doc(examples/esp-node): add a README

Author: etiennedm

examples/esp-node/README.md

@@ -0,0 +1,37 @@
+This is a dummy CANopen node that runs on an ESP32C3 microcontroller.
+
+# Prerequisite Tools
+
+To flash the microcontroller through a USB-UART adapter the `espflash` utility is used as defined in `.cargo/config.toml`.
+Install it with:
+```bash
+cargo install cargo-espflash --locked
+```
+
+You can check that the target device is detected:
+```bash
+espflash board-info
+```
+
+# Build and Run
+Build the firmware and flash it to the target:
+```bash
+cargo run
+```
+
+Bring up the CAN interface at 125kbit/s on your host computer:
+```bash
+sudo ip link set can0 up type can bitrate 125000
+```
+
+Use the zencan CLI to scan for the ESP node:
+```bash
+cargo run --bin zencan-cli can0
+
+can0>scan                                                                                  Nodes: 1
+Node 24: PreOperational
+    Identity vendor: CAFE, product: 408, revision: 1, serial: FA186B18
+    Device Name: 'esp-node'
+    Versions: '001' SW, '1' HW
+    Last Seen: 0s ago
+```