# w5500-mqtt

MQTT v5 client for the [Wiznet W5500] SPI internet offload chip.

## Limitations

This is very basic at the moment, and will be expanded in the future.

* Does not support password protected MQTT servers.
* Only supports QoS 0: At most once delivery.

## Example

```rust
use w5500_mqtt::{
    ll::{
        net::{Ipv4Addr, SocketAddrV4},
        Sn,
    },
    Client, ClientId, Event, DST_PORT, SRC_PORT,
};

let mut client: Client = Client::new(
    Sn::Sn2,
    SRC_PORT,
    SocketAddrV4::new(Ipv4Addr::new(192, 168, 5, 6), DST_PORT),
);

// wait for a connection or die trying
while !matches!(client.process(&mut w5500, monotonic_secs())?, Event::None) {}

// publish to "duck" with a payload "quack"
client.publish(&mut w5500, "duck", b"quack")?;

// subscribe to "cow"
client.subscribe(&mut w5500, "cow")?;
```

## Relevant Specifications

* [MQTT Version 5.0](https://docs.oasis-open.org/mqtt/mqtt/v5.0/mqtt-v5.0.html)

## Feature Flags

All features are disabled by default.

* `eh0`: Passthrough to [`w5500-hl`].
* `eh1`: Passthrough to [`w5500-hl`].
* `defmt`: Enable logging with `defmt`. Also a passthrough to [`w5500-hl`].
* `log`: Enable logging with `log`.
* `w5500-tls`: Enable MQTT over TLS.
* `p256-cm4`: Passthrough to [`w5500-tls`].

[`w5500-hl`]: https://crates.io/crates/w5500-hl
[`w5500-tls`]: https://crates.io/crates/w5500-tls
[Wiznet W5500]: https://www.wiznet.io/product-item/w5500/