Because of a careless mistake in my .git/config, I have pushed a merge of my original PR #154 to this upstream remote, which inadvertently also merged and closed that PR. This was never an intention and my PR still requires final review and confirmation by @ryan-summers and/or @jordens.

Therefore, I am opening a duplicate PR here, with some minor additional commits to what has already been reviewed in #154. Prior to this merge, I have force-pushed this upstream develop branch back to the original head (4ef6c80). Please kindly make all necessary corrections/actions if this is still the wrong develop head - Thank you with much apologies!

Summary

This PR is directly cloned from #154.

Key Changes

(based on #154)

• Introduce Cargo feature phy_enc424j600 for implementing MQTT client functionality with ENC424J600 controller
• Upon reboot, apply Booster's EEPROM EUI48 to ENC424J600's volatile RAM as MAC address
• Bump minimq to quartiq/minimq@d2ec3e8
• In following situations, eliminate panics or watchdog triggers on ENC424J600's variant while keeping trying to resume network connection:
  • MQTT broker IP address is invalid or currently cannot be connected
• Adopts smoltcp-nal 0.1.0 to implement the NAL stack required by minimq.
• Creates variants for CI.

Testing

Network connection and MQTT features remain functional for both ENC424J600 variant on v1.4 User IFC board and W5500 variant on v1.3 User IFC board (using default crate features).

Issues to be resolved independently

• MQTT client will not reconnect to the broker after disconnection.
• PHY linkup is not actively monitored, so if it is unplugged from the network, the socket TCP state keeps at ESTABLISHED (because there is no timeout/keepalive/socket close()), meaning in #[telemetry] the MQTT client will keep calling publish() to queue in the socket TX buffer until it is full, and keep emitting WriteFail errors.