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diff --git a/examples/device/net_lwip_webserver/README.md b/examples/device/net_lwip_webserver/README.md new file mode 100644 index 000000000..b4d429100 --- /dev/null +++ b/examples/device/net_lwip_webserver/README.md @@ -0,0 +1,58 @@ +# Network Web Server (lwIP) + +A USB virtual network adapter that runs a small lwIP stack on the device, serving DHCP, DNS, and a web page over USB. + +## What it does + +- Brings up a USB network interface. Depending on the target MCU the build is either CDC-NCM (the default for most MCUs) or a dual RNDIS + CDC-ECM device that offers two configurations and lets the host pick its preferred one (Windows uses RNDIS, macOS uses CDC-ECM, Linux works with either). The NCM build also ships a BOS / Microsoft OS 2.0 descriptor so Windows auto-loads its NCM driver. +- The device takes IP address 192.168.7.1 and runs a DHCP server (handing out 192.168.7.2–192.168.7.4), a DNS server (resolves `tiny.usb`), and an HTTP server. +- Pressing the board button toggles the network link state (up/down) to simulate an Ethernet cable being unplugged/plugged. +- On higher-RAM MCUs it also starts an iperf TCP server for throughput testing. +- Blinks the board LED to indicate USB state (not mounted / mounted / suspended). + +## Requirements + +- Depends on the lwIP TCP/IP stack, fetched as a dependency (e.g. `python3 tools/get_deps.py`). + +## USB Descriptors + +| Interface | Class driver | +|-----------|--------------| +| 0–1 | Network (CDC-NCM, or CDC-ECM/RNDIS) | + +## Configuration + +Notable `tusb_config.h` settings: + +```c +// Network driver selection: NCM is the default; USE_ECM defaults to 0 but is +// forced to 1 on some MCUs (LPC15xx/40xx/51uxx/54, SAMD21/SAML2x, STM32F0/F1). +#define CFG_TUD_ECM_RNDIS USE_ECM // 0 by default -> ECM/RNDIS off +#define CFG_TUD_NCM (1 - CFG_TUD_ECM_RNDIS) // 1 by default -> NCM on + +// NCM tuning (see ncm.h for performance notes) +#define CFG_TUD_NCM_IN_NTB_MAX_SIZE 2048 +#define CFG_TUD_NCM_OUT_NTB_MAX_SIZE 4096 // 2048 on low-RAM MCUs +#define CFG_TUD_NCM_OUT_NTB_N 1 +#define CFG_TUD_NCM_IN_NTB_N 1 +``` + +## Building + +CMake: + +```bash +mkdir build && cd build +cmake -DBOARD=raspberry_pi_pico .. +cmake --build . +``` + +Make: + +```bash +make BOARD=raspberry_pi_pico all +``` + +## Try it + +A new USB network interface appears on the host. It is normally assigned an address in 192.168.7.x by the device's DHCP server (otherwise give the host NIC a static 192.168.7.x address), then browse to http://192.168.7.1 to load the served web page. |