diff --git a/main.c b/main.c
index a9dbb1b7c3..dda439d6de 100755
--- a/main.c
+++ b/main.c
@@ -66,9 +66,6 @@
 
 #include "boards/board.h"
 
-// REMOVE ***********
-#include "esp_log.h"
-
 #if CIRCUITPY_ALARM
 #include "shared-bindings/alarm/__init__.h"
 #endif
@@ -98,12 +95,6 @@
 #include "common-hal/canio/CAN.h"
 #endif
 
-// How long to wait for host to start connecting..
-#define CIRCUITPY_USB_CONNECTING_DELAY 1
-
-// How long to flash errors on the RGB status LED before going to sleep (secs)
-#define CIRCUITPY_FLASH_ERROR_PERIOD 10
-
 #if MICROPY_ENABLE_PYSTACK
 static size_t PLACE_IN_DTCM_BSS(_pystack[CIRCUITPY_PYSTACK_SIZE / sizeof(size_t)]);
 #endif
@@ -259,17 +250,6 @@ STATIC void print_code_py_status_message(safe_mode_t safe_mode) {
     }
 }
 
-// Should we go into deep sleep when program finishes?
-// Normally we won't deep sleep if there was an error or if we are connected to a host
-// but either of those can be enabled.
-// It's ok to deep sleep if we're not connected to a host, but we need to make sure
-// we're giving enough time for USB to start to connect
-STATIC bool deep_sleep_allowed(void) {
-    return
-        (ok || supervisor_workflow_get_allow_deep_sleep_on_error()) &&
-        !supervisor_workflow_connecting()
-        (supervisor_ticks_ms64() > CIRCUITPY_USB_CONNECTING_DELAY * 1024);
-
 STATIC bool run_code_py(safe_mode_t safe_mode) {
     bool serial_connected_at_start = serial_connected();
     #if CIRCUITPY_AUTORELOAD_DELAY_MS > 0
@@ -290,10 +270,12 @@ STATIC bool run_code_py(safe_mode_t safe_mode) {
     if (safe_mode == NO_SAFE_MODE) {
         new_status_color(MAIN_RUNNING);
 
-        static const char * const supported_filenames[] = STRING_LIST("code.txt", "code.py", "main.py", "main.txt");
+        static const char * const supported_filenames[] = STRING_LIST(
+            "code.txt", "code.py", "main.py", "main.txt");
         #if CIRCUITPY_FULL_BUILD
-        static const char * const double_extension_filenames[] = STRING_LIST("code.txt.py", "code.py.txt", "code.txt.txt","code.py.py",
-                                                    "main.txt.py", "main.py.txt", "main.txt.txt","main.py.py");
+        static const char * const double_extension_filenames[] = STRING_LIST(
+            "code.txt.py", "code.py.txt", "code.txt.txt","code.py.py",
+            "main.txt.py", "main.py.txt", "main.txt.txt","main.py.py");
         #endif
 
         stack_resize();
@@ -319,7 +301,7 @@ STATIC bool run_code_py(safe_mode_t safe_mode) {
     // Program has finished running.
 
     // Display a different completion message if the user has no USB attached (cannot save files)
-    if (!serial_connected_at_start && !deep_sleep_allowed()) {
+    if (!serial_connected_at_start) {
         serial_write_compressed(translate("\nCode done running. Waiting for reload.\n"));
     }
 
@@ -327,16 +309,8 @@ STATIC bool run_code_py(safe_mode_t safe_mode) {
     #if CIRCUITPY_DISPLAYIO
     bool refreshed_epaper_display = false;
     #endif
+
     rgb_status_animation_t animation;
-    bool ok = result.return_code != PYEXEC_EXCEPTION;
-
-    #if CIRCUITPY_ALARM
-    // Enable pin or time alarms before sleeping.
-    // If immediate_wake is true, then there's an alarm that would trigger immediately,
-    // so don't sleep.
-    bool immediate_wake = !common_hal_alarm_enable_deep_sleep_alarms();
-    #endif
-
     prep_rgb_status_animation(&result, found_main, safe_mode, &animation);
     while (true) {
 
@@ -360,12 +334,10 @@ STATIC bool run_code_py(safe_mode_t safe_mode) {
             if (!serial_connected_at_start) {
                 print_code_py_status_message(safe_mode);
             }
-            // We won't be going into the REPL if we're going to sleep.
-            if (!deep_sleep_allowed()) {
-                print_safe_mode_message(safe_mode);
-                serial_write("\n");
-                serial_write_compressed(translate("Press any key to enter the REPL. Use CTRL-D to reload."));
-            }
+
+            print_safe_mode_message(safe_mode);
+            serial_write("\n");
+            serial_write_compressed(translate("Press any key to enter the REPL. Use CTRL-D to reload."));
         }
         if (serial_connected_before_animation && !serial_connected()) {
             serial_connected_at_start = false;
@@ -379,37 +351,7 @@ STATIC bool run_code_py(safe_mode_t safe_mode) {
         }
         #endif
 
-        bool animation_done = false;
-
-        if (deep_sleep_allowed() && ok) {
-            // Skip animation if everything is OK.
-            animation_done = true;
-        } else {
-            animation_done = tick_rgb_status_animation(&animation);
-        }
-        // Do an error animation only once before deep-sleeping.
-        if (animation_done) {
-            if (immediate_wake) {
-                // Don't sleep, we are already supposed to wake up.
-                return true;
-            }
-            if (deep_sleep_allowed()) {
-                common_hal_mcu_deep_sleep();
-                // Does not return.
-            }
-
-            // Wake up every so often to flash the error code.
-            if (!ok) {
-                port_interrupt_after_ticks(CIRCUITPY_FLASH_ERROR_PERIOD * 1024);
-            } else {
-                int64_t remaining_connecting_wait =
-                    CIRCUITPY_USB_CONNECTING_DELAY * 1024 - supervisor_ticks_ms64();
-                if (remaining_connecting_wait > 0) {
-                    port_interrupt_after_ticks(remaining_connecting_wait);
-                }
-                port_sleep_until_interrupt();
-            }
-        }
+        tick_rgb_status_animation(&animation);
     }
 }
 
diff --git a/ports/atmel-samd/common-hal/microcontroller/__init__.c b/ports/atmel-samd/common-hal/microcontroller/__init__.c
index ca39f28386..50a1ec038e 100644
--- a/ports/atmel-samd/common-hal/microcontroller/__init__.c
+++ b/ports/atmel-samd/common-hal/microcontroller/__init__.c
@@ -84,10 +84,6 @@ 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 57140dec70..7aa3b839d7 100644
--- a/ports/cxd56/common-hal/microcontroller/__init__.c
+++ b/ports/cxd56/common-hal/microcontroller/__init__.c
@@ -81,10 +81,6 @@ 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
index 7cf74a0efc..767b0de70e 100644
--- a/ports/esp32s2/common-hal/alarm/__init__.c
+++ b/ports/esp32s2/common-hal/alarm/__init__.c
@@ -1,4 +1,4 @@
-/*
+ /*
  * This file is part of the MicroPython project, http://micropython.org/
  *
  * The MIT License (MIT)
@@ -77,12 +77,10 @@ mp_obj_t common_hal_alarm_get_wake_alarm(void) {
     return mp_const_none;
 }
 
-mp_obj_t common_hal_alarm_sleep_until_alarms(size_t n_alarms, const mp_obj_t *alarms) {
-    mp_raise_NotImplementedError(NULL);
-}
-
-void common_hal_alarm_set_deep_sleep_alarms(size_t n_alarms, const mp_obj_t *alarms) {
+STATIC void setup_alarms(size_t n_alarms, const mp_obj_t *alarms) {
     bool time_alarm_set = false;
+    alarm_time_time_alarm_obj_t *time_alarm = MP_OBJ_NULL;
+
     for (size_t i = 0; i < n_alarms; i++) {
         if (MP_OBJ_IS_TYPE(alarms[i], &alarm_pin_pin_alarm_type)) {
             mp_raise_NotImplementedError(translate("PinAlarm deep sleep not yet implemented"));
@@ -91,32 +89,32 @@ void common_hal_alarm_set_deep_sleep_alarms(size_t n_alarms, const mp_obj_t *ala
             if (time_alarm_set) {
                 mp_raise_ValueError(translate("Only one alarm.time alarm can be set."));
             }
+            time_alarm  = MP_OBJ_TO_PTR(alarms[i]);
             time_alarm_set = true;
         }
     }
 
-    _deep_sleep_alarms = mp_obj_new_tuple(n_alarms, alarms);
+    if (time_alarm != MP_OBJ_NULL) {
+        // Compute how long to actually sleep, considering the time now.
+        mp_float_t now_secs = uint64_to_float(common_hal_time_monotonic_ms()) / 1000.0f;
+        mp_float_t wakeup_in_secs = MAX(0.0f, time_alarm->monotonic_time - now_secs);
+        esp_sleep_enable_timer_wakeup((uint64_t) (wakeup_in_secs * 1000000));
+    }
 }
 
-// Return false if we should wake up immediately because a time alarm is in the past
-// or otherwise already triggered.
-bool common_hal_alarm_enable_deep_sleep_alarms(void) {
-    for (size_t i = 0; i < _deep_sleep_alarms->len; i++) {
-        mp_obj_t alarm = _deep_sleep_alarms->items[i];
-        if (MP_OBJ_IS_TYPE(alarm, &alarm_pin_pin_alarm_type)) {
-            // TODO: handle pin alarms
-            mp_raise_NotImplementedError(translate("PinAlarm deep sleep not yet implemented"));
-        }
-        else if (MP_OBJ_IS_TYPE(alarm, &alarm_time_time_alarm_type)) {
-            alarm_time_time_alarm_obj_t *time_alarm = MP_OBJ_TO_PTR(alarm);
-            mp_float_t now_secs = uint64_to_float(common_hal_time_monotonic_ms()) / 1000.0f;
-            // Compute how long to actually sleep, considering hte time now.
-            mp_float_t wakeup_in_secs = time_alarm->monotonic_time - now_secs;
-            if (wakeup_in_secs <= 0.0f) {
-                return false;
-            }
-            esp_sleep_enable_timer_wakeup((uint64_t) (wakeup_in_secs * 1000000));
-        }
-    }
-    return true;
+mp_obj_t common_hal_alarm_sleep_until_alarms(size_t n_alarms, const mp_obj_t *alarms) {
+    setup_alarms(n_alarms, alarms);
+
+    // Shut down wifi cleanly.
+    esp_wifi_stop();
+    esp_light_sleep_start();
+    return common_hal_alarm_get_wake_alarm();
+}
+
+void common_hal_alarm_exit_and_deep_sleep_until_alarms(size_t n_alarms, const mp_obj_t *alarms) {
+    setup_alarms(n_alarms, alarms);
+
+    // Shut down wifi cleanly.
+    esp_wifi_stop();
+    esp_deep_sleep_start();
 }
diff --git a/ports/esp32s2/common-hal/microcontroller/__init__.c b/ports/esp32s2/common-hal/microcontroller/__init__.c
index 3578b86d02..184f5be696 100644
--- a/ports/esp32s2/common-hal/microcontroller/__init__.c
+++ b/ports/esp32s2/common-hal/microcontroller/__init__.c
@@ -81,12 +81,6 @@ void common_hal_mcu_reset(void) {
     while(1);
 }
 
-void NORETURN common_hal_mcu_deep_sleep(void) {
-    // Shut down wifi cleanly.
-    esp_wifi_stop();
-    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/litex/common-hal/microcontroller/__init__.c b/ports/litex/common-hal/microcontroller/__init__.c
index e6f50ed5a6..3c91661144 100644
--- a/ports/litex/common-hal/microcontroller/__init__.c
+++ b/ports/litex/common-hal/microcontroller/__init__.c
@@ -89,10 +89,6 @@ 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 0329ced69b..6a8537e2da 100644
--- a/ports/mimxrt10xx/common-hal/microcontroller/__init__.c
+++ b/ports/mimxrt10xx/common-hal/microcontroller/__init__.c
@@ -86,10 +86,6 @@ 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 9911896bff..06aac9409d 100644
--- a/ports/nrf/common-hal/microcontroller/__init__.c
+++ b/ports/nrf/common-hal/microcontroller/__init__.c
@@ -95,10 +95,6 @@ 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 bc81b0e4f5..a827399ccb 100644
--- a/ports/stm/common-hal/microcontroller/__init__.c
+++ b/ports/stm/common-hal/microcontroller/__init__.c
@@ -81,10 +81,6 @@ 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/shared-bindings/_typing/__init__.pyi b/shared-bindings/_typing/__init__.pyi
index 02839ab477..2716936860 100644
--- a/shared-bindings/_typing/__init__.pyi
+++ b/shared-bindings/_typing/__init__.pyi
@@ -54,12 +54,12 @@ FrameBuffer = Union[rgbmatrix.RGBMatrix]
 """
 
 Alarm = Union[
-    alarm.pin.PinAlarm, alarm.time.DurationAlarm
+    alarm.pin.PinAlarm, alarm.time.TimeAlarm
 ]
 """Classes that implement alarms for sleeping and asynchronous notification.
 
   - `alarm.pin.PinAlarm`
-  - `alarm.time.DurationAlarm`
+  - `alarm.time.TimeAlarm`
 
   You can use these alarms to wake from light or deep sleep.
 """
diff --git a/shared-bindings/alarm/__init__.c b/shared-bindings/alarm/__init__.c
index 4aa6c8457d..4c2189c0d0 100644
--- a/shared-bindings/alarm/__init__.c
+++ b/shared-bindings/alarm/__init__.c
@@ -30,6 +30,15 @@
 #include "shared-bindings/alarm/__init__.h"
 #include "shared-bindings/alarm/pin/PinAlarm.h"
 #include "shared-bindings/alarm/time/TimeAlarm.h"
+#include "shared-bindings/time/__init__.h"
+#include "supervisor/shared/rgb_led_status.h"
+#include "supervisor/shared/workflow.h"
+
+// Wait this long to see if USB is being connected (enumeration starting).
+#define CIRCUITPY_USB_CONNECTING_DELAY 1
+// Wait this long before going into deep sleep if connected. This
+// allows the user to ctrl-C before deep sleep starts.
+#define CIRCUITPY_USB_CONNECTED_DEEP_SLEEP_DELAY 5
 
 //| """Power-saving light and deep sleep. Alarms can be set to wake up from sleep.
 //|
@@ -44,16 +53,12 @@
 //| 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
 //| awakened.
+//| """
 
-//|
-//| An error includes an uncaught exception, or sys.exit() called with a non-zero argument
-//|
-//| To set alarms for deep sleep use `alarm.set_deep_sleep_alarms()` 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.)"""
 //|
-
 void validate_objs_are_alarms(size_t n_args, const mp_obj_t *objs) {
     for (size_t i = 0; i < n_args; i++) {
         if (MP_OBJ_IS_TYPE(objs[i], &alarm_pin_pin_alarm_type) ||
@@ -88,12 +93,38 @@ MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(alarm_sleep_until_alarms_obj, 1, MP_OBJ_FUN_
 //|     For time-base alarms, currently, an `alarm.time.TimeAlarm()` is created.
 //|
 //|     If no alarms are specified, the microcontroller will deep sleep until reset.
+//|
+//|     If CircuitPython is unconnected to a host computer, go into deep sleep immediately.
+//|     But if it already connected or in the process of connecting to a host computer, wait at least
+//|     five seconds after starting code.py before entering deep sleep.
+//|     This allows interrupting a program that would otherwise go into deep sleep too quickly
+//|     to interrupt from the keyboard.
 //|     """
 //|     ...
 //|
 STATIC mp_obj_t alarm_exit_and_deep_sleep_until_alarms(size_t n_args, const mp_obj_t *args) {
     validate_objs_are_alarms(n_args, args);
-    common_hal_exit_and_deep_sleep_until_alarms(n_args, args);
+
+    int64_t connecting_delay_msec = CIRCUITPY_USB_CONNECTING_DELAY * 1024 - supervisor_ticks_ms64();
+    if (connecting_delay_msec > 0) {
+        common_hal_time_delay_ms(connecting_delay_msec * 1000 / 1024);
+    }
+
+    // If connected, wait for the program to be running at least as long as
+    // CIRCUITPY_USB_CONNECTED_DEEP_SLEEP_DELAY. This allows a user to ctrl-C the running
+    // program in case it is in a tight deep sleep loop that would otherwise be difficult
+    // or impossible to interrupt.
+    // Indicate that we're delaying with the SAFE_MODE color.
+    int64_t delay_before_sleeping_msec =
+        supervisor_ticks_ms64() - CIRCUITPY_USB_CONNECTED_DEEP_SLEEP_DELAY * 1000;
+    if (supervisor_workflow_connecting() && delay_before_sleeping_msec > 0) {
+        temp_status_color(SAFE_MODE);
+        common_hal_time_delay_ms(delay_before_sleeping_msec);
+        clear_temp_status();
+    }
+
+    common_hal_alarm_exit_and_deep_sleep_until_alarms(n_args, args);
+    // Does not return.
     return mp_const_none;
 }
 MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(alarm_exit_and_deep_sleep_until_alarms_obj, 1, MP_OBJ_FUN_ARGS_MAX, alarm_exit_and_deep_sleep_until_alarms);
diff --git a/shared-bindings/alarm/__init__.h b/shared-bindings/alarm/__init__.h
index 0f084c78e8..968136345c 100644
--- a/shared-bindings/alarm/__init__.h
+++ b/shared-bindings/alarm/__init__.h
@@ -32,8 +32,7 @@
 #include "common-hal/alarm/__init__.h"
 
 extern mp_obj_t common_hal_alarm_sleep_until_alarms(size_t n_alarms, const mp_obj_t *alarms);
-extern bool common_hal_alarm_enable_deep_sleep_alarms(void);
-extern void common_hal_alarm_set_deep_sleep_alarms(size_t n_alarms, const mp_obj_t *alarms);
+extern void common_hal_alarm_exit_and_deep_sleep_until_alarms(size_t n_alarms, const mp_obj_t *alarms);
 
 // Used by wake-up code.
 extern void common_hal_alarm_set_wake_alarm(mp_obj_t alarm);
diff --git a/shared-bindings/alarm/pin/PinAlarm.c b/shared-bindings/alarm/pin/PinAlarm.c
index ff7b19ca1f..fadd1b0d4a 100644
--- a/shared-bindings/alarm/pin/PinAlarm.c
+++ b/shared-bindings/alarm/pin/PinAlarm.c
@@ -41,7 +41,7 @@
 //|     def __init__(self, *pins: microcontroller.Pin, value: bool, all_same_value: bool = False, edge: bool = False, pull: bool = False) -> None:
 //|         """Create an alarm triggered by a `microcontroller.Pin` level. The alarm is not active
 //|         until it is passed to an `alarm`-enabling function, such as `alarm.sleep_until_alarms()` or
-//|         `alarm.set_deep_sleep_alarms()`.
+//|         `alarm.exit_and_deep_sleep_until_alarms()`.
 //|
 //|         :param microcontroller.Pin \*pins: The pins to monitor. On some ports, the choice of pins
 //|           may be limited due to hardware restrictions, particularly for deep-sleep alarms.
diff --git a/shared-bindings/alarm/time/TimeAlarm.c b/shared-bindings/alarm/time/TimeAlarm.c
index 864ece284e..6339b850c6 100644
--- a/shared-bindings/alarm/time/TimeAlarm.c
+++ b/shared-bindings/alarm/time/TimeAlarm.c
@@ -24,25 +24,32 @@
  * THE SOFTWARE.
  */
 
-#include "shared-bindings/board/__init__.h"
-#include "shared-bindings/microcontroller/__init__.h"
-#include "shared-bindings/alarm/time/TimeAlarm.h"
-
 #include "py/nlr.h"
 #include "py/obj.h"
 #include "py/objproperty.h"
 #include "py/runtime.h"
+
+#include "shared-bindings/time/__init__.h"
+#include "shared-bindings/alarm/time/TimeAlarm.h"
+
 #include "supervisor/shared/translate.h"
 
+#if MICROPY_LONGINT_IMPL != MICROPY_LONGINT_IMPL_NONE
+mp_obj_t MP_WEAK rtc_get_time_source_time(void) {
+    mp_raise_RuntimeError(translate("RTC is not supported on this board"));
+}
+#endif
+
 //| class TimeAlarm:
-//|     """Trigger an alarm when `time.monotonic()` reaches the given value."""
+//|     """Trigger an alarm when the specified time is reached."""
 //|
-//|     def __init__(self, monotonic_time: float) -> None:
+//|     def __init__(self, monotonic_time: Optional[Float] = None, epoch_time: Optional[int] = None) -> None:
 //|         """Create an alarm that will be triggered when `time.monotonic()` would equal
-//|         ``monotonic_time``.
+//|         ``monotonic_time``, or when `time.time()` would equal ``epoch_time``.
+//|         Only one of the two arguments can be given.
 //|         The alarm is not active until it is passed to an
 //|         `alarm`-enabling function, such as `alarm.sleep_until_alarms()` or
-//|         `alarm.set_deep_sleep_alarms()`.
+//|         `alarm.exit_and_deep_sleep_until_alarms()`.
 //|
 //|         If the given time is in the past when sleep occurs, the alarm will be triggered
 //|         immediately.
@@ -50,21 +57,64 @@
 //|         ...
 //|
 STATIC mp_obj_t alarm_time_time_alarm_make_new(const mp_obj_type_t *type,
-        mp_uint_t n_args, const mp_obj_t *args, mp_map_t *kw_args) {
-    mp_arg_check_num(n_args, kw_args, 1, 1, false);
-
+        mp_uint_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
     alarm_time_time_alarm_obj_t *self = m_new_obj(alarm_time_time_alarm_obj_t);
     self->base.type = &alarm_time_time_alarm_type;
 
-    mp_float_t secs = mp_obj_get_float(args[0]);
+    enum { ARG_monotonic_time, ARG_epoch_time };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_monotonic_time, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_none} },
+        { MP_QSTR_epoch_time, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = mp_const_none} },
+    };
 
-    common_hal_alarm_time_time_alarm_construct(self, secs);
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    bool have_monotonic = args[ARG_monotonic_time].u_obj != mp_const_none;
+    bool have_epoch = args[ARG_epoch_time].u_obj != mp_const_none;
+
+    if (!(have_monotonic ^ have_epoch)) {
+        mp_raise_ValueError(translate("Supply one of monotonic_time or epoch_time"));
+    }
+
+    mp_float_t monotonic_time = 0;   // To avoid compiler warning.
+    if (have_monotonic) {
+        monotonic_time = mp_obj_get_float(args[ARG_monotonic_time].u_obj);
+    }
+
+    mp_float_t monotonic_time_now = common_hal_time_monotonic_ms() / 1000.0;
+
+    if (have_epoch) {
+#if MICROPY_LONGINT_IMPL == MICROPY_LONGINT_IMPL_NONE
+        mp_raise_ValueError(translate("epoch_time not supported on this board"));
+#else
+        mp_uint_t epoch_time_secs = mp_obj_int_get_checked(args[ARG_epoch_time].u_obj);
+
+        timeutils_struct_time_t tm;
+        struct_time_to_tm(rtc_get_time_source_time(), &tm);
+        mp_uint_t epoch_secs_now = timeutils_seconds_since_epoch(tm.tm_year, tm.tm_mon, tm.tm_mday,
+                                                       tm.tm_hour, tm.tm_min, tm.tm_sec);
+        // How far in the future (in secs) is the requested time?
+        mp_int_t epoch_diff = epoch_time_secs - epoch_secs_now;
+        // Convert it to a future monotonic time.
+        monotonic_time = monotonic_time_now + epoch_diff;
+#endif
+    }
+
+    if (monotonic_time < monotonic_time_now) {
+        mp_raise_ValueError(translate("Time is in the past."));
+    }
+
+    common_hal_alarm_time_time_alarm_construct(self, monotonic_time);
 
     return MP_OBJ_FROM_PTR(self);
 }
 
 //|     monotonic_time: float
-//|     """The time at which to trigger, based on the `time.monotonic()` clock."""
+//|     """When this time is reached, the alarm will trigger, based on the `time.monotonic()` clock.
+//|        The time may be given as ``epoch_time`` in the constructor, but it is returned
+//|        by this property only as a `time.monotonic()` time.
+//|        """
 //|
 STATIC mp_obj_t alarm_time_time_alarm_obj_get_monotonic_time(mp_obj_t self_in) {
     alarm_time_time_alarm_obj_t *self = MP_OBJ_TO_PTR(self_in);
diff --git a/shared-bindings/microcontroller/__init__.h b/shared-bindings/microcontroller/__init__.h
index 87284fc2e5..ac71de4247 100644
--- a/shared-bindings/microcontroller/__init__.h
+++ b/shared-bindings/microcontroller/__init__.h
@@ -43,8 +43,6 @@ 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 NORETURN 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;