Unstable Micropython on ESP8266

Question

I take my first steps in Micropythone on ESP8266. I uploaded the latest version 1.13 and when I try to run wifi in AP mode - strange things happen. Once every few wifi runs will work, but most often there is no response (I can't see wifi network from my computer). That's my code:

boot.py

# Libraries
import uos, machine, ujson
import gc

# Changing CPU from 80MHz to 160MHz
machine.freq(160000000)

# Load and check the config file
print('BOOT: Loading database.json...')

data = open('database.json', 'r')
config = ujson.load(data)
data.close()

# Config is corrupted
if config['Device']['Manufacture'] != 'ACME' or config['Checksum'] != '18caE':

  print('BOOT: database.json is corrupted! Uploading from backup.')

  # Copy clean from backup
  dataBackup = open('database-backup.json', 'r')
  configBackup = ujson.load(dataBackup)
  dataBackup.close()

  if configBackup:
    data = open('database.json', 'w')
    ujson.dump(configBackup, data)
    data.close()

    print('BOOT: Uploading from backup completed! Rebooting system...')

  # Reboot OS
  machine.reset()

# Config is correct
else:

  print('BOOT: database.json loading completed!')

  # Clean memory
  gc.collect()

main.py

# Libraries
import network, servers

print('MAIN: Loading module...')

servers.py

import network

print('SERVER: Loading module...')

# Setup Wi-Fi card
# As Access Point
if config['Configuration']['WiFiMode'] == 'Access Point':

  print('SERVER: Setup as Access Point')

  wifi = network.WLAN(network.AP_IF)
  wifi.active(True)
  wifi.config(essid = config['Device']['Name'] + ' ' + config['Device']['SerialNumber'], password = config['Configuration']['WiFiAPPassword'])
  wifi.ifconfig(('192.168.0.1','255.255.255.0','192.168.0.1','192.168.0.1'))

# As Wi-Fi client
elif config['Configuration']['WiFiMode'] == 'Client':

  print('SERVER: Setup as client ' + config['Configuration']['WiFiClientSSID'] + ' with password ' + config['Configuration']['WiFiClientPassword'])

else:
  machine.reset()

database.json

{
    "Device": {
        "Manufacture": "ACME",
        "Name": "My device",
        "SerialNumber": "M0J4"
    },
    "Configuration": {
        "WiFiAPPassword": "test1test",
        "WiFiAPIP": "192.168.0.1",
        "WiFiAPMask": "255.255.255.0",

        "WiFiClientSSID": "Network name",
        "WiFiClientPassword": "Network password",

        "WiFiMode": "Access Point",
    },
    "Checksum": "18caE"
}

Sometimes this code starts, but usually stops after boot.py. I'm broken down because I wrote a lot of code without ESP8266 and from 12 hours I'm tired of the very beginning...

Answer 1

A "global" variable is only global within a module. Your config variable is visible within main.py, boot.py, and the REPL because those all execute within the same context (the implicit __main__ module), but it won't be visible in other modules.

One solution is to move your config handling code into another module. E.g., create config.py with:

import gc
import json
import machine

config = {}


def load_config():
    global config

    # Load and check the config file
    print("BOOT: Loading database.json...")

    try:
        with open("database.json", "r") as fd:
            config = json.load(fd)
    except OSError:
        # failed to open file (maybe it didn't exist)
        config = {}

    # Config is corrupted
    if (
        config.get("Device", {}).get("Manufacture") != "ACME"
        or config.get("Checksum") != "18caE"
    ):

        print("BOOT: database.json is corrupted! Uploading from backup.")

        # Copy clean from backup
        with open('database-backup.json', 'r') as fd:
            configBackup = json.load(fd)

        with open('database.json', 'w') as fd:
            json.dump(configBackup, fd)

        print("BOOT: Uploading from backup completed! Rebooting system...")

        # Reboot OS
        machine.reset()
    # Config is correct
    else:

        print("BOOT: database.json loading completed!")

        # Clean memory
        gc.collect()

Then your boot.py becomes:

import machine
import gc

# Changing CPU from 80MHz to 160MHz
machine.freq(160000000)

gc.collect()

And servers.py looks like:

import config
import machine
import network

print("SERVER: Loading module...")


config.load_config()

# Setup Wi-Fi card
# As Access Point
if config.config["Configuration"]["WiFiMode"] == "Access Point":

    print("SERVER: Setup as Access Point")

    wifi = network.WLAN(network.AP_IF)
    wifi.active(True)
    wifi.config(
        essid="{} {}".format(
            config.config["Device"]["Name"],
            config.config["Device"]["SerialNumber"],
        ),
        password=config.config["Configuration"]["WiFiAPPassword"],
    )
    wifi.ifconfig(("192.168.0.1", "255.255.255.0", "192.168.0.1", "192.168.0.1"))

# As Wi-Fi client
elif config.config["Configuration"]["WiFiMode"] == "Client":

    print(
        "SERVER: Setup as client {} with password {}".format(
            config["Configuration"]["WiFiClientSSID"],
            config["Configuration"]["WiFiClientPassword"],
        )
    )

else:
    machine.reset()