARM
+extern const struct _mp_obj_module_t alarm_module;
+#define ALARM_MODULE           { MP_OBJ_NEW_QSTR(MP_QSTR_alarm), (mp_obj_t)&alarm_module },
+#else
+#define ALARM_MODULE
+#endif
+
+#if CIRCUITPY_ALARM_IO
+extern const struct _mp_obj_module_t alarm_io_module;
+#define ALARM_IO_MODULE        { MP_OBJ_NEW_QSTR(MP_QSTR_alarm_io), (mp_obj_t)&alarm_io_module },
+#else
+#define ALARM_IO_MODULE
+#endif
+
+#if CIRCUITPY_ALARM_TIME
+extern const struct _mp_obj_module_t alarm_time_module;
+#define ALARM_TIME_MODULE      { MP_OBJ_NEW_QSTR(MP_QSTR_alarm_time), (mp_obj_t)&alarm_time_module },
+#else
+#define ALARM_TIME_MODULE
+#endif
+
+#if CIRCUITPY_ALARM_TOUCH
+extern const struct _mp_obj_module_t alarm_touch_module;
+#define ALARM_TOUCH_MODULE      { MP_OBJ_NEW_QSTR(MP_QSTR_alarm_touch), (mp_obj_t)&alarm_touch_module },
+#else
+#define ALARM_TOUCH_MODULE
+#endif
+
 #if CIRCUITPY_ANALOGIO
 #define ANALOGIO_MODULE        { MP_OBJ_NEW_QSTR(MP_QSTR_analogio), (mp_obj_t)&analogio_module },
 extern const struct _mp_obj_module_t analogio_module;
@@ -607,7 +635,6 @@ extern const struct _mp_obj_module_t sdioio_module;
 #define SDIOIO_MODULE
 #endif
 
-
 #if CIRCUITPY_SHARPDISPLAY
 extern const struct _mp_obj_module_t sharpdisplay_module;
 #define SHARPDISPLAY_MODULE        { MP_OBJ_NEW_QSTR(MP_QSTR_sharpdisplay),(mp_obj_t)&sharpdisplay_module },
@@ -615,6 +642,13 @@ extern const struct _mp_obj_module_t sharpdisplay_module;
 #define SHARPDISPLAY_MODULE
 #endif
 
+#if CIRCUITPY_SLEEP
+extern const struct _mp_obj_module_t sleep_module;
+#define SLEEP_MODULE        { MP_OBJ_NEW_QSTR(MP_QSTR_sleep),(mp_obj_t)&sleep_module },
+#else
+#define SLEEP_MODULE
+#endif
+
 #if CIRCUITPY_SOCKETPOOL
 extern const struct _mp_obj_module_t socketpool_module;
 #define SOCKETPOOL_MODULE           { MP_OBJ_NEW_QSTR(MP_QSTR_socketpool), (mp_obj_t)&socketpool_module },
@@ -772,6 +806,10 @@ extern const struct _mp_obj_module_t wifi_module;
 // Some are omitted because they're in MICROPY_PORT_BUILTIN_MODULE_WEAK_LINKS above.
 #define MICROPY_PORT_BUILTIN_MODULES_STRONG_LINKS \
     AESIO_MODULE \
+    ALARM_MODULE \
+    ALARM_IO_MODULE \
+    ALARM_TIME_MODULE \
+    ALARM_TOUCH_MODULE \
     ANALOGIO_MODULE \
     AUDIOBUSIO_MODULE \
     AUDIOCORE_MODULE \
@@ -824,6 +862,7 @@ extern const struct _mp_obj_module_t wifi_module;
     SDCARDIO_MODULE \
     SDIOIO_MODULE \
     SHARPDISPLAY_MODULE \
+    SLEEP_MODULE \
     SOCKETPOOL_MODULE \
     SSL_MODULE \
     STAGE_MODULE \
diff --git a/py/circuitpy_mpconfig.mk b/py/circuitpy_mpconfig.mk
index a6aabec33d..c47e3755ba 100644
--- a/py/circuitpy_mpconfig.mk
+++ b/py/circuitpy_mpconfig.mk
@@ -39,6 +39,18 @@ CFLAGS += -DMICROPY_PY_ASYNC_AWAIT=$(MICROPY_PY_ASYNC_AWAIT)
 CIRCUITPY_AESIO ?= 0
 CFLAGS += -DCIRCUITPY_AESIO=$(CIRCUITPY_AESIO)
 
+CIRCUITPY_ALARM ?= 0
+CFLAGS += -DCIRCUITPY_ALARM=$(CIRCUITPY_ALARM)
+
+CIRCUITPY_ALARM_IO ?= 0
+CFLAGS += -DCIRCUITPY_ALARM_IO=$(CIRCUITPY_ALARM_IO)
+
+CIRCUITPY_ALARM_TIME ?= 0
+CFLAGS += -DCIRCUITPY_ALARM_TIME=$(CIRCUITPY_ALARM_TIME)
+
+CIRCUITPY_ALARM_TOUCH ?= 0
+CFLAGS += -DCIRCUITPY_ALARM_TOUCH=$(CIRCUITPY_ALARM_TOUCH)
+
 CIRCUITPY_ANALOGIO ?= 1
 CFLAGS += -DCIRCUITPY_ANALOGIO=$(CIRCUITPY_ANALOGIO)
 
@@ -209,6 +221,11 @@ CFLAGS += -DCIRCUITPY_SDIOIO=$(CIRCUITPY_SDIOIO)
 CIRCUITPY_SHARPDISPLAY ?= $(CIRCUITPY_FRAMEBUFFERIO)
 CFLAGS += -DCIRCUITPY_SHARPDISPLAY=$(CIRCUITPY_SHARPDISPLAY)
 
+# TODO: CIRCUITPY_SLEEP will gradually be added to all ports
+# even if it doesn't actually sleep, so make this 1 eventually.
+CIRCUITPY_SLEEP ?= 0
+CFLAGS += -DCIRCUITPY_SLEEP=$(CIRCUITPY_SLEEP)
+
 CIRCUITPY_SOCKETPOOL ?= $(CIRCUITPY_WIFI)
 CFLAGS += -DCIRCUITPY_SOCKETPOOL=$(CIRCUITPY_SOCKETPOOL)
 
diff --git a/shared-bindings/_typing/__init__.pyi b/shared-bindings/_typing/__init__.pyi
index 48e68a8d57..3b3f18cb9b 100644
--- a/shared-bindings/_typing/__init__.pyi
+++ b/shared-bindings/_typing/__init__.pyi
@@ -52,3 +52,15 @@ FrameBuffer = Union[rgbmatrix.RGBMatrix]
 
   - `rgbmatrix.RGBMatrix`
 """
+
+Alarm = Union[
+    alarm_time.Time, alarm_pin.PinLevel, alarm_touch.PinTouch
+]
+"""Classes that implement the audiosample protocol
+
+  - `alarm_time.Time`
+  - `alarm_pin.PinLevel`
+  - `alarm_touch.PinTouch`
+
+  You can play use these alarms to wake from light or deep sleep.
+"""
diff --git a/shared-bindings/alarm_io/__init__.c b/shared-bindings/alarm_io/__init__.c
new file mode 100644
index 0000000000..4e42f9a2e1
--- /dev/null
+++ b/shared-bindings/alarm_io/__init__.c
@@ -0,0 +1,53 @@
+#include "py/obj.h"
+
+#include "shared-bindings/alarm_io/__init__.h"
+#include "shared-bindings/microcontroller/Pin.h"
+
+//| """alarm_io module
+//|
+//| The `alarm_io` module implements deep sleep."""
+
+STATIC mp_obj_t alarm_io_pin_state(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    enum { ARG_level, ARG_pull };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_level, MP_ARG_INT | MP_ARG_KW_ONLY | MP_ARG_REQUIRED },
+        { MP_QSTR_pull, MP_ARG_INT | MP_ARG_KW_ONLY, {.u_bool = false} },
+    };
+
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    mcu_pin_obj_t *pin = validate_obj_is_pin(pos_args[0]);
+    alarm_io_obj_t *self = m_new_obj(alarm_io_obj_t);
+
+    self->base.type = &alarm_io_type;
+    self->gpio = pin->number;
+    self->level = args[ARG_level].u_int;
+    self->pull = args[ARG_pull].u_bool;
+
+    return common_hal_alarm_io_pin_state(self);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_KW(alarm_io_pin_state_obj, 1, alarm_io_pin_state);
+
+STATIC mp_obj_t alarm_io_disable(void) {
+    common_hal_alarm_io_disable();
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_0(alarm_io_disable_obj, alarm_io_disable);
+
+STATIC const mp_rom_map_elem_t alarm_io_module_globals_table[] = {
+    { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_alarm_io) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_PinState), MP_ROM_PTR(&alarm_io_pin_state_obj) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_Disable), MP_ROM_PTR(&alarm_io_disable_obj) },
+};
+STATIC MP_DEFINE_CONST_DICT(alarm_io_module_globals, alarm_io_module_globals_table);
+
+const mp_obj_module_t alarm_io_module = {
+    .base = { &mp_type_module },
+    .globals = (mp_obj_dict_t*)&alarm_io_module_globals,
+};
+
+const mp_obj_type_t alarm_io_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_ioAlarm,
+};
diff --git a/shared-bindings/alarm_io/__init__.h b/shared-bindings/alarm_io/__init__.h
new file mode 100644
index 0000000000..0a53497c01
--- /dev/null
+++ b/shared-bindings/alarm_io/__init__.h
@@ -0,0 +1,17 @@
+#ifndef MICROPY_INCLUDED_SHARED_BINDINGS_ALARM_IO___INIT___H
+#define MICROPY_INCLUDED_SHARED_BINDINGS_ALARM_IO___INIT___H
+
+#include "py/runtime.h"
+
+typedef struct {
+    mp_obj_base_t base;
+    uint8_t gpio, level;
+    bool pull;
+} alarm_io_obj_t;
+
+extern const mp_obj_type_t alarm_io_type;
+
+extern mp_obj_t common_hal_alarm_io_pin_state (alarm_io_obj_t *self_in);
+extern void common_hal_alarm_io_disable (void);
+
+#endif //MICROPY_INCLUDED_SHARED_BINDINGS_ALARM_IO___INIT___H
diff --git a/shared-bindings/alarm_time/Time.c b/shared-bindings/alarm_time/Time.c
new file mode 100644
index 0000000000..904bf522e2
--- /dev/null
+++ b/shared-bindings/alarm_time/Time.c
@@ -0,0 +1,76 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Scott Shawcroft
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/obj.h"
+#include "shared-bindings/alarm_time/__init__.h"
+
+//| """alarm_time module
+//|
+//| The `alarm_time` module implements deep sleep."""
+
+STATIC mp_obj_t alarm_time_duration(mp_obj_t seconds_o) {
+    #if MICROPY_PY_BUILTINS_FLOAT
+    mp_float_t seconds = mp_obj_get_float(seconds_o);
+    mp_float_t msecs = 1000.0f * seconds + 0.5f;
+    #else
+    mp_int_t seconds = mp_obj_get_int(seconds_o);
+    mp_int_t msecs = 1000 * seconds;
+    #endif
+
+    if (seconds < 0) {
+        mp_raise_ValueError(translate("sleep length must be non-negative"));
+    }
+    common_hal_alarm_time_duration(msecs);
+
+    alarm_time_obj_t *self = m_new_obj(alarm_time_obj_t);
+    self->base.type = &alarm_time_type;
+
+    return self;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(alarm_time_duration_obj, alarm_time_duration);
+
+STATIC mp_obj_t alarm_time_disable(void) {
+    common_hal_alarm_time_disable();
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_0(alarm_time_disable_obj, alarm_time_disable);
+
+STATIC const mp_rom_map_elem_t alarm_time_module_globals_table[] = {
+    { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_alarm_time) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_Duration), MP_ROM_PTR(&alarm_time_duration_obj) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_Disable), MP_ROM_PTR(&alarm_time_disable_obj) },
+};
+STATIC MP_DEFINE_CONST_DICT(alarm_time_module_globals, alarm_time_module_globals_table);
+
+const mp_obj_module_t alarm_time_module = {
+    .base = { &mp_type_module },
+    .globals = (mp_obj_dict_t*)&alarm_time_module_globals,
+};
+
+const mp_obj_type_t alarm_time_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_timeAlarm,
+};
diff --git a/shared-bindings/alarm_time/Time.h b/shared-bindings/alarm_time/Time.h
new file mode 100644
index 0000000000..9962c26f25
--- /dev/null
+++ b/shared-bindings/alarm_time/Time.h
@@ -0,0 +1,42 @@
+/*
+ * This file is part of the Micro Python project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef MICROPY_INCLUDED_SHARED_BINDINGS_ALARM_TIME_TIME_H
+#define MICROPY_INCLUDED_SHARED_BINDINGS_ALARM_TIME_TIME_H
+
+#include "py/runtime.h"
+
+typedef struct {
+    mp_obj_base_t base;
+    uint64_t time_to_alarm;
+} alarm_time_time_obj_t;
+
+extern const mp_obj_type_t alarm_time_time_type;
+
+void common_hal_alarm_time_time_construct(alarm_time_time_obj_t* self,
+                                          uint64_t ticks_ms);
+
+#endif //MICROPY_INCLUDED_SHARED_BINDINGS_ALARM_TIME_TIME_H
diff --git a/shared-bindings/alarm_time/__init__.c b/shared-bindings/alarm_time/__init__.c
new file mode 100644
index 0000000000..904bf522e2
--- /dev/null
+++ b/shared-bindings/alarm_time/__init__.c
@@ -0,0 +1,76 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Scott Shawcroft
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/obj.h"
+#include "shared-bindings/alarm_time/__init__.h"
+
+//| """alarm_time module
+//|
+//| The `alarm_time` module implements deep sleep."""
+
+STATIC mp_obj_t alarm_time_duration(mp_obj_t seconds_o) {
+    #if MICROPY_PY_BUILTINS_FLOAT
+    mp_float_t seconds = mp_obj_get_float(seconds_o);
+    mp_float_t msecs = 1000.0f * seconds + 0.5f;
+    #else
+    mp_int_t seconds = mp_obj_get_int(seconds_o);
+    mp_int_t msecs = 1000 * seconds;
+    #endif
+
+    if (seconds < 0) {
+        mp_raise_ValueError(translate("sleep length must be non-negative"));
+    }
+    common_hal_alarm_time_duration(msecs);
+
+    alarm_time_obj_t *self = m_new_obj(alarm_time_obj_t);
+    self->base.type = &alarm_time_type;
+
+    return self;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(alarm_time_duration_obj, alarm_time_duration);
+
+STATIC mp_obj_t alarm_time_disable(void) {
+    common_hal_alarm_time_disable();
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_0(alarm_time_disable_obj, alarm_time_disable);
+
+STATIC const mp_rom_map_elem_t alarm_time_module_globals_table[] = {
+    { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_alarm_time) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_Duration), MP_ROM_PTR(&alarm_time_duration_obj) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_Disable), MP_ROM_PTR(&alarm_time_disable_obj) },
+};
+STATIC MP_DEFINE_CONST_DICT(alarm_time_module_globals, alarm_time_module_globals_table);
+
+const mp_obj_module_t alarm_time_module = {
+    .base = { &mp_type_module },
+    .globals = (mp_obj_dict_t*)&alarm_time_module_globals,
+};
+
+const mp_obj_type_t alarm_time_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_timeAlarm,
+};
diff --git a/shared-bindings/alarm_time/__init__.h b/shared-bindings/alarm_time/__init__.h
new file mode 100644
index 0000000000..a963830693
--- /dev/null
+++ b/shared-bindings/alarm_time/__init__.h
@@ -0,0 +1,15 @@
+#ifndef MICROPY_INCLUDED_SHARED_BINDINGS_ALARM_TIME___INIT___H
+#define MICROPY_INCLUDED_SHARED_BINDINGS_ALARM_TIME___INIT___H
+
+#include "py/runtime.h"
+
+typedef struct {
+    mp_obj_base_t base;
+} alarm_time_obj_t;
+
+extern const mp_obj_type_t alarm_time_type;
+
+extern void common_hal_alarm_time_duration (uint32_t);
+extern void common_hal_alarm_time_disable (void);
+
+#endif //MICROPY_INCLUDED_SHARED_BINDINGS_ALARM_TIME___INIT___H
diff --git a/shared-bindings/canio/BusState.c b/shared-bindings/canio/BusState.c
new file mode 100644
index 0000000000..e0501b8d83
--- /dev/null
+++ b/shared-bindings/canio/BusState.c
@@ -0,0 +1,70 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/enum.h"
+
+#include "shared-bindings/canio/BusState.h"
+
+MAKE_ENUM_VALUE(canio_bus_state_type, bus_state, ERROR_ACTIVE, BUS_STATE_ERROR_ACTIVE);
+MAKE_ENUM_VALUE(canio_bus_state_type, bus_state, ERROR_PASSIVE, BUS_STATE_ERROR_PASSIVE);
+MAKE_ENUM_VALUE(canio_bus_state_type, bus_state, ERROR_WARNING, BUS_STATE_ERROR_WARNING);
+MAKE_ENUM_VALUE(canio_bus_state_type, bus_state, BUS_OFF, BUS_STATE_OFF);
+
+//| class BusState:
+//|     """The state of the CAN bus"""
+//|
+//|     ERROR_ACTIVE: object
+//|     """The bus is in the normal (active) state"""
+//|
+//|     ERROR_WARNING: object
+//|     """The bus is in the normal (active) state, but a moderate number of errors have occurred recently.
+//|
+//|     NOTE: Not all implementations may use ERROR_WARNING.  Do not rely on seeing ERROR_WARNING before ERROR_PASSIVE."""
+//|
+//|     ERROR_PASSIVE: object
+//|     """The bus is in the passive state due to the number of errors that have occurred recently.
+//|
+//|     This device will acknowledge packets it receives, but cannot transmit messages.
+//|     If additional errors occur, this device may progress to BUS_OFF.
+//|     If it successfully acknowledges other packets on the bus, it can return to ERROR_WARNING or ERROR_ACTIVE and transmit packets.
+//|     """
+//|
+//|     BUS_OFF: object
+//|     """The bus has turned off due to the number of errors that have
+//|     occurred recently.  It must be restarted before it will send or receive
+//|     packets.  This device will neither send or acknowledge packets on the bus."""
+//|
+MAKE_ENUM_MAP(canio_bus_state) {
+    MAKE_ENUM_MAP_ENTRY(bus_state, ERROR_ACTIVE),
+    MAKE_ENUM_MAP_ENTRY(bus_state, ERROR_PASSIVE),
+    MAKE_ENUM_MAP_ENTRY(bus_state, ERROR_WARNING),
+    MAKE_ENUM_MAP_ENTRY(bus_state, BUS_OFF),
+};
+STATIC MP_DEFINE_CONST_DICT(canio_bus_state_locals_dict, canio_bus_state_locals_table);
+
+MAKE_PRINTER(canio, canio_bus_state);
+
+MAKE_ENUM_TYPE(canio, BusState, canio_bus_state);
diff --git a/shared-bindings/canio/BusState.h b/shared-bindings/canio/BusState.h
new file mode 100644
index 0000000000..e24eba92c1
--- /dev/null
+++ b/shared-bindings/canio/BusState.h
@@ -0,0 +1,33 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Jeff Epler for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+typedef enum {
+    BUS_STATE_ERROR_ACTIVE, BUS_STATE_ERROR_PASSIVE, BUS_STATE_ERROR_WARNING, BUS_STATE_OFF
+} canio_bus_state_t;
+
+extern const mp_obj_type_t canio_bus_state_type;
diff --git a/shared-bindings/canio/__init__.c b/shared-bindings/canio/__init__.c
index f29d3ab8ac..451a68c9eb 100644
--- a/shared-bindings/canio/__init__.c
+++ b/shared-bindings/canio/__init__.c
@@ -24,6 +24,16 @@
  * THE SOFTWARE.
  */
 
+#include "py/obj.h"
+
+#include "shared-bindings/canio/__init__.h"
+
+#include "shared-bindings/canio/BusState.h"
+#include "shared-bindings/canio/CAN.h"
+#include "shared-bindings/canio/Match.h"
+#include "shared-bindings/canio/Message.h"
+#include "shared-bindings/canio/Listener.h"
+
 //| """CAN bus access
 //|
 //| The `canio` module contains low level classes to support the CAN bus
@@ -57,56 +67,6 @@
 //| """
 //|
 
-#include "py/obj.h"
-#include "py/enum.h"
-
-#include "shared-bindings/canio/__init__.h"
-#include "shared-bindings/canio/CAN.h"
-#include "shared-bindings/canio/Match.h"
-#include "shared-bindings/canio/Message.h"
-#include "shared-bindings/canio/Listener.h"
-
-MAKE_ENUM_VALUE(canio_bus_state_type, bus_state, ERROR_ACTIVE, BUS_STATE_ERROR_ACTIVE);
-MAKE_ENUM_VALUE(canio_bus_state_type, bus_state, ERROR_PASSIVE, BUS_STATE_ERROR_PASSIVE);
-MAKE_ENUM_VALUE(canio_bus_state_type, bus_state, ERROR_WARNING, BUS_STATE_ERROR_WARNING);
-MAKE_ENUM_VALUE(canio_bus_state_type, bus_state, BUS_OFF, BUS_STATE_OFF);
-
-//| class BusState:
-//|     """The state of the CAN bus"""
-//|
-//|     ERROR_ACTIVE: object
-//|     """The bus is in the normal (active) state"""
-//|
-//|     ERROR_WARNING: object
-//|     """The bus is in the normal (active) state, but a moderate number of errors have occurred recently.
-//|
-//|     NOTE: Not all implementations may use ERROR_WARNING.  Do not rely on seeing ERROR_WARNING before ERROR_PASSIVE."""
-//|
-//|     ERROR_PASSIVE: object
-//|     """The bus is in the passive state due to the number of errors that have occurred recently.
-//|
-//|     This device will acknowledge packets it receives, but cannot transmit messages.
-//|     If additional errors occur, this device may progress to BUS_OFF.
-//|     If it successfully acknowledges other packets on the bus, it can return to ERROR_WARNING or ERROR_ACTIVE and transmit packets.
-//|     """
-//|
-//|     BUS_OFF: object
-//|     """The bus has turned off due to the number of errors that have
-//|     occurred recently.  It must be restarted before it will send or receive
-//|     packets.  This device will neither send or acknowledge packets on the bus."""
-//|
-MAKE_ENUM_MAP(canio_bus_state) {
-    MAKE_ENUM_MAP_ENTRY(bus_state, ERROR_ACTIVE),
-    MAKE_ENUM_MAP_ENTRY(bus_state, ERROR_PASSIVE),
-    MAKE_ENUM_MAP_ENTRY(bus_state, ERROR_WARNING),
-    MAKE_ENUM_MAP_ENTRY(bus_state, BUS_OFF),
-};
-STATIC MP_DEFINE_CONST_DICT(canio_bus_state_locals_dict, canio_bus_state_locals_table);
-
-MAKE_PRINTER(canio, canio_bus_state);
-
-MAKE_ENUM_TYPE(canio, BusState, canio_bus_state);
-
 STATIC const mp_rom_map_elem_t canio_module_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_BusState), MP_ROM_PTR(&canio_bus_state_type) },
     { MP_ROM_QSTR(MP_QSTR_CAN), MP_ROM_PTR(&canio_can_type) },
diff --git a/shared-bindings/canio/__init__.h b/shared-bindings/canio/__init__.h
index e24eba92c1..20b6638cd8 100644
--- a/shared-bindings/canio/__init__.h
+++ b/shared-bindings/canio/__init__.h
@@ -25,9 +25,3 @@
  */
 
 #pragma once
-
-typedef enum {
-    BUS_STATE_ERROR_ACTIVE, BUS_STATE_ERROR_PASSIVE, BUS_STATE_ERROR_WARNING, BUS_STATE_OFF
-} canio_bus_state_t;
-
-extern const mp_obj_type_t canio_bus_state_type;
diff --git a/shared-bindings/microcontroller/__init__.c b/shared-bindings/microcontroller/__init__.c
index 2e58bdcc29..bbc1640f76 100644
--- a/shared-bindings/microcontroller/__init__.c
+++ b/shared-bindings/microcontroller/__init__.c
@@ -39,7 +39,6 @@
 #include "shared-bindings/microcontroller/Pin.h"
 #include "shared-bindings/microcontroller/Processor.h"
 
-#include "py/runtime.h"
 #include "supervisor/shared/translate.h"
 
 //| """Pin references and cpu functionality
@@ -136,6 +135,13 @@ STATIC mp_obj_t mcu_reset(void) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_0(mcu_reset_obj, mcu_reset);
 
+STATIC mp_obj_t mcu_sleep(void) {
+    common_hal_mcu_deep_sleep();
+    // We won't actually get here because mcu is going into sleep.
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_0(mcu_sleep_obj, mcu_sleep);
+
 //| nvm: Optional[ByteArray]
 //| """Available non-volatile memory.
 //| This object is the sole instance of `nvm.ByteArray` when available or ``None`` otherwise.
@@ -171,6 +177,8 @@ STATIC const mp_rom_map_elem_t mcu_module_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_enable_interrupts), MP_ROM_PTR(&mcu_enable_interrupts_obj) },
     { MP_ROM_QSTR(MP_QSTR_on_next_reset), MP_ROM_PTR(&mcu_on_next_reset_obj) },
     { MP_ROM_QSTR(MP_QSTR_reset), MP_ROM_PTR(&mcu_reset_obj) },
+    //ToDo: Remove MP_QSTR_sleep when sleep on code.py exit implemented.
+    { MP_ROM_QSTR(MP_QSTR_sleep), MP_ROM_PTR(&mcu_sleep_obj) },
     #if CIRCUITPY_INTERNAL_NVM_SIZE > 0
     { MP_ROM_QSTR(MP_QSTR_nvm),  MP_ROM_PTR(&common_hal_mcu_nvm_obj) },
     #else
diff --git a/shared-bindings/microcontroller/__init__.h b/shared-bindings/microcontroller/__init__.h
index 8abdff763c..f5bcfaa08a 100644
--- a/shared-bindings/microcontroller/__init__.h
+++ b/shared-bindings/microcontroller/__init__.h
@@ -28,8 +28,8 @@
 #ifndef MICROPY_INCLUDED_SHARED_BINDINGS_MICROCONTROLLER___INIT___H
 #define MICROPY_INCLUDED_SHARED_BINDINGS_MICROCONTROLLER___INIT___H
 
-#include "py/mpconfig.h"
 #include "py/obj.h"
+#include "py/mpconfig.h"
 
 #include "common-hal/microcontroller/Processor.h"
 
@@ -43,6 +43,8 @@ extern void common_hal_mcu_enable_interrupts(void);
 extern void common_hal_mcu_on_next_reset(mcu_runmode_t runmode);
 extern void common_hal_mcu_reset(void);
 
+extern void common_hal_mcu_deep_sleep(void);
+
 extern const mp_obj_dict_t mcu_pin_globals;
 
 extern const mcu_processor_obj_t common_hal_mcu_processor_obj;
diff --git a/shared-bindings/sleep/ResetReason.c b/shared-bindings/sleep/ResetReason.c
new file mode 100644
index 0000000000..cce55a81a5
--- /dev/null
+++ b/shared-bindings/sleep/ResetReason.c
@@ -0,0 +1,61 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/enum.h"
+
+#include "shared-bindings/sleep/ResetReason.h"
+
+MAKE_ENUM_VALUE(sleep_reset_reason_type, reset_reason, POWER_VALID, RESET_REASON_POWER_VALID);
+MAKE_ENUM_VALUE(sleep_reset_reason_type, reset_reason, SOFTWARE, RESET_REASON_SOFTWARE);
+MAKE_ENUM_VALUE(sleep_reset_reason_type, reset_reason, DEEP_SLEEP_ALARM, RESET_REASON_DEEP_SLEEP_ALARM);
+MAKE_ENUM_VALUE(sleep_reset_reason_type, reset_reason, EXTERNAL, RESET_REASON_EXTERNAL);
+
+//| class ResetReason:
+//|     """The reason the chip was last reset"""
+//|
+//|     POWER_VALID: object
+//|     """The chip was reset and started once power levels were valid."""
+//|
+//|     SOFTWARE: object
+//|     """The chip was reset from software."""
+//|
+//|     DEEP_SLEEP_ALARM: object
+//|     """The chip was reset for deep sleep and started by an alarm."""
+//|
+//|     EXTERNAL: object
+//|     """The chip was reset by an external input such as a button."""
+//|
+MAKE_ENUM_MAP(sleep_reset_reason) {
+    MAKE_ENUM_MAP_ENTRY(reset_reason, POWER_VALID),
+    MAKE_ENUM_MAP_ENTRY(reset_reason, SOFTWARE),
+    MAKE_ENUM_MAP_ENTRY(reset_reason, DEEP_SLEEP_ALARM),
+    MAKE_ENUM_MAP_ENTRY(reset_reason, EXTERNAL),
+};
+STATIC MP_DEFINE_CONST_DICT(sleep_reset_reason_locals_dict, sleep_reset_reason_locals_table);
+
+MAKE_PRINTER(sleep, sleep_reset_reason);
+
+MAKE_ENUM_TYPE(sleep, ResetReason, sleep_reset_reason);
diff --git a/shared-bindings/sleep/ResetReason.h b/shared-bindings/sleep/ResetReason.h
new file mode 100644
index 0000000000..2b312bb897
--- /dev/null
+++ b/shared-bindings/sleep/ResetReason.h
@@ -0,0 +1,36 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+typedef enum {
+    RESET_REASON_POWER_APPLIED,
+    RESET_REASON_SOFTWARE,
+    RESET_REASON_DEEP_SLEEP_ALARM,
+    RESET_REASON_BUTTON,
+} sleep_reset_reason_t;
+
+extern const mp_obj_type_t sleep_reset_reason_type;
diff --git a/shared-bindings/sleep/__init__.c b/shared-bindings/sleep/__init__.c
new file mode 100644
index 0000000000..a714e00213
--- /dev/null
+++ b/shared-bindings/sleep/__init__.c
@@ -0,0 +1,112 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Scott Shawcroft
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "shared-bindings/alarm/__init__.h"
+
+//| """Light and deep sleep used to save power
+//|
+//| The `sleep` module provides sleep related functionality. There are two supported levels of
+//| sleep, light and deep.
+//|
+//| Light sleep leaves the CPU and RAM powered so that CircuitPython can resume where it left off
+//| after being woken up. Light sleep is automatically done by CircuitPython when `time.sleep()` is
+//| called. To light sleep until a non-time alarm use `sleep.sleep_until_alarm()`. Any active
+//| peripherals, such as I2C, are left on.
+//|
+//| Deep sleep shuts down power to nearly all of the chip including the CPU and RAM. This can save
+//| a more significant amount of power, but CircuitPython must start code.py from the beginning when woken
+//| up. CircuitPython will enter deep sleep automatically when the current program exits without error
+//| or calls `sys.exit(0)`.
+//| If an error causes CircuitPython to exit, error LED error flashes will be done periodically.
+//| An error includes an uncaught exception, or sys.exit called with a non-zero argumetn.
+//| To set alarms for deep sleep use `sleep.restart_on_alarm()` they will apply to next deep sleep only."""
+//|
+
+//| wake_alarm: Alarm
+//| """The most recent alarm to wake us up from a sleep (light or deep.)"""
+//|
+
+//| reset_reason: ResetReason
+//| """The reason the chip started up from reset state. This can may be power up or due to an alarm."""
+//|
+
+//| def sleep_until_alarm(alarm: Alarm, ...) -> Alarm:
+//|     """Performs a light sleep until woken by one of the alarms. The alarm that woke us up is
+//|        returned."""
+//|     ...
+//|
+
+STATIC mp_obj_t sleep_sleep_until_alarm(size_t n_args, const mp_obj_t *args) {
+}
+MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(sleep_sleep_until_alarm_obj, 1, MP_OBJ_FUN_ARGS_MAX, sleep_sleep_until_alarm);
+
+//| def restart_on_alarm(alarm: Alarm, ...) -> None:
+//|     """Set one or more alarms to wake up from a deep sleep. When awakened, ``code.py`` will restart
+//| from the beginning. The last alarm to wake us up is available as `wake_alarm`. """
+//|     ...
+//|
+STATIC mp_obj_t sleep_restart_on_alarm(size_t n_args, const mp_obj_t *args) {
+}
+MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(sleep_restart_on_alarm_obj, 1, MP_OBJ_FUN_ARGS_MAX, sleep_restart_on_alarm);
+
+
+mp_map_elem_t sleep_module_globals_table[] = {
+    { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_sleep) },
+
+    { MP_ROM_QSTR(MP_QSTR_wake_alarm), mp_const_none },
+    { MP_ROM_QSTR(MP_QSTR_reset_reason), mp_const_none },
+
+    { MP_ROM_QSTR(MP_QSTR_sleep_until_alarm), sleep_sleep_until_alarm_obj },
+    { MP_ROM_QSTR(MP_QSTR_restart_on_alarm), sleep_restart_on_alarm_obj },
+};
+STATIC MP_DEFINE_MUTABLE_DICT(sleep_module_globals, sleep_module_globals_table);
+
+// These are called from common hal code to set the current wake alarm.
+void common_hal_sleep_set_wake_alarm(mp_obj_t alarm) {
+    // Equivalent of:
+    // sleep.wake_alarm = alarm
+    mp_map_elem_t *elem =
+        mp_map_lookup(&sleep_module_globals_table, MP_ROM_QSTR(MP_QSTR_wake_alarm), MP_MAP_LOOKUP);
+    if (elem) {
+        elem->value = alarm;
+    }
+}
+
+// These are called from common hal code to set the current wake alarm.
+void common_hal_sleep_set_reset_reason(mp_obj_t reset_reason) {
+    // Equivalent of:
+    // sleep.reset_reason = reset_reason
+    mp_map_elem_t *elem =
+        mp_map_lookup(&sleep_module_globals_table, MP_ROM_QSTR(MP_QSTR_reset_reason), MP_MAP_LOOKUP);
+    if (elem) {
+        elem->value = reset_reason;
+    }
+}
+
+const mp_obj_module_t sleep_module = {
+    .base = { &mp_type_module },
+    .globals = (mp_obj_dict_t*)&sleep_module_globals,
+};
diff --git a/shared-bindings/sleep/__init__.h b/shared-bindings/sleep/__init__.h
new file mode 100644
index 0000000000..cd23ba5e49
--- /dev/null
+++ b/shared-bindings/sleep/__init__.h
@@ -0,0 +1,9 @@
+#ifndef MICROPY_INCLUDED_SHARED_BINDINGS_SLEEP___INIT___H
+#define MICROPY_INCLUDED_SHARED_BINDINGS_SLEEP___INIT___H
+
+#include "py/obj.h"
+
+extern mp_obj_t common_hal_sleep_get_wake_alarm(void);
+extern sleep_reset_reason_t common_hal_sleep_get_reset_reason(void);
+
+#endif  // MICROPY_INCLUDED_SHARED_BINDINGS_SLEEPxs___INIT___H
diff --git a/shared-bindings/supervisor/RunReason.c b/shared-bindings/supervisor/RunReason.c
new file mode 100644
index 0000000000..5233cf959b
--- /dev/null
+++ b/shared-bindings/supervisor/RunReason.c
@@ -0,0 +1,62 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/enum.h"
+
+#include "shared-bindings/supervisor/RunReason.h"
+
+MAKE_ENUM_VALUE(canio_bus_state_type, run_reason, ERROR_ACTIVE, RUN_REASON_STARTUP);
+MAKE_ENUM_VALUE(canio_bus_state_type, bus_state, ERROR_PASSIVE, RUN_REASON_AUTORELOAD);
+MAKE_ENUM_VALUE(canio_bus_state_type, bus_state, ERROR_WARNING, RUN_REASON_SUPERVISOR_RELOAD);
+MAKE_ENUM_VALUE(canio_bus_state_type, bus_state, BUS_OFF, RUN_REASON_RELOAD_HOTKEY);
+
+//| class RunReason:
+//|     """The state of the CAN bus"""
+//|
+//|     STARTUP: object
+//|     """The first VM was run after the microcontroller started up. See `microcontroller.start_reason`
+//|        for more detail why the microcontroller was started."""
+//|
+//|     AUTORELOAD: object
+//|     """The VM was run due to a USB write to the filesystem."""
+//|
+//|     SUPERVISOR_RELOAD: object
+//|     """The VM was run due to a call to `supervisor.reload()`."""
+//|
+//|     RELOAD_HOTKEY: object
+//|     """The VM was run due CTRL-D."""
+//|
+MAKE_ENUM_MAP(canio_bus_state) {
+    MAKE_ENUM_MAP_ENTRY(bus_state, ERROR_ACTIVE),
+    MAKE_ENUM_MAP_ENTRY(bus_state, ERROR_PASSIVE),
+    MAKE_ENUM_MAP_ENTRY(bus_state, ERROR_WARNING),
+    MAKE_ENUM_MAP_ENTRY(bus_state, BUS_OFF),
+};
+STATIC MP_DEFINE_CONST_DICT(canio_bus_state_locals_dict, canio_bus_state_locals_table);
+
+MAKE_PRINTER(canio, canio_bus_state);
+
+MAKE_ENUM_TYPE(canio, BusState, canio_bus_state);
diff --git a/shared-bindings/supervisor/RunReason.h b/shared-bindings/supervisor/RunReason.h
new file mode 100644
index 0000000000..f9aaacae63
--- /dev/null
+++ b/shared-bindings/supervisor/RunReason.h
@@ -0,0 +1,36 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+typedef enum {
+    RUN_REASON_STARTUP,
+    RUN_REASON_AUTORELOAD,
+    RUN_REASON_SUPERVISOR_RELOAD,
+    RUN_REASON_RELOAD_HOTKEY
+} supervisor_run_reason_t;
+
+extern const mp_obj_type_t canio_bus_state_type;
diff --git a/shared-bindings/supervisor/Runtime.c b/shared-bindings/supervisor/Runtime.c
index bfca6e7b1d..f9db38c9b5 100755
--- a/shared-bindings/supervisor/Runtime.c
+++ b/shared-bindings/supervisor/Runtime.c
@@ -90,9 +90,31 @@ const mp_obj_property_t supervisor_serial_bytes_available_obj = {
 };
 
 
+//|     run_reason: RunReason
+//|     """Returns why the Python VM was run this time."""
+//|
+STATIC mp_obj_t supervisor_get_run_reason(mp_obj_t self) {
+    if (!common_hal_get_serial_bytes_available()) {
+        return mp_const_false;
+    }
+    else {
+        return mp_const_true;
+    }
+}
+MP_DEFINE_CONST_FUN_OBJ_1(supervisor_get_run_reason_obj, supervisor_get_run_reason);
+
+const mp_obj_property_t supervisor_run_reason_obj = {
+    .base.type = &mp_type_property,
+    .proxy = {(mp_obj_t)&supervisor_get_run_reason_obj,
+              (mp_obj_t)&mp_const_none_obj,
+              (mp_obj_t)&mp_const_none_obj},
+};
+
+
 STATIC const mp_rom_map_elem_t supervisor_runtime_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_serial_connected), MP_ROM_PTR(&supervisor_serial_connected_obj) },
     { MP_ROM_QSTR(MP_QSTR_serial_bytes_available), MP_ROM_PTR(&supervisor_serial_bytes_available_obj) },
+    { MP_ROM_QSTR(MP_QSTR_run_reason), MP_ROM_PTR(&supervisor_run_reason_obj) },
 };
 
 STATIC MP_DEFINE_CONST_DICT(supervisor_runtime_locals_dict, supervisor_runtime_locals_dict_table);
diff --git a/supervisor/shared/rgb_led_status.c b/supervisor/shared/rgb_led_status.c
index 283b9da123..bff74a1f0e 100644
--- a/supervisor/shared/rgb_led_status.c
+++ b/supervisor/shared/rgb_led_status.c
@@ -367,6 +367,7 @@ void prep_rgb_status_animation(const pyexec_result_t* result,
     status->found_main = found_main;
     status->total_exception_cycle = 0;
     status->ok = result->return_code != PYEXEC_EXCEPTION;
+    status->cycles = 0;
     if (status->ok) {
         // If this isn't an exception, skip exception sorting and handling
         return;
@@ -411,14 +412,16 @@ void prep_rgb_status_animation(const pyexec_result_t* result,
     #endif
 }
 
-void tick_rgb_status_animation(rgb_status_animation_t* status) {
+bool tick_rgb_status_animation(rgb_status_animation_t* status) {
     #if defined(MICROPY_HW_NEOPIXEL) || (defined(MICROPY_HW_APA102_MOSI) && defined(MICROPY_HW_APA102_SCK)) || (defined(CP_RGB_STATUS_LED))
     uint32_t tick_diff = supervisor_ticks_ms32() - status->pattern_start;
     if (status->ok) {
         // All is good. Ramp ALL_DONE up and down.
         if (tick_diff > ALL_GOOD_CYCLE_MS) {
             status->pattern_start = supervisor_ticks_ms32();
-            tick_diff = 0;
+            status->cycles++;
+            new_status_color(BLACK);
+            return status->cycles;
         }
 
         uint16_t brightness = tick_diff * 255 / (ALL_GOOD_CYCLE_MS / 2);
@@ -433,7 +436,8 @@ void tick_rgb_status_animation(rgb_status_animation_t* status) {
     } else {
         if (tick_diff > status->total_exception_cycle) {
             status->pattern_start = supervisor_ticks_ms32();
-            tick_diff = 0;
+            status->cycles++;
+            return;
         }
         // First flash the file color.
         if (tick_diff < EXCEPTION_TYPE_LENGTH_MS) {
diff --git a/supervisor/shared/safe_mode.c b/supervisor/shared/safe_mode.c
index d59e754ed4..905a0c408f 100644
--- a/supervisor/shared/safe_mode.c
+++ b/supervisor/shared/safe_mode.c
@@ -52,6 +52,10 @@ safe_mode_t wait_for_safe_mode_reset(void) {
         current_safe_mode = safe_mode;
         return safe_mode;
     }
+    if (common_hal_sleep_get_reset_reason() != RESET_REASON_POWER_VALID &&
+        common_hal_sleep_get_reset_reason() != RESET_REASON_BUTTON) {
+        return NO_SAFE_MODE;
+    }
     port_set_saved_word(SAFE_MODE_DATA_GUARD | (MANUAL_SAFE_MODE << 8));
     // Wait for a while to allow for reset.
     temp_status_color(SAFE_MODE);
diff --git a/supervisor/shared/serial.h b/supervisor/shared/serial.h
new file mode 100644
index 0000000000..84f92c337c
--- /dev/null
+++ b/supervisor/shared/serial.h
@@ -0,0 +1,29 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+extern volatile bool _serial_connected;
diff --git a/supervisor/shared/usb/usb.c b/supervisor/shared/usb/usb.c
index 93d3436e9d..8a425c9907 100644
--- a/supervisor/shared/usb/usb.c
+++ b/supervisor/shared/usb/usb.c
@@ -105,21 +105,26 @@ void usb_irq_handler(void) {
 // Invoked when device is mounted
 void tud_mount_cb(void) {
     usb_msc_mount();
+    _workflow_active = true;
 }
 
 // Invoked when device is unmounted
 void tud_umount_cb(void) {
     usb_msc_umount();
+    _workflow_active = false;
 }
 
 // Invoked when usb bus is suspended
 // remote_wakeup_en : if host allows us to perform remote wakeup
 // USB Specs: Within 7ms, device must draw an average current less than 2.5 mA from bus
 void tud_suspend_cb(bool remote_wakeup_en) {
+    _serial_connected = false;
+    _workflow_active = false;
 }
 
 // Invoked when usb bus is resumed
 void tud_resume_cb(void) {
+    _workflow_active = true;
 }
 
 // Invoked when cdc when line state changed e.g connected/disconnected
@@ -127,6 +132,8 @@ void tud_resume_cb(void) {
 void tud_cdc_line_state_cb(uint8_t itf, bool dtr, bool rts) {
     (void) itf; // interface ID, not used
 
+    _serial_connected = dtr;
+
     // DTR = false is counted as disconnected
     if ( !dtr )
     {
diff --git a/supervisor/shared/workflow.c b/supervisor/shared/workflow.c
new file mode 100644
index 0000000000..adcffb319a
--- /dev/null
+++ b/supervisor/shared/workflow.c
@@ -0,0 +1,32 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+// Set by the shared USB code.
+volatile bool _workflow_active;
+
+bool workflow_active(void) {
+    return _workflow_active;
+}
diff --git a/supervisor/shared/workflow.h b/supervisor/shared/workflow.h
new file mode 100644
index 0000000000..4a138332a7
--- /dev/null
+++ b/supervisor/shared/workflow.h
@@ -0,0 +1,29 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+extern volatile bool _workflow_active;
diff --git a/supervisor/supervisor.mk b/supervisor/supervisor.mk
index e81c51a88c..a59e99e3de 100644
--- a/supervisor/supervisor.mk
+++ b/supervisor/supervisor.mk
@@ -75,6 +75,7 @@ else
 		lib/tinyusb/src/class/cdc/cdc_device.c \
 		lib/tinyusb/src/tusb.c \
 		supervisor/shared/serial.c \
+		supervisor/shared/workflow.c \
 		supervisor/usb.c \
 		supervisor/shared/usb/usb_desc.c \
 		supervisor/shared/usb/usb.c \
diff --git a/supervisor/workflow.h b/supervisor/workflow.h
new file mode 100755
index 0000000000..4008b83a11
--- /dev/null
+++ b/supervisor/workflow.h
@@ -0,0 +1,30 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#pragma once
+
+// True when the user could be actively iterating on their code.
+bool workflow_active(void);