The Startup Sequence

After a reboot or when powering up the network connection needs to be established or configured and the operating mode is chosen based on counting reset cycles.

Many things may happen when a device is staring and even a given configuration can fail. The startup sequence of a device actually is the critical part of the implementation to avoid loosing a device in a unrecoverable state.

The Normal Startup

In a full configured device the startup is using the following steps:

The root file system is initialized.
The env.json configuration file is used to create the device specific elements.
The config.json configuration file is used to create the application specific elements.
The elements marked with startup=sys are started. This usually includes the display.
Some Greeting information is given to the display and Serial logging.
The network connection is started (see below)
The elements marked with startup=net are started. This usually includes most of the elements.

When there is a time giving element present:

The network time is retrieved.
The elements marked with startup=time are started when a valid time is given. This includes e.g. alarm elements.

Then the “normal” operation mode is reached, the loop() function is called on the elements one-by-one and upcomming actions are dispatched to their target element.

[ ] 5 minutes startup timeout to restart [ ] 60 seconds runtime to set the reset counter to 0

There are several operating modes implemented that help in network and device configurations and allow even starting a device without or with a wrong configuration. This is based on the available network configuration and a counter of the latest reset cycles.

The network configuration is given by the WiFi Manager.

The reset counter is incremented immediately after the restart of the device and is set to the value 0 after successfully running a device for at least 60 seconds.

A reset can be enforced by powering off and on the device or by using the RST / EN button that is available on many boards.

Sometimes the wireless network is not available and a configured network connection can not be established. In this case the device will restart after 5 minutes with a reset counter set to 0. This allows starting in a normal operation mode after a network dropout.

Captive Mode

This mode is automatically chosen when no network configuration is given or after several resets in a row.

In this operating mode an access point is created with a name HomeDing-xxxxxx using the last 6 digits of the MAC adddress of the board. Any client can connect to this access point and can access the WiFi Setup Dialog of the WiFi Manager.

In this mode NO configured element will be activated.

Using the WiFi Setup Dialog the network connection details can configured and persisted on the board.

The reset counter is always set to 0 after successfully running the captive mode or by updating a new network connectivity.

Normal Run Mode

This mode is enabled when the reset counter has the value 1.

This is the regular working mode for a configured device.

All configured Elements created.
The last state information of elements is given to the elements.
The System Elements are started.
When network is available the Elements requiring a Network are started.
When a current time is available the Elements requiring a current time are started.

When the secure property is set in the device configuration some device configuration functionality is disabled protect.

Unsecure Run Mode

This mode is enabled when the reset counter has the value 2. It can be enabled by resetting or re-powering the device twice within 60 seconds. This mode and behaves exactly like the Normal Run Mode in the non-secure mode.

This mode is available for enabling OTA updates on devices with the secure property is set in the device configuration.

Bare Run Mode

This mode is enabled when the reset counter has the value 3.

The network configuration is used for network connectivity.
Only a [Device element] and an [OTA Element] is created without loading any configuration file.

This results in a device using a generic name like ESP-xxxxxx or ESP32-xxxxxx. on the local network.

The Web Server files can be uploaded and the device can be configured through uploaded configuration files or the integrated IDE functionality.

Enforced Captive Mode

This mode is enabled when the reset counter has the value 4 or greater. The device runs the Captive mode described above.

When the Captive mode is unused for 5 minutes or ended by configuring a new network connectivity the reset counter is set to 0 and a restart is executed.

Startup logging output

The following samples will show you how the startup sequence is shown in the log and explains the output in detail.

Device Startup on first time

After uploading the HomeDing firmware the very first time the log output will show the following messages:

00:00:06 >Device DevDing starting...
00:00:06 >formatting...
00:00:06 >setup done
00:00:06 >Captive Mode: HomeDing123A45

The Device ____ starting... messages is showing the name of the sketch (example) that is used.

The formatting... message is shown because the filesystem will be created during this very first start sequence.

The setup done messages is created at the end of the Arduino startup() function just before the loop() will start.

The Captive Mode: HomeDingNNNNNN message is shown when an Access point is created with the given name for starting a network configuration with the [WiFi Manager].

This sequence of messages will also happen when uploading the firmware with the Erase All Flash Before Sketch Upload: Enabled option.

Device Startup without configuration

When no network configuration is available the device will immediately start into the Captive mode.

00:00:06 >Device DevDing starting...
00:00:06 >setup done
00:00:06 >Captive Mode: HomeDing123A45

After 5 minutes without using the captive mode the device will restart:

00:05:06 >no config.
00:05:06 >reboot...

The no config. message is shown after 5 minutes without getting a network configuration.

The reboot... message is shown because a reboot was initiated.

Network configuration

In Captive mode, when a configuration is given using the [WiFi Manager] the following logs are created:

00:02:39 >setup network ____
00:02:44 >ok. 
00:02:44 >reboot...

The setup network ____ message is shown when a new network configuration is received.

The ok. message is shown when the network connection was successful.

The reboot... message is shown because a reboot was initiated.

Regular Startup Without Configuration

The startup mesages on a regular boot when no configuration is available (or is not used in bare mode) look like:

00:00:06 >Device DevDing starting...
00:00:06 >setup done
00:00:06 >HomeDing
00:00:06 >connect as 'esp32-123a45' to WiFI DEVNET...
00:00:12 >esp32-123a45 192.168.2.206
00:00:12 >connected to DEVNET (unsafe mode)
00:00:12 >start http://esp32-123a45/

HomeDing Greeting This message is also shown on an attached and configured display.

connect as 'esp32-123a45' to WiFI DEVNET... – devicename and network name used for connecting

esp32-123a45 192.168.2.206 - successful connected to the network with the devicename and IP address. This message is also shown on an attached and configured display.

start http://esp32-123a45/

Regular Startup

The following startup mesages are created for a configured device (name=“hdboard”) and safemode enabled. They look similar to the messages written when no element configuration is given but the devicename is taken from the device Element.

00:11:09 >Device DevDing starting...
00:11:09 >setup done
00:11:09 >HomeDing 
00:11:09 >connect as 'hdboard' to WiFI DEVNET...
00:11:12 >hdboard 192.168.2.206
00:11:12 >connected to DEVNET (safe mode)
00:11:12 >start http://hdboard/

2. reset in between 60 seconds

When a second reset or reboot is executed without having 60 seconds of normal operating time the device will start in unsafe mode and the connected message will look like:

00:15:22 >Device DevDing starting...
00:15:22 >setup done
00:15:22 >reset #2
00:15:22 >HomeDing 
00:15:22 >connect as 'hdboard' to WiFI DEVNET...
00:15:23 >hdboard 192.168.2.206
00:15:23 >connected to DEVNET (unsafe mode)
00:15:23 >start http://hdboard/

The reset #2 message shows the internal reset counter.

3. reset in between 60 seconds

When a third reset or reboot is executed without having 60 seconds of normal operating time the device will start in bare mode. In this mode the device will start using the network configuration but no device configuration file will be used. The message sequence will look like:

00:00:06 >Device DevDing starting...
00:00:06 >setup done
00:00:06 >reset #3
00:00:06 >HomeDing 
00:00:06 >connect as 'esp32-123a45' to WiFI DEVNET...
00:00:08 >esp32-123a45 192.168.2.206
00:00:08 >connected to DEVNET (unsafe mode)
00:00:08 >start http://esp32-123a45/

The reset #3 message shows the internal reset counter.

The same devicename is used that is used on booting without configuration. The IP address will likely be the same.

4. reset in between 60 seconds

When a forth reset or reboot is executed without having 60 seconds of normal operating time the captive mode is started without connecting the device to a local network.

00:00:06 >Device DevDing starting...
00:00:06 >setup done
00:00:06 >reset #4
00:00:06 >Captive Mode: HomeDing123A45

The reset #4 message shows the internal reset counter.

The reset counter is set to 0 after successfully running the captive mode or after updating the network connectivity.