ESP32 light sleep issues (resolved)

[frazzmatazz]

Is there a way to keep an SPI (or i2c?) OLED on during light sleep?

I'm making a custom alarm clock (I get up at different times each day), with battery back up, that could hopefully run in a low power mode for a week+.

ESP32 in a busy loop or sleep(x) uses about 30-40 mA. With a 2.4" SSD1309 display with only 30-40 pixels lit (like the picture) there's no appreciable change in power consumption, vs displaying nothing. Large text takes total up to 100-120mA. No screen attached is still in the 30+mA range.

Light sleep seems perfect, it can resume with current memory etc. Power consumption is so low I can't measure it. But the OLED goes off.

Id love it if I could use light sleep, and update the OLED once a minute and keep it on.

Any ideas?

[davefes]

Would using the hold parameter on any GPIO during lightsleep keep the OLED going?

flash = Pin(4,Pin.OUT, hold=False)

flash.init(hold=True)
lightsleep(60000)
flash.init(hold=False)

[frazzmatazz]

I just tried pulling out the jumper wires one at a time: CS, DC, RST, MOSI, CLK and the display stays on and holds the display! Plug them in again and update the clock and there's no issue.
Implying it is actively being turn off during light sleep and the pin output isn't important.

Unless the 3.3v pin I am using for power gets shutdown during light sleep... Where's my multimeter...

[frazzmatazz]

OK! it's working! using 6-12mA (inaccurate) during light sleep displaying "13:58" in a 3x5 pixel font.

This might be a board specific issue I was having, or perhaps related to specific pins.
It works on a Lolin D32 (ESP32-WROOM-32 modules) using these pins:
spi = SPI(1, baudrate=10000000, sck=Pin(22), mosi=Pin(23))
display = Display(spi, rst=Pin(21), dc=Pin(19), cs=Pin(18))

I was having problems with a Wemos C3 Pico (ESP32-C3).
spi = SPI(1, baudrate=10000000, sck=Pin(1), mosi=Pin(4))
display = Display(spi, dc=Pin(0), cs=Pin(2), rst=Pin(5))

I'll try and reproduce the problem later.

[frazzmatazz]

Next problem. I can't get GPIO to wake from light sleep. Or it's not working how I expected.

Is it meant to exit the light sleep? (maybe not from examples I see)
or does it just call and process the function and continue lightsleep waiting for the timeout? (if so I can't do it reliably.)

from machine import Pin, SPI, RTC, lightsleep, PWM, SLEEP 

def wakebutton(pin):
   print("...")
   global lastupdate # time last updated clockface
   global displaystatus  # clockface to show
   global lastbuttonpush # time last button push registered (to try and debounce)
   if lastbuttonpush + 1 < time.time():
       lastupdate = time.time() - 60
       displaystatus = displaystatus + 1
       lastbuttonpush = time.time()
       if displaystatus > 3: displaystatus = 0
       print(lastupdate, displaystatus)

pin = Pin(15, Pin.IN, Pin.PULL_UP)
pin.irq(trigger=Pin.IRQ_FALLING, handler=wakebutton, wake=SLEEP)

[davefes]

The problem with GPIO waking for lightsleep remains.

Maybe, a specific test script for "waking from lightsleep" for both the ESP32 and the ESP32-C3 might provide a clue.

[frazzmatazz]

It turns out I need to import ESP32 and use a specific esp32.wake_on_ext0. I think there's a hardware specfic issue hinted at in other forum posts, and I found tips here: https://github.com/orgs/micropython/discussions/10767.

This works on the ESP32 Lolin D32. I havne't tried the ESP32C3 yet.:

from machine import Pin, RTC, lightsleep, SLEEP # type: ignore
import time
import esp32

def TZtime(UTC_OFFSET=+10):
    return time.gmtime(time.time() + UTC_OFFSET * 3600)

pin = Pin(15, Pin.IN, Pin.PULL_UP)
esp32.wake_on_ext0(pin = pin, level = esp32.WAKEUP_ANY_HIGH)

while True:
    t = TZtime()
    timestamp = '{:02d}:{:02d}:{:02d}'.format(t[3], t[4], t[5])
    
    print(timestamp)
    sleep(1)
    #sleep(15)
    lightsleep(19000) #while pin15 is held low light sleep works and exits when high.

Except WAKEUP_ANY_LOW doesn't work. Which is inconvient for my current wiring/buttons.
AttributeError: 'module' object has no attribute 'WAKEUP_ANY_LOW'

The ?traditional approach of

pin = Pin(15, Pin.IN, Pin.PULL_UP)
pin.irq(trigger=Pin.IRQ_FALLING, handler=wakebutton, wake=SLEEP) 

doesn't work. It just goes into a timed lightsleep and doesn't wake or call the wakebutton function:

from machine import Pin, RTC, lightsleep, SLEEP # type: ignore
import time
import esp32

sleep(3)
displaystatus = 0
lastbuttonpush = 0

def wakebutton(pin):
   #print("...")
   global displaystatus
   global lastbuttonpush
   if lastbuttonpush + 0.1 < time.time():
       displaystatus = displaystatus + 1
       lastbuttonpush = time.time()
       if displaystatus > 3: displaystatus = 0
       print(lastbuttonpush, displaystatus)

def TZtime(UTC_OFFSET=+10):
    return time.gmtime(time.time() + UTC_OFFSET * 3600)

pin = Pin(15, Pin.IN, Pin.PULL_UP)
pin.irq(trigger=Pin.IRQ_FALLING, handler=wakebutton, wake=SLEEP)

while True:    
    t = TZtime()
    timestamp = '{:02d}:{:02d}'.format(t[3], t[4])
    
    print(timestamp, displaystatus, lastbuttonpush)
    sleep(1)
    #sleep(15)
    lightsleep(9000)

Is this just a hardware (ESP32) specific thing?, and I should just use esp32.wake_on_ext0(pin = pin, level = esp32.WAKEUP_ANY_HIGH). Why doesn't WAKEUP_ANY_LOW work? (it won't run) Seems like a bug.

Thanks!

[davefes]

https://github.com/orgs/micropython/discussions/10767 for your last question.

I don't see any difference between your last code snippet and the shorter previous one.

[frazzmatazz]

From that link it seems like I need WAKEUP_ALL_LOW. And that does work fine for me since I only have one button for wake up.
WAKEUP_ANY_LOW isn't available due to hardware restrictions it seems.

That last code snippet is based on all the online examples of interupting lightsleep, but doesn't work on ESP32, probably not in ESP32C3 either (untested yet).
I've found some references to this in the manual now!
https://docs.micropython.org/en/latest/library/esp32.html#module-esp32
https://docs.micropython.org/en/latest/esp32/quickref.html#deep-sleep-mode

[davefes]

Maybe the problem is that you need to poll for the IRQ in the while loop?

In my ESP32-CAM:

wake_source = Pin(13, Pin.IN)  # setting wake up pin
esp32.wake_on_ext0(pin = wake_source, level = esp32.WAKEUP_ANY_HIGH)   # initialising wake up


while True:
    lightsleep(9000)

    if (wake_source.value() == 1):
        do_something()