Light sleep: crash on wakeup

[Jean-François Milants]

Hi!

I'm working on a project using a Lopy (wifi/ble/lora) board. The board is a bit old, but I upgraded the firmware yesterday (1.20.2.r1).

I would like to put the Lopy into light sleep (maybe deep sleep later) and wake it up every 1 minutes or when a button is pushed.
The button is connected on P23 (G10 on the base board) and GND.

Here is my code:

import pycom
from machine import Pin
import machine

pycom.heartbeat(False)

print("Initializing input pin...")
p_in = Pin('P23', mode=Pin.IN, pull=Pin.PULL_UP)
machine.pin_sleep_wakeup(['P23'], machine.WAKEUP_ALL_LOW, True)

print("Entering main loop...")
while True:
    print("RUN")
    machine.sleep(60000)
    print("WAKE")

It works fine when I run the file interactively using Pymakr, but it doesn't work when I upload the file to the lopy, and reset it to run it at boot : it crashes and reboots every time it wakes up (either after 60s or when I push the button):

Initializing input pin...
Entering main loop...
RUN
Guru Meditation Error: Core  0 panic'ed (StoreProhibited). Exception was unhandled.
Core 0 register dump:
PC      : 0x40095eb3  PS      : 0x00060e33  A0      : 0x80088f34  A1      : 0x3ffb7130  
A2      : 0x00000000  A3      : 0x00060e20  A4      : 0x00000001  A5      : 0x0000cdcd  
A6      : 0xb33fffff  A7      : 0x3ffdc6f4  A8      : 0x0000abab  A9      : 0x3ffb7130  
A10     : 0x00000003  A11     : 0x0000cdcd  A12     : 0x00060e20  A13     : 0x00000000  
A14     : 0x3ffb2740  A15     : 0x3ffb2d91  SAR     : 0x00000000  EXCCAUSE: 0x0000001d  
EXCVADDR: 0x00000000  LBEG    : 0x40092cd4  LEND    : 0x40092d02  LCOUNT  : 0xffffffff  

ELF file SHA256: 0000000000000000000000000000000000000000000000000000000000000000

Backtrace: 0x40095eb3:0x3ffb7130 0x40088f31:0x3ffb7160 0x40086d09:0x3ffb7180 0x401432c6:0x3ffb71c0 0x400d249c:0x3ffb71e0

================= CORE DUMP START =================
7DMAAAEAAAAPAAAAbAEAAA==
fHL7P3Bw+z90cvs/
<< GARBAGE >>

Do I need to do something special to make it work correctly?

Thanks!

[Jean-François Milants]

I've just changed the version to Pycom MicroPython 1.20.0.rc13 [v1.9.4-94bb382] on 2019-08-22; LoPy with ESP32 (legacy firmware) and light sleep works as expected. I'm not sure I understand the difference between different driver types, but I don't use pybyte, so it should be ok.

Could it be a bug in the pybyte firmware?