No reconnect after loosing connection for a "long" time

[HugoMcKinley]

Version: 2.10.1 with EthernetShield(W5100) on Nano and Mega (can't get V3.x to run with ethernet)
Used modules: DigitalInput, DigitalOutput, I2c, OneWire und FirmataExt

If the server(here FHEM) is not responding for a (long) while firmata doesn't reconnect.
If the time is short (i.e. reboot of the Server) firmata reconnects if the Server is back online.

I think the problem is overflowing RAM, because the Mega has more memory so it can "handle" a longer time without connection to the server.
It looks like if firmata can't get out the data and ram is filling. If the reconnect happens before the memory is full, it reconnects to the server, but if the time is too long and the memory is full then the Arduino doesn't reconnect to the Server.

Power off and on, or pressing the reset button fix the problem until the next "long" disconnect.

I implemented the Watchdog of [https://github.com//issues/47], but it didn't help.
I tested the watchdog with a test-sketch and it works.

[PizzaProgram]

I'm trying to do similar to RPi-Pico,
but the repeat-timer functions are turned off at the SDK.
First, I would like to simply blink the LED to see, if Firmata is still running stable:

#include <pico/time.h>
static struct repeating_timer timer;

// Timer callback function  
bool led_blink_callback(struct repeating_timer *t) {
    bool ledState = digitalRead(VERSION_BLINK_PIN); // Read current LED state using Firmata's function
    digitalWrite(VERSION_BLINK_PIN, !ledState); // Toggle LED state
//  bool led_state = gpio_get(VERSION_BLINK_PIN); 
//  gpio_put(VERSION_BLINK_PIN, !led_state); 
    return true; // Keep repeating the timer
}

void led_blink_setup() {
    pinMode(VERSION_BLINK_PIN, OUTPUT);
    alarm_pool_add_repeating_timer_us(alarm_pool_get_default(), 250000, led_blink_callback, NULL, &timer);
//  add_repeating_timer_us(250000, led_blink_callback, NULL, &timer); // Blink 2x pro second
}

error: 'alarm_pool_get_default' was not declared in this scope
because:
PICO_TIME_DEFAULT_ALARM_POOL_DISABLED is always = 1.
Even if I try to override it at the beginning, because it does not allow to re-declare.

[pgrawehr]

@HugoMcKinley I'm not sure, but I think the V2.10 could be the issue. I have fixed a few connection-related issues for V3.0, and most of the networking code is actually new. I don't have an EtherShield, so I can't test the ethernet connection with those boards, but it might be worth to get that to work with 3.X. You can have a look at the new ethernet code (I tested it on an ESP32, though, which is a much more powerful CPU than the nano).