OPENMV Bug: Alif lightsleep doesn't work anymore.

[kwagyeman]

Port, board and/or hardware

openmv-ae3

MicroPython version

Latest.

Reproduction

Call machine.lightsleep(). No way to wakeup.

Expected behaviour

Call machine.lightsleep() and you should be able to wakeup on RTC, button press, or dual core messaging.

Observed behaviour

When machine.lightsleep() is called the system dies. Wakeup from another core doesn't work either:

# This work is licensed under the MIT license.
# Copyright (c) 2013-2026 OpenMV LLC. All rights reserved.
# https://github.com/openmv/openmv/blob/master/LICENSE
#
# Dual-Core Wake-on-Speech Example
#
# This example puts the HP core into low-power lightsleep while the HE core
# continuously listens for keywords with MicroSpeech. When the HE core hears
# "Yes", the inter-core message wakes the HP core, which blinks an LED before
# going back to sleep.
#
# The built-in MicroSpeech model only recognizes the keywords "Yes" and "No".

import time
import openamp
import machine
from machine import LED


label = None


def task_callback(src_addr, data):
    global label
    label = data.decode()


@openamp.async_remote(task_callback)
async def task1(ept):
    from ml.apps import MicroSpeech
    speech = MicroSpeech(gain_db=24)
    while True:
        l, scores = speech.listen(timeout=0, threshold=0.70)
        if l:
            ept.send(l)


# Start the HE core.
rproc = openamp.RemoteProc(0x80320000)
rproc.start()

led = LED("LED_GREEN")

while True:
    if label == "Yes":
        for i in range(5):
            led.on()
            time.sleep_ms(250)
            led.off()
            time.sleep_ms(250)
        label = None
    # Sleep the HP core. The HE core keeps listening, and the inter-core
    # message from ept.send() wakes the HP core.
    machine.lightsleep()

Additional Information

No, I've provided everything above.

Code of Conduct

Yes, I agree

[kwagyeman]

@dpgeorge I think there's something wrong with lightsleep. This might because of the off profile update for deepsleep.

[dpgeorge]

@kwagyeman I can confirm that lightsleep cannot be woken. But I don't think wake-from-lightsleep was ever implemented on alif. I will look into it.

[dpgeorge]

@kwagyeman I did some more investigation into the case of HE waking HP from ligthsleep. It looks like you do need to first send a message from HP to HE before the endpoint is ready.

Here's the sequence that I found necessary on the HP side:

• create endpoint (can also be done after starting HE)
• start HE
• wait for endpoint to be ready via .is_ready()
• send a message on the endpoint via .send() -- at this point the HE will see that the endpoint is ready
• any messages sent from HE will now wake HP

---

Here's some test code.

For the HE, toggle the blue LED for 5 seconds then wake up HP via a message:

# run on HE

import time
import openamp
from machine import Pin

ept = openamp.Endpoint("vuart-channel")
led = Pin("LED_BLUE", Pin.OUT)

t0 = time.ticks_ms()
while True:
    time.sleep_ms(100)
    led.toggle()
    if time.ticks_diff(time.ticks_ms(), t0) > 5_000 and ept.is_ready():
        ept.send("wake")
        break
led.on()  # it's inverted

For the HP, start the HE and wait to be woken:

# run on HP

import time
import machine
import openamp
from machine import Pin

ept = openamp.Endpoint("vuart-channel")
led = Pin("LED_GREEN", Pin.OUT)
led.off()

rproc = openamp.RemoteProc(0x80320000)
rproc.start()
while not ept.is_ready():
    time.sleep_ms(100)
ept.send("test")
led.on()
machine.lightsleep()
led.off()  # it's inverted

That test works on current master.

[Tonnard]

Similar issue with deepsleep

Port, board and/or hardware

openmv-ae3

MicroPython version

Latest.

Reproduction

Call machine.deepsleep(). No way to wakeup.

Expected behaviour

Call machine.deepsleep() and you should be able to wakeup on RTC, button press,

Observed behaviour

When machine.deepleep() is called the system dies until power is cycled.

[kwagyeman]

@agatti This works on the AE3 with the latest OpenMV firmware on the tip of dev.

Tools->Install Latest Development firmware.