Add status and instructions in README.

README.md

@@ -1,6 +1,49 @@
 # cyw43
 
-Very WIP driver for the CYW43439 wifi chip, used in the Raspberry Pi Pico W.
+WIP 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).
+- Sending and receiving Ethernet frames.
+- Using the default MAC address.
+- [`embassy-net`](https://embassy.dev) integration.
+
+TODO:
+
+- AP mode (creating an AP)
+- GPIO support (used for the Pico W LED)
+- Scanning
+- Setting a custom MAC address.
+- RP2040 PIO driver for the nonstandard half-duplex SPI used in the Pico W. Probably porting [this](https://github.com/raspberrypi/pico-sdk/tree/master/src/rp2_common/cyw43_driver). (Currently bitbanging is used).
+- Using the IRQ pin instead of polling the bus.
+- Bus sleep (unclear what the benefit is. Is it needed for IRQs? or is it just power consumption optimization?)
+
+## Running the example
+
+- `cargo install probe-run`
+- `cd examples/rpi-pico-w`
+- Edit `src/main.rs` with your Wifi network's name and password.
+- `cargo run --release`
+
+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
+```
+
+The 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.
 
 ## License