CHIP WiFi Echo Server Example

A prototype appplication that uses CHIP to setup WiFi on the ESP32 and runs an Echo Server on a configured port. This example will evolve as more complex messaging is supported in CHIP.

CHIP WiFi Echo Server Example
Supported Devices
Building the Example Application
Using the Echo Server

Supported Devices

The CHIP demo application is intended to work on two categories of ESP32 devices: the ESP32-DevKitC, and the M5Stack. On the M5Stack this example displays a CHIP QRCode with the device's Soft-AP SSID encoded in the TLV section.

Building the Example Application

Building the example application requires the use of the Espressif ESP32 IoT Development Framework and the xtensa-esp32-elf toolchain.

The VSCode devcontainer has these components pre-installed, so you can skip this step. To install these components manually, follow these steps:

Clone the Expressif ESP-IDF and checkout version 4.0

  $ mkdir ${HOME}/tools
  $ cd ${HOME}/tools
  $ git clone https://github.com/espressif/esp-idf.git
  $ cd esp-idf
  $ git checkout release/v4.0
  $ git submodule update --init
  $ export IDF_PATH=${HOME}/tools/esp-idf
  $ ./install.sh

To build the application, follow these steps:

Currently building in VSCode and deploying from native is not supported, so make sure the IDF_PATH has been exported(See the manual setup steps above).

In the root of the example directory, sync the dependencies and source idf.sh. Note: This does not have to be repeated for incremental builds.
```
  $ make -C third_party/connectedhomeip -f Makefile-bootstrap repos
  $ source idf.sh
```
Next, if you want to use the M5Stack with its display and show a QRCode run menuconfig.
```
  $ idf make menuconfig
```
While in the configurator, navigate to WiFi Echo Demo->Device Type and select M5Stack.
Otherwise, run the default config.
```
  $ idf make defconfig
```
Run make to build the demo application.
```
  $ idf make
```
After building the application, to flash it outside of VSCode, connect your device via USB. Then run the following command to flash the demo application onto the device and then monitor its output. If necessary, replace /dev/tty.SLAB_USBtoUART(MacOS) with the correct USB device name for your system(like /dev/ttyUSB0 on Linux). Note that sometimes you might have to press and hold the boot button on the device while it's trying to connect before flashing. For ESP32-DevKitC devices this is labeled in the functional description diagram.
```
  $ idf make flash monitor ESPPORT=/dev/tty.SLAB_USBtoUART
```
Note: Some users might have to install the VCP driver before the device shows up on /dev/tty.
Quit the monitor by hitting Ctrl+].
Note: You can see a menu of various monitor commands by hitting Ctrl+t Ctrl+h while the monitor is running.

If desired, the monitor can be run again like so:

  $ idf make monitor ESPPORT=/dev/tty.SLAB_USBtoUART

Using the Echo Server

There are two ways to use the Echo Server running on the device.

Connect the ESP32 to a 2.4GHz Network of your choice

To connect the device to your network, give it the network details via the menuconfig target.
```
        $ idf make menuconfig
```
While in the configurator, navigate to Component Config->CHIP Device Layer->WiFi Station Options and fill out the WiFi SSID and Password.
Now flash the device with the same command as before. (Use the right /dev device)
```
        $ idf make flash monitor ESPPORT=/dev/tty.SLAB_USBtoUART
```
The device should boot up and connect to your network. When that happens you will see a log like this in the monitor.
```
        I (5524) chip[DL]: SYSTEM_EVENT_STA_GOT_IP
        I (5524) chip[DL]: IPv4 address changed on WiFi station interface: <IP_ADDRESS>...
```
Note: If you are using the M5Stack, the screen will display the server's IP Address and Port if it successfully conencts to the configured 2.4GHz Network.
Then running the following command will ping the ESP32 and cause it to echo. If necessary replace the <IP_ADDRESS> with the address printed by the device in the monitor.
```
        $ echo "Hello over IP" | nc -w1 -u 192.168.4.1 8000
```

Note: The ESP32 does not support 5GHz networks. Also, the Device will persist your network configuration. To erase it, simply run.

            $ idf make erase_flash ESPPORT=/dev/tty.SLAB_USBtoUART

Use the ESP32's Network

Alternatively, you can connect to the ESP32's Soft-AP directly.

After the application has been flashed, connect to the ESP32‘s Soft-AP. If you use the M5Stack, the Soft-AP’s SSID is encoded in the TLV section of the QRCode on screen. It‘s usually something like CHIP_DEMO-XXXX where the last 4 digits are from the device’s MAC address.
Once you‘re connected, the server’s IP can be found at the gateway address and at the listed port number(Default: 8000).
Then running the following command will ping the ESP32 and cause it to echo. If necessary replace the 192.168.4.1 with the address printed by the device in the monitor.
```
      $ echo "Hello over IP" | nc -w1 -u 192.168.4.1 8000
```