alarm.sleep_memory corruption when pin_alarm (but not time_alarm) triggered during simulated and deep sleep

[jmangum]

CircuitPython version and board name

Adafruit CircuitPython 10.3.0-alpha.4 on 2026-07-23; Adafruit Feather ESP32S3 4MB Flash 2MB PSRAM with ESP32S3

Code/REPL

#
# Test deep sleep and alarm.sleep_memory interaction
# CP 10.3.0-alpha4
# 2026-08-02

import board
import busio
import time
import digitalio
import neopixel
from adafruit_datetime import datetime
from adafruit_onewire.bus import OneWireBus
#import adafruit_register
import keypad # Use for rain gauge and wind bird
import math
from analogio import AnalogIn
import struct
import alarm
#
# wifi setup libraries
import os
import ipaddress
import ssl
import wifi


print("\nESP32-S3 pin_alarm with alarm.sleep_memory and deep sleep test")

# Enable i2c_power pin to turn-on i2c power after sleep
i2c_power = digitalio.DigitalInOut(board.I2C_POWER)
i2c_power.direction = digitalio.Direction.OUTPUT
i2c_power.value = True

print("Setup wifi")

print(f"My MAC address: {[hex(i) for i in wifi.radio.mac_address]}")

print("Available WiFi networks:")
for network in wifi.radio.start_scanning_networks():
    print("\t%s\t\tRSSI: %d\tChannel: %d" % (str(network.ssid, "utf-8"),
                                             network.rssi, network.channel))
wifi.radio.stop_scanning_networks()

print(f"Connecting to {os.getenv('CIRCUITPY_WIFI_SSID')}")
wifi.radio.connect(os.getenv("CIRCUITPY_WIFI_SSID"), os.getenv("CIRCUITPY_WIFI_PASSWORD"))
print(f"Connected to {os.getenv('CIRCUITPY_WIFI_SSID')}")
print(f"My IP address: {wifi.radio.ipv4_address}")

ping_ip = ipaddress.IPv4Address("8.8.8.8")
ping = wifi.radio.ping(ip=ping_ip)

# retry once if timed out
if ping is None:
    ping = wifi.radio.ping(ip=ping_ip)

if ping is None:
    print("Couldn't ping 'google.com' successfully")
else:
    # convert s to ms
    print(f"Pinging 'google.com' took: {ping * 1000} ms")

print("Done with wifi setup")

def rain(rain_count, keys):
    # Listen for rain...
    #
    # Rain bucket size
    bucket_size = 0.2794
    pixel.fill((127, 255, 0))
    event = keys.events.get()
    # TODO: Get number of triggers rather an assuming each event is just one trigger (for ENS161 sleep rain meas)
    if event and event.key_number == 0 and event.pressed:
        rain_count += 1
        #print("Detected Rain: ", common.rain_count * bucket_size)
        print(event)
        print("Rain Total: ",rain_count * bucket_size," from ",rain_count," measurements")
        # Write to measurements dictionary
        #common.measurements['RainTot'] = common.rain_count * bucket_size
        #
    pixel.fill((0, 0, 0))
        #await asyncio.sleep(0) # NOTE: Rain and wind measurements must run continuously

#
# Start by (re)-enabling i2c_power after deep sleep with i2c_power=False (I2C power off)
i2c_power.value = True
#async def main():
# Enable i2c
#i2c = board.I2C()  # uses board.SCL and board.SDA
#i2c = board.STEMMA_I2C()  # For using the built-in STEMMA QT connector on a microcontroller
                           # Allows one to use all digital pins (D5 and D6 tested)
i2c = busio.I2C(board.SCL, board.SDA, frequency=100000) # Must use 100kHz frequency for i2c bus
                                                        # when PM2.5 sensor included

# Set up the LED
led = digitalio.DigitalInOut(board.LED)
led.direction = digitalio.Direction.OUTPUT
led.value = False

# Set up the neopixel
pixel = neopixel.NeoPixel(board.NEOPIXEL, 1)
pixel.brightness = 0.3

# Rain gauge pin assignment using keypad function
# Rain gauge: Detects bucket tip
rain_gauge_pin = board.A4
pins = (rain_gauge_pin, # Rain Gauge
        )
keys = keypad.Keys(pins, value_when_pressed=False, pull=True)

# Start with a clean-slate for rainfall measurements...
rain_count = 0

measurement_time = 120 # Send measurement to Gamera every measurement_time

# Check to see if pin or time alarm has triggered wake and act appropriately...
keys.deinit() # De-initialize keys to use rain pin as alarm

if isinstance(alarm.wake_alarm, alarm.pin.PinAlarm):
    for i in range(0,5): print("alarm.sleep_memory[",i,"]: ", alarm.sleep_memory[i])
    byte_string = bytes(alarm.sleep_memory[1:5])
    struct.unpack('f', byte_string)
    alarm_time = struct.unpack('f', byte_string)[0]
    print("Alarm Time After Pin Alarm Reset: ",alarm_time)
else:
    alarm_time = time.monotonic() + measurement_time
    print(alarm_time)
    # Store alarm_time in alarm.sleep_memory for recall if pin_alarm triggered
    print(struct.pack('f', alarm_time))
    byte_list = [byte for byte in struct.pack('f', alarm_time)]
    print(byte_list)
    for i in range(1,len(byte_list)+1): alarm.sleep_memory[i] = byte_list[i-1]
    for i in range(len(byte_list)+1): print("alarm.sleep_memory[",i,"]: ", alarm.sleep_memory[i])

time_alarm = alarm.time.TimeAlarm(monotonic_time=alarm_time)
pin_alarm = alarm.pin.PinAlarm(pin=rain_gauge_pin, value=False, edge=False, pull=True)

# HACK: Have to re-define keys here after deinit (even though defined above)...
keys = keypad.Keys(pins, value_when_pressed=False, pull=True)

print("alarm.wake_alarm: ",alarm.wake_alarm)

if isinstance(alarm.wake_alarm, alarm.pin.PinAlarm):
#if alarm.wake_alarm == pin_alarm:
    print('Woke from ',alarm.wake_alarm,'...rain...add one to alarm.sleep_memory[0]...')
    #my_common.rain_count += 1
    # Use sleep memory byte 0 to store rain count
    alarm.sleep_memory[0] = (alarm.sleep_memory[0] + 1) % 256 # Add one rain count to sleep memory
elif isinstance(alarm.wake_alarm, alarm.time.TimeAlarm):
    print('Woke from ',alarm.wake_alarm)
    rain_count = alarm.sleep_memory[0] # Read stored rain count to common rain_count variable for send
    rain(rain_count,keys)
    alarm.sleep_memory[0] = 0 # Reset rain count storage after send

keys.deinit()

print('Alarm Time: ',alarm_time)
runsleep = 60 # Allow access to REPL before deep sleep
print('Sleep with microcontroller power on and i2c power on for '+str(runsleep)+' seconds to allow access to REPL')
time.sleep(runsleep)
# Turn-off power to i2c devices before going to sleep
i2c_power.value = False # Turn-off i2c power during sleep
#time.sleep(5) # TEST...to see if green LEDs on i2c devices goes off...
#
print('Going to deep sleep for ',measurement_time,' seconds')
alarm.exit_and_deep_sleep_until_alarms(time_alarm,pin_alarm,preserve_dios=[i2c_power])
#alarm.exit_and_deep_sleep_until_alarms(time_alarm,pin_alarm)

Behavior

ESP32-S3 pin_alarm with alarm.sleep_memory and deep sleep test
Setup wifi
My MAC address: [REDACTED]
Available WiFi networks:
	REDACTED		RSSI: -43	Channel: 9
Connecting to REDACTED
Connected to REDACTED
My IP address: REDACTED
Pinging 'google.com' took: 11.0 ms
Done with wifi setup
353.287
b'\xbf\xa4\xb0C'
[191, 164, 176, 67]
alarm.sleep_memory[ 0 ]:  0
alarm.sleep_memory[ 1 ]:  191
alarm.sleep_memory[ 2 ]:  164
alarm.sleep_memory[ 3 ]:  176
alarm.sleep_memory[ 4 ]:  67
alarm.wake_alarm:  None
Alarm Time:  353.287
Sleep with microcontroller power on and i2c power on for 60 seconds to allow access to REPL
Going to deep sleep for  120  seconds
�]0;�192.168.0.82 | BLE:Off | Done | 10.3.0-alpha.4�\
Code done running.uto-reload is on. Simply save files over USB to run them or enter REPL to disable.

Press any key to enter the REPL. Use CTRL-D to reload.
Pretending to deep sleep until alarm, CTRL-C or file write.
Woken up by alarm.

==> Triggered rain sensor (pin_alarm) at this point, which woke-up microcontroller from deep sleep

| BLE:Off | code.py | 10.3.0-alpha.4�\
ESP32-S3 pin_alarm with alarm.sleep_memory and deep sleep test
Setup wifi
My MAC address: [REDACTED]
Available WiFi networks:
	REDACTED		RSSI: -48	Channel: 9
Connecting to REDACTED
Connected to REDACTED
My IP address: REDACTED
Pinging 'google.com' took: 13.0 ms
Done with wifi setup
alarm.sleep_memory[ 0 ]:  0
alarm.sleep_memory[ 1 ]:  0
alarm.sleep_memory[ 2 ]:  0
alarm.sleep_memory[ 3 ]:  0
alarm.sleep_memory[ 4 ]:  0
Alarm Time After Pin Alarm Reset:  0.0
Traceback (most recent call last):
  File "code.py", line 134, in <module>
ValueError: Time is in the past.
�]0;�192.168.0.82 | BLE:Off | Done | 10.3.0-alpha.4�\
uto-reload is on. Simply save files over USB to run them or enter REPL to disable.

Press any key to enter the REPL. Use CTRL-D to reload.

### Description

Tested with both 10.3.0-alpha4 and 10.2.1 and USB-computer and USB-power-only connection:

10.2.1 with USB-computer and USB-power-only connection:
- No issues with pin_alarm and sleep_memory
- Note that `preserve_dios = [i2c_power]` option in code above does not work with 10.2.1 due to #10790 

10.3.0-alpha4 with USB-computer connection:
- `alarm.sleep_memory` setting is preserved when time_alarm triggered after deep sleep
- `alarm.sleep_memory` setting is set to 0 for all entries used (indices 0 through 4) when pin_alarm triggered
- Triggering pin_alarm during time.sleep (not deep sleep) does not affect `alarm.sleep_memory` settings

10.3.0-alpha4 with USB-power-only connection:
- pin_alarm getting triggered randomly when microcontroller goes into deep sleep
- No REPL so no way to see what `alarm.sleep_memory` values are set to
- Behaviour independent of `preseverve_dios` setting in deep sleep

### Additional information

- Rain trigger (pin_alarm) confirmed during USB-power-only tests (no REPL) by using neopixel trigger (see code).
- Maybe unrelated by when using 10.3.0-alpha4 microcontroller does not eject USB from computer cleanly (while it does eject cleanly with 10.2.1).  Always get an error "Failed to eject...".  Can post as separate issue if needed.