cyw43 0.2.0

Rust driver for the CYW43439 WiFi chip, used in the Raspberry Pi Pico W.
Documentation
# cyw43

Rust driver for the CYW43439 wifi chip, used in the Raspberry Pi Pico W. Implementation based on [Infineon/wifi-host-driver](https://github.com/Infineon/wifi-host-driver).

## Current status

Working:

- Station mode (joining an AP).
- AP mode (creating an AP)
- Scanning
- Sending and receiving Ethernet frames.
- Using the default MAC address.
- [`embassy-net`]https://embassy.dev integration.
- RP2040 PIO driver for the nonstandard half-duplex SPI used in the Pico W.
- Using IRQ for device events
- GPIO support (for LED on the Pico W)

TODO:

- Setting a custom MAC address.
- Bus sleep (for power consumption optimization)

## Running the examples

- Install `probe-rs` following the instructions at <https://probe.rs>.
- `cd examples/rp`
### Example 1: Scan the wifi stations
- `cargo run --release --bin wifi_scan`
### Example 2: Create an access point (IP and credentials in the code)
- `cargo run --release --bin wifi_ap_tcp_server`
### Example 3: Connect to an existing network and create a server
- `cargo run --release --bin wifi_tcp_server`

After a few seconds, you should see that DHCP picks up an IP address like this
```
11.944489 DEBUG Acquired IP configuration:
11.944517 DEBUG    IP address:      192.168.0.250/24
11.944620 DEBUG    Default gateway: 192.168.0.33
11.944722 DEBUG    DNS server 0:    192.168.0.33
```
This example implements a TCP echo server on port 1234. You can try connecting to it with:
```
nc 192.168.0.250 1234
```
Send it some data, you should see it echoed back and printed in the firmware's logs.