Building

This assumes you have the Toolchain set up. Note that compiling to support OTA upgrades is beyond the scope of this tutorial.

Compiling

Choose one of the examples to build. Either the AT demo, pre-programmed in a lot of devices, or the IoT demo included with the ESP IoT SDK.

The AT Demo

cd /opt/Espressif/ESP8266_SDK
wget -O at_v0.19_14_10_30.zip http://bbs.espressif.com/download/file.php?id=13
unzip at_v0.19_14_10_30.zip
cd at_v0.19_on_SDKv0.9.2
make

This should be enough before #Preparing the Firmware Image.

IoT Demo

cd /opt/Espressif/ESP8266_SDK/IoT_Demo
make

Preparing the Firmware Image

The following is encoded in app/gen_misc.sh, but we use the crosstool-NG binutils, and the paths are off-by-one, so we show it in full here. We also use esptool rather than genflashbinv6.exe to not require Windows.

cd .output/eagle/debug/image
esptool -eo eagle.app.v6.out -bo eagle.app.v6.flash.bin -bs .text -bs .data -bs .rodata -bc -ec
xtensa-lx106-elf-objcopy --only-section .irom0.text -O binary eagle.app.v6.out eagle.app.v6.irom0text.bin
cp eagle.app.v6.flash.bin ../../../../../bin/
cp eagle.app.v6.irom0text.bin ../../../../../bin/

Now you have two files in /opt/Espressif/ESP8266_SDK/bin/, one with the application code and data (called ...flash.bin) and one with SDK code (called ...irom0text.bin).

Move on to Uploading to a device.

More Examples

More examples, like Blinky, can be found on GitHub, https://github.com/esp8266/source-code-examples.