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ESP8266 - Espressif

Manufacture: Espressif
Device Type: Wifi Adapter
Interface: UART
Features: 2.4 GHz
802.11 b/g/n
Device Page  

Compatible Setups

The following table shows which setups were tested with this device, including the setup details and date of test:

Hardware / Firmware VersionModule (Version)Board (Version)OS (OS / BSP Version)NoteTest Date
- / -Colibri iMX6ULL (V1.1B)Iris (QM 4GB WB IT V1.0A)Yocto (Linux) (3.0)

Tested with SLIP bridge


Using ESP8266 (ESP12 with NodeMcu board) as Wi-Fi interface on Linux via SLIP (Serial Line IP)

It is possible to use the popular ESP8266 board as a Wi-Fi adapter for embedded Linux systems by making use of the SLIP (Serial Line IP) protocol. This allows an internet connection to be routed via common RX and TX serial lines.

Note: Toradex does not recommend or endorse this WiFi chip /module, this article is just an example showing how this WiFi solution could be used on our platform. It is the developers' responsibility to evaluate the reliability and other parameters before putting it on to the design.

Install the SDK and the ESP8266 firmware

On your host computer, download and install esp-open-sdk. You can test it by compiling and uploading the "blinky" example to the board.

In another directory, clone the esp_slip_router repository. Modify the Makefile to change the BUILD_AREA environment variable. Modify user/user_config.h with your desired settings, such as SSID and password.


$ make

if compilation is successful, flash the compiled firmware to your board (which must be connected via USB, if using a NodeMCU board) with

$ make flash

after flashing, the board should automatically reset.

Hardware connection

If using the NodeMCU board, connect its RX and TX pins to the TX and RX pins of your Linux board, respectively.

Don't forget to connect the GND and 3.3V pins.

Installing dependencies

You'll need to install the net-tools package. It is not available in the Ångström feeds, so you must build it using OpenEmbedded. Follow these instructions to set up OpenEmbedded on your host computer and compile the net-tools recipe:

$ bitbake net-tools

Copy the generated .ipk packages to your board. They should be in deploy/ipk/armv7at2hf-neon.

$ scp deploy/ipk/armv7at2hf-neon/net-tools* root@<board-ip>:~

Then on your board:

# opkg install net-tools*

Setting up the network interface

With the ESP8266 connected, run the following command on your target board:

# slattach -p slip -s 115200 /dev/ttymx2&

This will attach the serial line device that is, in this example, on UART_C (mapped as /dev/ttymxc2, using the Colibri iMX6DL) with a baud rate of 115200 baud using the SLIP protocol.

Then run:

# ifconfig sl0 pointopoint up mtu 1500

This will create a new network interface (sl0) with address and Point-to-Point address These addresses are the default and can be altered on the user_config.h file in the firmware.

Now that the ESP8266 is working as a router, you can access its terminal by executing

# telnet 7777

If you configured your SSID and password on user_config.h previously, you can see that the ESP8266 is already connected to your wireless network by running

External IP:
DNS server:
Clock speed: 80
Serial bit rate: 115200

If you need to connect to another SSID and insert another password, you can run:

CMD> set ssid <NEW_SSID>
CMD> set password <NEW_PASSWORD>
CMD> save
CMD> reset

To be able to access the internet, you must add a route:

# route add default gw

And the DNS server that is shown when the show command was executed on the ESP8266 router terminal ( in this example):

# echo "nameserver" > /etc/resolv.conf

Now you should be able to connect to the internet. Test it by pinging any address:

root@colibri-imx6:~# ping
PING ( 56 data bytes
64 bytes from seq=0 ttl=47 time=273.141 ms
64 bytes from seq=1 ttl=47 time=204.406 ms
64 bytes from seq=2 ttl=47 time=166.225 ms
64 bytes from seq=3 ttl=47 time=161.818 ms
64 bytes from seq=4 ttl=47 time=159.971 ms
64 bytes from seq=5 ttl=47 time=158.016 ms
64 bytes from seq=6 ttl=47 time=156.343 ms
--- ping statistics ---
7 packets transmitted, 7 packets received, 0% packet loss
round-trip min/avg/max = 156.343/182.845/273.141 ms

Note that, since the UART is communicating at 115200 baud, the connection speed will be rather slow.

Using an ESP07 module on WinCE

It is really easy to interface these modules supporting UART (AT Commands) with any controller or processor.

Hardware Interface

Demo application in C (WinCE)

We have done an example application in C to connect the ESP07 WiFi module to network & receive data. The ESP07 module is configured as a server and Hercules is used as a client.

Download project