SWAN R5: Sleep modes are broken

[bablokb]

CircuitPython version

Adafruit CircuitPython 8.2.9 on 2023-12-06; Swan R5 with STM32L4R5ZIY6

Code/REPL

def work():
  led.value = 1
  time.sleep(LED_TIME)
  led.value = 0

while True:
  # do some work
  work()

  # sleep
  if MODE == SPIN:
    next = time.monotonic() + INT_TIME
    while time.monotonic() < next:
      continue
  elif MODE == SLEEP:
    print(f"(normal) sleep for {INT_TIME}s")
    time.sleep(INT_TIME)
  elif MODE == LIGHT_SLEEP:
    print(f"(light) sleep for {INT_TIME}s")
    time_alarm = alarm.time.TimeAlarm(monotonic_time=time.monotonic()+INT_TIME)
    alarm.light_sleep_until_alarms(time_alarm)
  elif MODE == DEEP_SLEEP:
    print(f"(deep) sleep for {INT_TIME}s")
    time_alarm = alarm.time.TimeAlarm(monotonic_time=time.monotonic()+INT_TIME)
    alarm.exit_and_deep_sleep_until_alarms(time_alarm)

Behavior

With light-sleep, I can see the following current (at 3.6V):

So in light-sleep mode, the SWAN needs about 30mA. When the LED is on and the device sleeps normally (during work()), current is only about 16mA.

Deep-sleep is even more broken:

You can see that the device tries to switch to deep-sleep, but it wakes up again without actually sleeping (note that this is not fake deep-sleep, there was no USB connection). After wake up, you can see the 16mA during work() again, then the try-to-go-to-deep-sleep-and-fail cycle starts over.

Description

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Additional information

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