first and working ethernet

README_ETH.md

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+# RP2040-ETH WS2812 Network Control
+
+This implementation adds ethernet connectivity to the WS2812 LED control, allowing you to control the LED color over the network.
+
+## Hardware Setup
+
+- **Board**: Waveshare RP2040-ETH
+- **LED**: WS2812 connected to GPIO 25
+- **Ethernet**: CH9120 chip handles TCP/IP communication
+
+## Network Configuration
+
+Default settings (can be modified in `ch9120.c`):
+- **IP Address**: 192.168.1.200
+- **Port**: 1000
+- **Mode**: TCP Client
+- **Target IP**: 192.168.1.10
+- **Target Port**: 2000
+
+## Building
+
+```bash
+cd build
+cmake ..
+make barnum_eth
+```
+
+## Flashing
+
+1. Hold BOOTSEL button and connect USB
+2. Copy `barnum_eth.uf2` to the RPI-RP2 drive
+3. The board will reboot automatically
+
+## Usage
+
+### Supported Commands
+
+Send these commands as TCP messages to control the LED:
+- `RED` - Set LED to red
+- `GREEN` - Set LED to green  
+- `BLUE` - Set LED to blue
+- `WHITE` - Set LED to white
+- `OFF` - Turn LED off
+- `RGB:r,g,b` - Set custom color (e.g., `RGB:255,128,0` for orange)
+
+### Python Test Client
+
+Use the included `test_client.py` to test:
+
+```bash
+# Run demo sequence
+python3 test_client.py
+
+# Send single command
+python3 test_client.py "RGB:255,0,255"
+```
+
+### Features
+
+- Smooth color transitions between commands
+- Network status feedback via USB serial
+- Acknowledgment messages for each command
+
+## Pin Assignments
+
+- **WS2812 Data**: GPIO 25
+- **UART TX (CH9120)**: GPIO 20
+- **UART RX (CH9120)**: GPIO 21
+- **CFG (CH9120)**: GPIO 18
+- **RES (CH9120)**: GPIO 19
+
+## Troubleshooting
+
+1. **No network connection**: 
+   - Check ethernet cable is connected
+   - Verify IP settings match your network
+   - Use serial monitor to see debug output
+
+2. **LED not responding**:
+   - Verify WS2812 is connected to GPIO 25
+   - Check power supply to LED
+   - Monitor serial output for errors
+
+3. **Can't flash the board**:
+   - Make sure to use the correct board setting in CMakeLists.txt
+   - The board type is already set to `waveshare_rp2040_eth`