add circuitpython code

1 files changed, 1000 insertions, 0 deletions

diff --git a/circuitpython/main.c b/circuitpython/main.c
new file mode 100644
index 0000000..17fe816
--- /dev/null
+++ b/circuitpython/main.c
@@ -0,0 +1,1000 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2016-2017 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 <stdint.h>
+#include <string.h>
+
+#include "extmod/vfs.h"
+#include "extmod/vfs_fat.h"
+
+#include "genhdr/mpversion.h"
+#include "py/nlr.h"
+#include "py/compile.h"
+#include "py/frozenmod.h"
+#include "py/mphal.h"
+#include "py/runtime.h"
+#include "py/repl.h"
+#include "py/gc.h"
+#include "py/stackctrl.h"
+
+#include "shared/readline/readline.h"
+#include "shared/runtime/pyexec.h"
+
+#include "background.h"
+#include "mpconfigboard.h"
+#include "supervisor/background_callback.h"
+#include "supervisor/board.h"
+#include "supervisor/cpu.h"
+#include "supervisor/filesystem.h"
+#include "supervisor/memory.h"
+#include "supervisor/port.h"
+#include "supervisor/serial.h"
+#include "supervisor/shared/reload.h"
+#include "supervisor/shared/safe_mode.h"
+#include "supervisor/shared/stack.h"
+#include "supervisor/shared/status_leds.h"
+#include "supervisor/shared/tick.h"
+#include "supervisor/shared/traceback.h"
+#include "supervisor/shared/translate.h"
+#include "supervisor/shared/workflow.h"
+#include "supervisor/usb.h"
+#include "supervisor/workflow.h"
+#include "supervisor/shared/external_flash/external_flash.h"
+
+#include "shared-bindings/microcontroller/__init__.h"
+#include "shared-bindings/microcontroller/Processor.h"
+#include "shared-bindings/supervisor/Runtime.h"
+
+#if CIRCUITPY_ALARM
+#include "shared-bindings/alarm/__init__.h"
+#endif
+
+#if CIRCUITPY_ATEXIT
+#include "shared-module/atexit/__init__.h"
+#endif
+
+#if CIRCUITPY_BLEIO
+#include "shared-bindings/_bleio/__init__.h"
+#include "supervisor/shared/bluetooth/bluetooth.h"
+#endif
+
+#if CIRCUITPY_BOARD
+#include "shared-module/board/__init__.h"
+#endif
+
+#if CIRCUITPY_CANIO
+#include "common-hal/canio/CAN.h"
+#endif
+
+#if CIRCUITPY_DISPLAYIO
+#include "shared-module/displayio/__init__.h"
+#endif
+
+#if CIRCUITPY_KEYPAD
+#include "shared-module/keypad/__init__.h"
+#endif
+
+#if CIRCUITPY_MEMORYMONITOR
+#include "shared-module/memorymonitor/__init__.h"
+#endif
+
+#if CIRCUITPY_USB_HID
+#include "shared-module/usb_hid/__init__.h"
+#endif
+
+#if CIRCUITPY_WIFI
+#include "shared-bindings/wifi/__init__.h"
+#endif
+
+#if CIRCUITPY_BOOT_COUNTER
+#include "shared-bindings/nvm/ByteArray.h"
+uint8_t value_out = 0;
+#endif
+
+#if MICROPY_ENABLE_PYSTACK
+static size_t PLACE_IN_DTCM_BSS(_pystack[CIRCUITPY_PYSTACK_SIZE / sizeof(size_t)]);
+#endif
+
+static void reset_devices(void) {
+    #if CIRCUITPY_BLEIO_HCI
+    bleio_reset();
+    #endif
+}
+
+STATIC void start_mp(supervisor_allocation *heap, bool first_run) {
+    supervisor_workflow_reset();
+
+    // Stack limit should be less than real stack size, so we have a chance
+    // to recover from limit hit.  (Limit is measured in bytes.)
+    mp_stack_ctrl_init();
+
+    if (stack_get_bottom() != NULL) {
+        mp_stack_set_limit(stack_get_length() - 1024);
+    }
+
+
+    #if MICROPY_MAX_STACK_USAGE
+    // _ezero (same as _ebss) is an int, so start 4 bytes above it.
+    if (stack_get_bottom() != NULL) {
+        mp_stack_set_bottom(stack_get_bottom());
+        mp_stack_fill_with_sentinel();
+    }
+    #endif
+
+    // Sync the file systems in case any used RAM from the GC to cache. As soon
+    // as we re-init the GC all bets are off on the cache.
+    filesystem_flush();
+
+    // Clear the readline history. It references the heap we're about to destroy.
+    readline_init0();
+
+    #if MICROPY_ENABLE_PYSTACK
+    mp_pystack_init(_pystack, _pystack + (sizeof(_pystack) / sizeof(size_t)));
+    #endif
+
+    #if MICROPY_ENABLE_GC
+    gc_init(heap->ptr, heap->ptr + get_allocation_length(heap) / 4);
+    #endif
+    mp_init();
+    mp_obj_list_init((mp_obj_list_t *)mp_sys_path, 0);
+    mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR_)); // current dir (or base dir of the script)
+    mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR__slash_));
+    #if MICROPY_MODULE_FROZEN
+    mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR__dot_frozen));
+    #endif
+    mp_obj_list_append(mp_sys_path, MP_OBJ_NEW_QSTR(MP_QSTR__slash_lib));
+
+    mp_obj_list_init((mp_obj_list_t *)mp_sys_argv, 0);
+
+    #if CIRCUITPY_ALARM
+    // Record which alarm woke us up, if any. An object may be created so the heap must be functional.
+    // There is no alarm if this is not the first time code.py or the REPL has been run.
+    shared_alarm_save_wake_alarm(first_run ? common_hal_alarm_create_wake_alarm() : mp_const_none);
+    // Reset alarm module only after we retrieved the wakeup alarm.
+    alarm_reset();
+    #endif
+}
+
+STATIC void stop_mp(void) {
+    #if MICROPY_VFS
+    mp_vfs_mount_t *vfs = MP_STATE_VM(vfs_mount_table);
+
+    // Unmount all heap allocated vfs mounts.
+    while (gc_nbytes(vfs) > 0) {
+        vfs = vfs->next;
+    }
+    MP_STATE_VM(vfs_mount_table) = vfs;
+    MP_STATE_VM(vfs_cur) = vfs;
+    #endif
+
+    background_callback_reset();
+
+    #if CIRCUITPY_USB
+    usb_background();
+    #endif
+
+    gc_deinit();
+}
+
+#define STRING_LIST(...) {__VA_ARGS__, ""}
+
+// Look for the first file that exists in the list of filenames, using mp_import_stat().
+// Return its index. If no file found, return -1.
+STATIC const char *first_existing_file_in_list(const char *const *filenames) {
+    for (int i = 0; filenames[i] != (char *)""; i++) {
+        mp_import_stat_t stat = mp_import_stat(filenames[i]);
+        if (stat == MP_IMPORT_STAT_FILE) {
+            return filenames[i];
+        }
+    }
+    return NULL;
+}
+
+STATIC bool maybe_run_list(const char *const *filenames, pyexec_result_t *exec_result) {
+    const char *filename = first_existing_file_in_list(filenames);
+    if (filename == NULL) {
+        return false;
+    }
+    mp_hal_stdout_tx_str(filename);
+    serial_write_compressed(translate(" output:\n"));
+    pyexec_file(filename, exec_result);
+    #if CIRCUITPY_ATEXIT
+    shared_module_atexit_execute(exec_result);
+    #endif
+    return true;
+}
+
+STATIC void count_strn(void *data, const char *str, size_t len) {
+    *(size_t *)data += len;
+}
+
+STATIC void cleanup_after_vm(supervisor_allocation *heap, mp_obj_t exception) {
+    // Get the traceback of any exception from this run off the heap.
+    // MP_OBJ_SENTINEL means "this run does not contribute to traceback storage, don't touch it"
+    // MP_OBJ_NULL (=0) means "this run completed successfully, clear any stored traceback"
+    if (exception != MP_OBJ_SENTINEL) {
+        free_memory(prev_traceback_allocation);
+        // ReloadException is exempt from traceback printing in pyexec_file(), so treat it as "no
+        // traceback" here too.
+        if (exception && exception != MP_OBJ_FROM_PTR(&MP_STATE_VM(mp_reload_exception))) {
+            size_t traceback_len = 0;
+            mp_print_t print_count = {&traceback_len, count_strn};
+            mp_obj_print_exception(&print_count, exception);
+            prev_traceback_allocation = allocate_memory(align32_size(traceback_len + 1), false, true);
+            // Empirically, this never fails in practice - even when the heap is totally filled up
+            // with single-block-sized objects referenced by a root pointer, exiting the VM frees
+            // up several hundred bytes, sufficient for the traceback (which tends to be shortened
+            // because there wasn't memory for the full one). There may be convoluted ways of
+            // making it fail, but at this point I believe they are not worth spending code on.
+            if (prev_traceback_allocation != NULL) {
+                vstr_t vstr;
+                vstr_init_fixed_buf(&vstr, traceback_len, (char *)prev_traceback_allocation->ptr);
+                mp_print_t print = {&vstr, (mp_print_strn_t)vstr_add_strn};
+                mp_obj_print_exception(&print, exception);
+                ((char *)prev_traceback_allocation->ptr)[traceback_len] = '\0';
+            }
+        } else {
+            prev_traceback_allocation = NULL;
+        }
+    }
+
+    // Reset port-independent devices, like CIRCUITPY_BLEIO_HCI.
+    reset_devices();
+
+    #if CIRCUITPY_ATEXIT
+    atexit_reset();
+    #endif
+
+    // Turn off the display and flush the filesystem before the heap disappears.
+    #if CIRCUITPY_DISPLAYIO
+    reset_displays();
+    #endif
+
+    #if CIRCUITPY_MEMORYMONITOR
+    memorymonitor_reset();
+    #endif
+
+    // Disable user related BLE state that uses the micropython heap.
+    #if CIRCUITPY_BLEIO
+    bleio_user_reset();
+    #endif
+
+    #if CIRCUITPY_CANIO
+    common_hal_canio_reset();
+    #endif
+
+    #if CIRCUITPY_KEYPAD
+    keypad_reset();
+    #endif
+
+    // reset_board_buses() first because it may release pins from the never_reset state, so that
+    // reset_port() can reset them.
+    #if CIRCUITPY_BOARD
+    reset_board_buses();
+    #endif
+    reset_port();
+    reset_board();
+
+    // Free the heap last because other modules may reference heap memory and need to shut down.
+    filesystem_flush();
+    stop_mp();
+    free_memory(heap);
+    supervisor_move_memory();
+}
+
+STATIC void print_code_py_status_message(safe_mode_t safe_mode) {
+    if (autoreload_is_enabled()) {
+        serial_write_compressed(
+            translate("Auto-reload is on. Simply save files over USB to run them or enter REPL to disable.\n"));
+    } else {
+        serial_write_compressed(translate("Auto-reload is off.\n"));
+    }
+    if (safe_mode != NO_SAFE_MODE) {
+        serial_write_compressed(translate("Running in safe mode! Not running saved code.\n"));
+    }
+}
+
+STATIC bool run_code_py(safe_mode_t safe_mode, bool first_run, bool *simulate_reset) {
+    bool serial_connected_at_start = serial_connected();
+    bool printed_safe_mode_message = false;
+    #if CIRCUITPY_AUTORELOAD_DELAY_MS > 0
+    if (serial_connected_at_start) {
+        serial_write("\r\n");
+        print_code_py_status_message(safe_mode);
+        print_safe_mode_message(safe_mode);
+        printed_safe_mode_message = true;
+    }
+    #endif
+
+    pyexec_result_t result;
+
+    result.return_code = 0;
+    result.exception = MP_OBJ_NULL;
+    result.exception_line = 0;
+
+    bool skip_repl = false;
+    bool skip_wait = false;
+    bool found_main = false;
+    uint8_t next_code_options = 0;
+    // Collects stickiness bits that apply in the current situation.
+    uint8_t next_code_stickiness_situation = SUPERVISOR_NEXT_CODE_OPT_NEWLY_SET;
+
+    // Do the filesystem flush check before reload in case another write comes
+    // in while we're doing the flush.
+    if (safe_mode == NO_SAFE_MODE) {
+        stack_resize();
+        filesystem_flush();
+    }
+    if (safe_mode == NO_SAFE_MODE && !autoreload_pending()) {
+        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");
+        #endif
+
+        supervisor_allocation *heap = allocate_remaining_memory();
+
+        // Prepare the VM state. Includes an alarm check/reset for sleep.
+        start_mp(heap, first_run);
+
+        #if CIRCUITPY_USB
+        usb_setup_with_vm();
+        #endif
+
+        // Check if a different run file has been allocated
+        if (next_code_allocation) {
+            ((next_code_info_t *)next_code_allocation->ptr)->options &= ~SUPERVISOR_NEXT_CODE_OPT_NEWLY_SET;
+            next_code_options = ((next_code_info_t *)next_code_allocation->ptr)->options;
+            if (((next_code_info_t *)next_code_allocation->ptr)->filename[0] != '\0') {
+                const char *next_list[] = {((next_code_info_t *)next_code_allocation->ptr)->filename, ""};
+                // This is where the user's python code is actually executed:
+                found_main = maybe_run_list(next_list, &result);
+                if (!found_main) {
+                    serial_write(((next_code_info_t *)next_code_allocation->ptr)->filename);
+                    serial_write_compressed(translate(" not found.\n"));
+                }
+            }
+        }
+        // Otherwise, default to the standard list of filenames
+        if (!found_main) {
+            // This is where the user's python code is actually executed:
+            found_main = maybe_run_list(supported_filenames, &result);
+            // If that didn't work, double check the extensions
+            #if CIRCUITPY_FULL_BUILD
+            if (!found_main) {
+                found_main = maybe_run_list(double_extension_filenames, &result);
+                if (found_main) {
+                    serial_write_compressed(translate("WARNING: Your code filename has two extensions\n"));
+                }
+            }
+            #else
+            (void)found_main;
+            #endif
+        }
+
+        // Print done before resetting everything so that we get the message over
+        // BLE before it is reset and we have a delay before reconnect.
+        if ((result.return_code & PYEXEC_RELOAD) && supervisor_get_run_reason() == RUN_REASON_AUTO_RELOAD) {
+            serial_write_compressed(translate("\nCode stopped by auto-reload. Reloading soon.\n"));
+        } else {
+            serial_write_compressed(translate("\nCode done running.\n"));
+        }
+
+
+        // Finished executing python code. Cleanup includes filesystem flush and a board reset.
+        cleanup_after_vm(heap, result.exception);
+
+        // If a new next code file was set, that is a reason to keep it (obviously). Stuff this into
+        // the options because it can be treated like any other reason-for-stickiness bit. The
+        // source is different though: it comes from the options that will apply to the next run,
+        // while the rest of next_code_options is what applied to this run.
+        if (next_code_allocation != NULL &&
+            (((next_code_info_t *)next_code_allocation->ptr)->options & SUPERVISOR_NEXT_CODE_OPT_NEWLY_SET)) {
+            next_code_options |= SUPERVISOR_NEXT_CODE_OPT_NEWLY_SET;
+        }
+
+        if (result.return_code & PYEXEC_RELOAD) {
+            next_code_stickiness_situation |= SUPERVISOR_NEXT_CODE_OPT_STICKY_ON_RELOAD;
+            // Reload immediately unless the reload is due to autoreload. In that
+            // case, we wait below to see if any other writes occur.
+            if (supervisor_get_run_reason() != RUN_REASON_AUTO_RELOAD) {
+                skip_repl = true;
+                skip_wait = true;
+            }
+        } else if (result.return_code == 0) {
+            next_code_stickiness_situation |= SUPERVISOR_NEXT_CODE_OPT_STICKY_ON_SUCCESS;
+            if (next_code_options & SUPERVISOR_NEXT_CODE_OPT_RELOAD_ON_SUCCESS) {
+                skip_repl = true;
+                skip_wait = true;
+            }
+        } else {
+            next_code_stickiness_situation |= SUPERVISOR_NEXT_CODE_OPT_STICKY_ON_ERROR;
+            // Deep sleep cannot be skipped
+            // TODO: settings in deep sleep should persist, using a new sleep memory API
+            if (next_code_options & SUPERVISOR_NEXT_CODE_OPT_RELOAD_ON_ERROR
+                && !(result.return_code & PYEXEC_DEEP_SLEEP)) {
+                skip_repl = true;
+                skip_wait = true;
+            }
+        }
+        if (result.return_code & PYEXEC_FORCED_EXIT) {
+            skip_repl = false;
+            skip_wait = true;
+        }
+    }
+
+    // Program has finished running.
+    bool printed_press_any_key = false;
+    #if CIRCUITPY_DISPLAYIO
+    size_t time_to_epaper_refresh = 1;
+    #endif
+
+    // Setup LED blinks.
+    #if CIRCUITPY_STATUS_LED
+    uint32_t color;
+    uint8_t blink_count;
+    bool led_active = false;
+    #if CIRCUITPY_ALARM
+    if (result.return_code & PYEXEC_DEEP_SLEEP) {
+        color = BLACK;
+        blink_count = 0;
+    } else
+    #endif
+    if (result.return_code != PYEXEC_EXCEPTION) {
+        if (safe_mode == NO_SAFE_MODE) {
+            color = ALL_DONE;
+            blink_count = ALL_DONE_BLINKS;
+        } else {
+            color = SAFE_MODE;
+            blink_count = SAFE_MODE_BLINKS;
+        }
+    } else {
+        color = EXCEPTION;
+        blink_count = EXCEPTION_BLINKS;
+    }
+    size_t pattern_start = supervisor_ticks_ms32();
+    size_t single_blink_time = (OFF_ON_RATIO + 1) * BLINK_TIME_MS;
+    size_t blink_time = single_blink_time * blink_count;
+    size_t total_time = blink_time + LED_SLEEP_TIME_MS;
+    #endif
+
+    // This loop is waits after code completes. It waits for fake sleeps to
+    // finish, user input or autoreloads.
+    #if CIRCUITPY_ALARM
+    bool fake_sleeping = false;
+    #endif
+    while (!skip_wait) {
+        RUN_BACKGROUND_TASKS;
+
+        // If a reload was requested by the supervisor or autoreload, return.
+        if (autoreload_ready()) {
+            next_code_stickiness_situation |= SUPERVISOR_NEXT_CODE_OPT_STICKY_ON_RELOAD;
+            // Should the STICKY_ON_SUCCESS and STICKY_ON_ERROR bits be cleared in
+            // next_code_stickiness_situation? I can see arguments either way, but I'm deciding
+            // "no" for now, mainly because it's a bit less code. At this point, we have both a
+            // success or error and a reload, so let's have both of the respective options take
+            // effect (in OR combination).
+            skip_repl = true;
+            // We're kicking off the autoreload process so reset now. If any
+            // other reloads trigger after this, then we'll want another wait
+            // period.
+            autoreload_reset();
+            break;
+        }
+
+        // If interrupted by keyboard, return
+        if (serial_connected() && serial_bytes_available()) {
+            // Skip REPL if reload was requested.
+            skip_repl = serial_read() == CHAR_CTRL_D;
+            if (skip_repl) {
+                supervisor_set_run_reason(RUN_REASON_REPL_RELOAD);
+            }
+            break;
+        }
+
+        // Check for a deep sleep alarm and restart the VM. This can happen if
+        // an alarm alerts faster than our USB delay or if we pretended to deep
+        // sleep.
+        #if CIRCUITPY_ALARM
+        if (fake_sleeping && common_hal_alarm_woken_from_sleep()) {
+            serial_write_compressed(translate("Woken up by alarm.\n"));
+            supervisor_set_run_reason(RUN_REASON_STARTUP);
+            skip_repl = true;
+            break;
+        }
+        #endif
+
+        // If messages haven't been printed yet, print them
+        if (!printed_press_any_key && serial_connected() && !autoreload_pending()) {
+            if (!serial_connected_at_start) {
+                print_code_py_status_message(safe_mode);
+            }
+
+            if (!printed_safe_mode_message) {
+                print_safe_mode_message(safe_mode);
+                printed_safe_mode_message = true;
+            }
+            serial_write("\r\n");
+            serial_write_compressed(translate("Press any key to enter the REPL. Use CTRL-D to reload.\n"));
+            printed_press_any_key = true;
+        }
+        if (!serial_connected()) {
+            serial_connected_at_start = false;
+            printed_press_any_key = false;
+        }
+
+        // Sleep until our next interrupt.
+        #if CIRCUITPY_ALARM
+        if (result.return_code & PYEXEC_DEEP_SLEEP) {
+            const bool awoke_from_true_deep_sleep =
+                common_hal_mcu_processor_get_reset_reason() == RESET_REASON_DEEP_SLEEP_ALARM;
+
+            if (fake_sleeping) {
+                // This waits until a pretend deep sleep alarm occurs. They are set
+                // during common_hal_alarm_set_deep_sleep_alarms. On some platforms
+                // it may also return due to another interrupt, that's why we check
+                // for deep sleep alarms above. If it wasn't a deep sleep alarm,
+                // then we'll idle here again.
+                common_hal_alarm_pretending_deep_sleep();
+            }
+            // The first time we go into a deep sleep, make sure we have been awake long enough
+            // for USB to connect (enumeration delay), or for the BLE workflow to start.
+            // We wait CIRCUITPY_WORKFLOW_CONNECTION_SLEEP_DELAY seconds after a restart.
+            // But if we woke up from a real deep sleep, don't wait for connection. The user will need to
+            // do a hard reset to get out of the real deep sleep.
+            else if (awoke_from_true_deep_sleep ||
+                     port_get_raw_ticks(NULL) > CIRCUITPY_WORKFLOW_CONNECTION_SLEEP_DELAY * 1024) {
+                // OK to start sleeping, real or fake.
+                status_led_deinit();
+                deinit_rxtx_leds();
+                board_deinit();
+
+                // Continue with true deep sleep even if workflow is available.
+                if (awoke_from_true_deep_sleep || !supervisor_workflow_active()) {
+                    // Enter true deep sleep. When we wake up we'll be back at the
+                    // top of main(), not in this loop.
+                    common_hal_alarm_enter_deep_sleep();
+                    // Does not return.
+                } else {
+                    serial_write_compressed(
+                        translate("Pretending to deep sleep until alarm, CTRL-C or file write.\n"));
+                    fake_sleeping = true;
+                }
+            } else {
+                // Loop while checking the time. We can't idle because we don't want to override a
+                // time alarm set for the deep sleep.
+            }
+        } else
+        #endif
+        {
+            // Refresh the ePaper display if we have one. That way it'll show an error message.
+            #if CIRCUITPY_DISPLAYIO
+            if (time_to_epaper_refresh > 0) {
+                time_to_epaper_refresh = maybe_refresh_epaperdisplay();
+            }
+
+            #if !CIRCUITPY_STATUS_LED
+            port_interrupt_after_ticks(time_to_epaper_refresh);
+            #endif
+            #endif
+
+            #if CIRCUITPY_STATUS_LED
+            uint32_t tick_diff = supervisor_ticks_ms32() - pattern_start;
+
+            // By default, don't sleep.
+            size_t time_to_next_change = 0;
+            if (tick_diff < blink_time) {
+                uint32_t blink_diff = tick_diff % (single_blink_time);
+                if (blink_diff >= BLINK_TIME_MS) {
+                    if (led_active) {
+                        new_status_color(BLACK);
+                        status_led_deinit();
+                        led_active = false;
+                    }
+                    time_to_next_change = single_blink_time - blink_diff;
+                } else {
+                    if (!led_active) {
+                        status_led_init();
+                        new_status_color(color);
+                        led_active = true;
+                    }
+                    time_to_next_change = BLINK_TIME_MS - blink_diff;
+                }
+            } else if (tick_diff > total_time) {
+                pattern_start = supervisor_ticks_ms32();
+            } else {
+                if (led_active) {
+                    new_status_color(BLACK);
+                    status_led_deinit();
+                    led_active = false;
+                }
+                time_to_next_change = total_time - tick_diff;
+            }
+            #if CIRCUITPY_DISPLAYIO
+            if (time_to_epaper_refresh > 0 && time_to_next_change > 0) {
+                time_to_next_change = MIN(time_to_next_change, time_to_epaper_refresh);
+            }
+            #endif
+
+            // time_to_next_change is in ms and ticks are slightly shorter so
+            // we'll undersleep just a little. It shouldn't matter.
+            port_interrupt_after_ticks(time_to_next_change);
+            #endif
+            port_idle_until_interrupt();
+        }
+    }
+
+    // Done waiting, start the board back up.
+
+    // We delay resetting BLE until after the wait in case we're transferring
+    // more files over.
+    #if CIRCUITPY_BLEIO
+    bleio_reset();
+    #endif
+
+    // free code allocation if unused
+    if ((next_code_options & next_code_stickiness_situation) == 0) {
+        free_memory(next_code_allocation);
+        next_code_allocation = NULL;
+    }
+
+    #if CIRCUITPY_STATUS_LED
+    if (led_active) {
+        new_status_color(BLACK);
+        status_led_deinit();
+    }
+    #endif
+
+    #if CIRCUITPY_ALARM
+    if (fake_sleeping) {
+        board_init();
+        // Pretend that the next run is the first run, as if we were reset.
+        *simulate_reset = true;
+    }
+    #endif
+
+    return skip_repl;
+}
+
+vstr_t *boot_output;
+
+STATIC void __attribute__ ((noinline)) run_boot_py(safe_mode_t safe_mode) {
+    // If not in safe mode, run boot before initing USB and capture output in a file.
+
+    // There is USB setup to do even if boot.py is not actually run.
+    const bool ok_to_run = filesystem_present()
+        && safe_mode == NO_SAFE_MODE
+        && MP_STATE_VM(vfs_mount_table) != NULL;
+
+    static const char *const boot_py_filenames[] = STRING_LIST("boot.py", "boot.txt");
+
+    // Do USB setup even if boot.py is not run.
+
+    supervisor_allocation *heap = allocate_remaining_memory();
+
+    // true means this is the first set of VM's after a hard reset.
+    start_mp(heap, true);
+
+    #if CIRCUITPY_USB
+    // Set up default USB values after boot.py VM starts but before running boot.py.
+    usb_set_defaults();
+    #endif
+
+    pyexec_result_t result = {0, MP_OBJ_NULL, 0};
+
+    if (ok_to_run) {
+        #ifdef CIRCUITPY_BOOT_OUTPUT_FILE
+        vstr_t boot_text;
+        vstr_init(&boot_text, 512);
+        boot_output = &boot_text;
+        #endif
+
+        // Write version info
+        mp_printf(&mp_plat_print, "%s\nBoard ID:%s\n", MICROPY_FULL_VERSION_INFO, CIRCUITPY_BOARD_ID);
+
+        bool found_boot = maybe_run_list(boot_py_filenames, &result);
+        (void)found_boot;
+
+
+        #ifdef CIRCUITPY_BOOT_OUTPUT_FILE
+        // Get the base filesystem.
+        fs_user_mount_t *vfs = (fs_user_mount_t *)MP_STATE_VM(vfs_mount_table)->obj;
+        FATFS *fs = &vfs->fatfs;
+
+        boot_output = NULL;
+        bool write_boot_output = true;
+        FIL boot_output_file;
+        if (f_open(fs, &boot_output_file, CIRCUITPY_BOOT_OUTPUT_FILE, FA_READ) == FR_OK) {
+            char *file_contents = m_new(char, boot_text.alloc);
+            UINT chars_read;
+            if (f_read(&boot_output_file, file_contents, 1 + boot_text.len, &chars_read) == FR_OK) {
+                write_boot_output =
+                    (chars_read != boot_text.len) || (memcmp(boot_text.buf, file_contents, chars_read) != 0);
+            }
+            // no need to f_close the file
+        }
+
+        if (write_boot_output) {
+            // Wait 1 second 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(1000);
+
+            // USB isn't up, so we can write the file.
+            // operating at the oofatfs (f_open) layer means the usb concurrent write permission
+            // is not even checked!
+            f_open(fs, &boot_output_file, CIRCUITPY_BOOT_OUTPUT_FILE, FA_WRITE | FA_CREATE_ALWAYS);
+            UINT chars_written;
+            f_write(&boot_output_file, boot_text.buf, boot_text.len, &chars_written);
+            f_close(&boot_output_file);
+            filesystem_flush();
+        }
+        #endif
+    }
+
+    #if CIRCUITPY_USB
+    // Some data needs to be carried over from the USB settings in boot.py
+    // to the next VM, while the heap is still available.
+    // Its size can vary, so save it temporarily on the stack,
+    // and then when the heap goes away, copy it in into a
+    // storage_allocation.
+    size_t size = usb_boot_py_data_size();
+    uint8_t usb_boot_py_data[size];
+    usb_get_boot_py_data(usb_boot_py_data, size);
+    #endif
+
+    cleanup_after_vm(heap, result.exception);
+
+    #if CIRCUITPY_USB
+    // Now give back the data we saved from the heap going away.
+    usb_return_boot_py_data(usb_boot_py_data, size);
+    #endif
+}
+
+STATIC int run_repl(bool first_run) {
+    int exit_code = PYEXEC_FORCED_EXIT;
+    stack_resize();
+    filesystem_flush();
+    supervisor_allocation *heap = allocate_remaining_memory();
+    start_mp(heap, first_run);
+
+    #if CIRCUITPY_USB
+    usb_setup_with_vm();
+    #endif
+
+    autoreload_suspend(AUTORELOAD_SUSPEND_REPL);
+
+    // Set the status LED to the REPL color before running the REPL. For
+    // NeoPixels and DotStars this will be sticky but for PWM or single LED it
+    // won't. This simplifies pin sharing because they won't be in use when
+    // actually in the REPL.
+    #if CIRCUITPY_STATUS_LED
+    status_led_init();
+    new_status_color(REPL_RUNNING);
+    status_led_deinit();
+    #endif
+    if (pyexec_mode_kind == PYEXEC_MODE_RAW_REPL) {
+        exit_code = pyexec_raw_repl();
+    } else {
+        exit_code = pyexec_friendly_repl();
+    }
+    #if CIRCUITPY_ATEXIT
+    pyexec_result_t result;
+    shared_module_atexit_execute(&result);
+    if (result.return_code == PYEXEC_DEEP_SLEEP) {
+        exit_code = PYEXEC_DEEP_SLEEP;
+    }
+    #endif
+    cleanup_after_vm(heap, MP_OBJ_SENTINEL);
+    #if CIRCUITPY_STATUS_LED
+    status_led_init();
+    new_status_color(BLACK);
+    status_led_deinit();
+    #endif
+
+    autoreload_resume(AUTORELOAD_SUSPEND_REPL);
+    return exit_code;
+}
+
+int __attribute__((used)) main(void) {
+    // initialise the cpu and peripherals
+    safe_mode_t safe_mode = port_init();
+
+    // Turn on RX and TX LEDs if we have them.
+    init_rxtx_leds();
+
+    #if CIRCUITPY_BOOT_COUNTER
+    // Increment counter before possibly entering safe mode
+    common_hal_nvm_bytearray_get_bytes(&common_hal_mcu_nvm_obj,0,1,&value_out);
+    ++value_out;
+    common_hal_nvm_bytearray_set_bytes(&common_hal_mcu_nvm_obj,0,&value_out,1);
+    #endif
+
+    // Wait briefly to give a reset window where we'll enter safe mode after the reset.
+    if (safe_mode == NO_SAFE_MODE) {
+        safe_mode = wait_for_safe_mode_reset();
+    }
+
+    stack_init();
+
+    #if CIRCUITPY_BLEIO
+    // Early init so that a reset press can cause BLE public advertising.
+    supervisor_bluetooth_init();
+    #endif
+
+    // Start the debug serial
+    serial_early_init();
+
+    #if !INTERNAL_FLASH_FILESYSTEM
+    // Set up anything that might need to get done before we try to use SPI flash
+    // This is needed for some boards where flash relies on GPIO setup to work
+    external_flash_setup();
+    #endif
+
+    // Create a new filesystem only if we're not in a safe mode.
+    // A power brownout here could make it appear as if there's
+    // no SPI flash filesystem, and we might erase the existing one.
+
+    // Check whether CIRCUITPY is available. No need to reset to get safe mode
+    // since we haven't run user code yet.
+    if (!filesystem_init(safe_mode == NO_SAFE_MODE, false)) {
+        safe_mode = NO_CIRCUITPY;
+    }
+
+    // displays init after filesystem, since they could share the flash SPI
+    board_init();
+
+    // Reset everything and prep MicroPython to run boot.py.
+    reset_port();
+    // Port-independent devices, like CIRCUITPY_BLEIO_HCI.
+    reset_devices();
+    reset_board();
+
+    // This is first time we are running CircuitPython after a reset or power-up.
+    supervisor_set_run_reason(RUN_REASON_STARTUP);
+
+    // If not in safe mode turn on autoreload by default but before boot.py in case it wants to change it.
+    if (safe_mode == NO_SAFE_MODE) {
+        autoreload_enable();
+    }
+
+    // By default our internal flash is readonly to local python code and
+    // writable over USB. Set it here so that boot.py can change it.
+    filesystem_set_internal_concurrent_write_protection(true);
+    filesystem_set_internal_writable_by_usb(CIRCUITPY_USB == 1);
+
+    run_boot_py(safe_mode);
+
+    // Start USB after giving boot.py a chance to tweak behavior.
+    #if CIRCUITPY_USB
+    // Setup USB connection after heap is available.
+    // It needs the heap to build descriptors.
+    usb_init();
+    #endif
+
+    // Set up any other serial connection.
+    serial_init();
+
+    #if CIRCUITPY_BLEIO
+    bleio_reset();
+    supervisor_bluetooth_enable_workflow();
+    supervisor_start_bluetooth();
+    #endif
+
+    // Boot script is finished, so now go into REPL or run code.py.
+    int exit_code = PYEXEC_FORCED_EXIT;
+    bool skip_repl = true;
+    bool first_run = true;
+    bool simulate_reset;
+    for (;;) {
+        simulate_reset = false;
+        if (!skip_repl) {
+            exit_code = run_repl(first_run);
+            supervisor_set_run_reason(RUN_REASON_REPL_RELOAD);
+        }
+        if (exit_code == PYEXEC_FORCED_EXIT) {
+            if (!first_run) {
+                serial_write_compressed(translate("soft reboot\n"));
+            }
+            if (pyexec_mode_kind == PYEXEC_MODE_FRIENDLY_REPL) {
+                skip_repl = run_code_py(safe_mode, first_run, &simulate_reset);
+            } else {
+                skip_repl = false;
+            }
+        } else if (exit_code != 0) {
+            break;
+        }
+
+        // Either the REPL or code.py has run and finished.
+        // If code.py did a fake deep sleep, pretend that we are running code.py for
+        // the first time after a hard reset. This will preserve any alarm information.
+        first_run = simulate_reset;
+    }
+    mp_deinit();
+    return 0;
+}
+
+void gc_collect(void) {
+    gc_collect_start();
+
+    mp_uint_t regs[10];
+    mp_uint_t sp = cpu_get_regs_and_sp(regs);
+
+    // This collects root pointers from the VFS mount table. Some of them may
+    // have lost their references in the VM even though they are mounted.
+    gc_collect_root((void **)&MP_STATE_VM(vfs_mount_table), sizeof(mp_vfs_mount_t) / sizeof(mp_uint_t));
+
+    background_callback_gc_collect();
+
+    #if CIRCUITPY_ALARM
+    common_hal_alarm_gc_collect();
+    #endif
+
+    #if CIRCUITPY_ATEXIT
+    atexit_gc_collect();
+    #endif
+
+    #if CIRCUITPY_DISPLAYIO
+    displayio_gc_collect();
+    #endif
+
+    #if CIRCUITPY_BLEIO
+    common_hal_bleio_gc_collect();
+    #endif
+
+    #if CIRCUITPY_USB_HID
+    usb_hid_gc_collect();
+    #endif
+
+    #if CIRCUITPY_WIFI
+    common_hal_wifi_gc_collect();
+    #endif
+
+    // This naively collects all object references from an approximate stack
+    // range.
+    gc_collect_root((void **)sp, ((mp_uint_t)port_stack_get_top() - sp) / sizeof(mp_uint_t));
+    gc_collect_end();
+}
+
+void NORETURN nlr_jump_fail(void *val) {
+    reset_into_safe_mode(MICROPY_NLR_JUMP_FAIL);
+    while (true) {
+    }
+}
+
+#ifndef NDEBUG
+static void NORETURN __fatal_error(const char *msg) {
+    reset_into_safe_mode(MICROPY_FATAL_ERROR);
+    while (true) {
+    }
+}
+
+void MP_WEAK __assert_func(const char *file, int line, const char *func, const char *expr) {
+    mp_printf(&mp_plat_print, "Assertion '%s' failed, at file %s:%d\n", expr, file, line);
+    __fatal_error("Assertion failed");
+}
+#endif