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This guide explains how to set up the development environment and create applications for ESP8266 on Linux systems (tested on Ubuntu 14.04).

Connecting ESP8266 to PC (Linux)

To connect the ESP8266 chip to PC, a 3.3V USB-to-TTL connector is required.

This section guides you through the connection process for the ESP8266-01 module, please refer to the ESP8266 documentation for information about other modules.

If you are going to connect ESP8266 in another way, make sure that the power source does not exceed ~3.6V

Flash mode

ESP8266USB-to-TTL
URXDTXD
UTXDRXD
CH_PD3.3V
GNDGND
VCC3.3V
GPIO0GND
GPIO23.3V

Run mode

ESP8266USB-to-TTL
URXDTXD
UTXDRXD
CH_PD3.3V
GNDGND
VCC3.3V

 

Installing required software

Before building the SDK for the ESP8266 platform, you need to install ESP8266 RTOS SDK, Xtensa GCC toolchain, and esptool.py utitlity for uploading firmware.

1. Install prerequisites:

2. Install ESP RTOS SDK:

3. Install Xtensa-lx106 GNU toolchain:

4. Install improved esptool.py:

Creating applications based on C SDK

Building C SDK

To build the C SDK for the ESP8266 platform, you will need to use GNU toolchain for Xtensa (which can be installed from sources as described above).

To create applications based on the C SDK, at first you should build a static library from the generated SDK. To do so, generate the C SDK in Admin UI, then extract the archive, cd to it and execute the following:

The C SDK will be installed to the <YOUR_DESTINATION_PATH> directory. For more details on building the C SDK, please refer to this page.

Tips & tricks

  • According to the ESP8266 SDK programming guide, the user application starts its execution in the user_init() function.
  • To make the Kaa SDK work, you should establish network connection through WiFi. For more details on WiFi configuration, please refer to the ESP8266 official documentation.
  • To see any output on the serial port, a UART driver is required. 

You can use ConfigurationDemo (available in Kaa Sandbox) as an example of the UART and WiFi functionality coupled together with the Kaa endpoint SDK.

Linker Script

The ESP SDK provides a set of linker scripts for different Flash configurations. However, to run a Kaa client, some modifications to those scripts are required.

Basically, there are two sections where code can be placed. The first one is the .text section, which maps to the iram segment, and another one is the .irom0.text section, which maps to the irom segment.

The issue is that there is not enough space to place the Kaa SDK code in the iram segment  (the .text section is mapped to the iram segment by default) . This is why the default SDK linker scripts are modified to force linking the Kaa SDK code to the irom segment.

You can find valid linker scripts in the ld directory of ConfigurationDemo for the ESP8266 platform.

Example

As an example, you can try out ConfigurationDemo. Put generated SDK from Kaa Sandbox into libs/kaa folder.

Connect ESP8266 to your PC through a USB-to-TTL connector as mentioned above, and execute the following in your terminal from demo root folder:

The deploy command of build.sh script builds the C SDK for the ESP8266 platform, builds the ConfigurationDemo itself and a platform-dependent glue code for ESP8266 (WiFi connectivity, a UART driver), creates firmware images (build/0x00000.bin and build/0x40000.bin) and, finally, writes these images to Flash at the corresponding addresses. You will be prompted of your WiFi station SSID and password, so that ESP8266 can connect to it.


Copyright © 2014-2015, CyberVision, Inc.

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4 Comments

  1. If https clone fails at,

    git clone https://github.com/RostakaGmfun/esptool.git 

    use:

    git clone [email protected]:RostakaGmfun/esptool.git

  2. could you please help me i have problem after

    ./ct-ng xtensa-lx106-elf
    ./ct-ng build
    I can not install and shows me error becuase it could not be find the C++ but i have C++
  3. Hi all,

    I have a question. It is mentioned in the 'Example' section that I will be prompted for SSID and password during deployment.

    But I prefer it to work other way. I want the end user to configure the SSID and password. Is there a way? Should the SSID and password get embedded in the firmware?

    Any help will be much appreciated.

    Thanks,

    Sudheer 

    1. I not sure that it is a right place to ask and answer questions.

      Nevertheless, you can modify application code and ask user for WiFi credentials.

       

      There are no limitations for it neither in Kaa, nor in ESP.

      Our sample applications shows simplest way possible and simplest way is to embed SSID and password during build.

       

      Regards,

      Max

       

      P.S.

      We offer a forum for technical (and often non-technical) Q&A:

      https://groups.google.com/forum/#!forum/kaaproject