* Move to PROGMEM aware libc, allow PSTR in printf() A Newlib (libc) patch is in progress to move the _P functions from inside Arduino into first-class citizens in libc. This Arduino patch cleans up code that's been migrated there. Binaries for the new libs are included because it seems they're part of the Arduino git tree, and should be replaced with @igrr built ones when/if the Newlib changes are accepted. Notable changes/additions for Arduino: Allow for use of PROGMEM based format and parameter strings in all *printf functions. No need for copying PSTR()s into RAM before printing them out (transparently saves heap space when using _P functions) and makes it easier to print out constant strings for applications. Add "%S" (capital-S) format that I've been told, but cannot verify, is used in Arduino to specify a PROGMEM string parameter in printfs, as an alias for "%s" since plain "%s" can now handle PROGMEM. Optimized the memcpy_P, strnlen_P, and strncpy_P functions to use 32-bit direct reads whenver possible (source and dest alignment mediated), but there is still room for improvement in others. Finally, move several constant arrays from RODATA into PROGMEM and update their accessors. Among these are the ctype array, ~260 bytes, mprec* arrays, ~300 bytes, and strings/daycounts in the time formatting functions, ~200 bytes. All told, sketches will see from 300 to 800 additional RAM heap free on startup (depending on their use of these routines). * Fix merge error in #ifdef/#endif * Fix host test using the newlib generic pgmspace.h Host tests now use the sys/pgmspace.h for compiles instead of the ESP8266-specific version. * Update with rebuilt libraries using latest newlib * Include binaries built directly from @igrr repo Rebuild the binaries using a git clone of https://github.com/igrr/newlib-xtensa Build commands for posterity: ```` rm -rf ./xtensa-lx106-elf/ ./configure --prefix=<DIR>/esp8266/tools/sdk/libc --with-newlib \ --enable-multilib --disable-newlib-io-c99-formats \ --disable-newlib-supplied-syscalls \ --enable-newlib-nano-formatted-io --enable-newlib-reent-small \ --enable-target-optspace \ --program-transform-name="s&^&xtensa-lx106-elf-&" \ --disable-option-checking --with-target-subdir=xtensa-lx106-elf \ --target=xtensa-lx106-elf rm -f etc/config.cache CROSS_CFLAGS="-fno-omit-frame-pointer -DSIGNAL_PROVIDED -DABORT_PROVIDED"\ " -DMALLOC_PROVIDED" \ PATH=<DIR>/esp8266/tools/xtensa-lx106-elf/bin/:$PATH \ make all install ```` * Fix merge define conflict in c_types.h * Fix strlen_P misaligned source error Include fix from newlib-xtensa/fix-strlen branch cleaning up misaligned access on a non-aligned source string. * Fix strlen_P and strcpy_P edge cases Ran the included test suite on ESP8266 tstring.c with the following defines: #define MAX_1 50 #define memcmp memcmp_P #define memcpy memcpy_P #define memmem memmem_P #define memchr memchr_P #define strcat strcat_P #define strncat strncat_P #define strcpy strcpy_P #define strlen strlen_P #define strnlen strnlen_P #define strcmp strcmp_P #define strncmp strncmp_P Uncovered edge case and return value problems in the optimized versions of the strnlen_P and strncpy_P functions. Corrected. * Fix memcpy_P return value memcpy-1.c test suite showed error in return value of memcpy_P. Correct it. * Fix strnlen_P/strlen_P off-by-4 error Random crashes, often on String constructors using a PSTR, would occur due to the accelerated strnlen_P going past the end of the string. Would make debug builds fail, too (ESP.getVersionString() failure). Fix to fall through to normal copy on a word that's got a 0 byte anywhere in it. * Add device tests for libc functional verification Add test suite used to debug libc optimized _P functions to the device tests. * Rebuild from igrr's repo (same source as prior) Rebuild .a from igrr's repo at 347260af117b4177389e69fd4d04169b11d87a97 * WIP - add exceptions * Fix exception to have 0-terminator * Move some exception constants to TEXT from RODATA * Remove throw stubs * Move more exception stuff to ROM * Enable exceptions in platform.io * Remove atexit, is duplicated in rebuilt lib Need to look at the quick-toolchain options, there seems to be a definition for atexit defined there (libgcc?) that needs to be excised. For now, remove our local do-nothing copy. * Update libgcc to remove soft-fp functions The esp-quick-toolchain generated libgcc.a needed to have the soft-FP routines that are in ROM removed from it. Remove them in the new esp-quick-toolchain and update. * Fix merge typos in Makefile * Add unhandled exception handler to postmortem * Return our atexit() handler * Latest stdc++, minimize exception emercengy area * Remove atexit from newlib atexit was defined in newlib strongly, but we also define a noop atexit in core. Since we never exit, use the core's noop and delete the atexit from libc.a Updated in esp-quick-toolchain as well. * Move __FUNCTION__ static strings to PROGMEM __FUNCTION__ is unlikely to be a timing sensitive variable, so move it to PROGMEM and not RODATA (RAM) using linker magic. asserts() now should take no RAM for any strings. * Clean up linker file, update to latest stdc++ * Update to latest stdc++ which doesn't call strerror * Update to GCC5.1 exception emergency allocator Using GCC 5.1's emergency memory allocator for exceptions, much less space is required in programs which do not use exceptions and when space is allocated it is managed more efficiently. * Initial try with new compiler toolchain * Include newlib built from esp-quick-toolchain * Update JSON with all new esp-quick-toolchain builds * Use 64bit Windows compiler on 64bit Windows * Dump std::exception.what() when possible When doing the panic on unhandled exceptions, try and grab the .what() pointer and dump it as part of the termination info. Makes it easy to see mem errors (std::bad_alloc) or std::runtime_error strings. * Use scripted install from esp-quick-toolchain Makes sure proper libraries and includes are present by using a scripted installation from esp-quick-install instead of a manual one. * Update eqk to remove atexit, fix packaging diff
Arduino core for ESP8266 WiFi chip
Quick links
Arduino on ESP8266
This project brings support for ESP8266 chip to the Arduino environment. It lets you write sketches using familiar Arduino functions and libraries, and run them directly on ESP8266, no external microcontroller required.
ESP8266 Arduino core comes with libraries to communicate over WiFi using TCP and UDP, set up HTTP, mDNS, SSDP, and DNS servers, do OTA updates, use a file system in flash memory, work with SD cards, servos, SPI and I2C peripherals.
Contents
- Installing options:
- Documentation
- Issues and support
- Contributing
- License and credits
Installing with Boards Manager
Starting with 1.6.4, Arduino allows installation of third-party platform packages using Boards Manager. We have packages available for Windows, Mac OS, and Linux (32 and 64 bit).
- Install the current upstream Arduino IDE at the 1.8 level or later. The current version is at the Arduino website.
- Start Arduino and open Preferences window.
- Enter
http://arduino.esp8266.com/stable/package_esp8266com_index.json
into Additional Board Manager URLs field. You can add multiple URLs, separating them with commas. - Open Boards Manager from Tools > Board menu and install esp8266 platform (and don't forget to select your ESP8266 board from Tools > Board menu after installation).
Latest release 
Boards manager link: http://arduino.esp8266.com/stable/package_esp8266com_index.json
Documentation: https://arduino-esp8266.readthedocs.io/en/2.4.2/
Using git version (basic instructions)
- Install the current upstream Arduino IDE at the 1.8 level or later. The current version is at the Arduino website.
- Go to Arduino directory
- For Mac OS X, it is
Arduino.app
showing as the Arduino icon.
This location may be your~/Downloads
,~/Desktop
or even/Applications
.cd <application-directory>/Arduino.app/Contents/Java
- For Linux, it is ~/arduino by default.
cd ~arduino
- For Mac OS X, it is
- Clone this repository into hardware/esp8266com/esp8266 directory (or clone it elsewhere and create a symlink)
cd hardware
mkdir esp8266com
cd esp8266com
git clone https://github.com/esp8266/Arduino.git esp8266
- Download binary tools (you need Python 2.7)
cd esp8266/tools
python get.py
- Restart Arduino
Using PlatformIO
PlatformIO is an open source ecosystem for IoT development with cross platform build system, library manager and full support for Espressif (ESP8266) development. It works on the popular host OS: macOS, Windows, Linux 32/64, Linux ARM (like Raspberry Pi, BeagleBone, CubieBoard).
- What is PlatformIO?
- PlatformIO IDE
- PlatformIO Core (command line tool)
- Advanced usage - custom settings, uploading to SPIFFS, Over-the-Air (OTA), staging version
- Integration with Cloud and Standalone IDEs - Cloud9, Codeanywhere, Eclipse Che (Codenvy), Atom, CLion, Eclipse, Emacs, NetBeans, Qt Creator, Sublime Text, VIM, Visual Studio, and VSCode
- Project Examples
Building with make
makeEspArduino is a generic makefile for any ESP8266 Arduino project. Using make instead of the Arduino IDE makes it easier to do automated and production builds.
Documentation
Documentation for latest development version: https://arduino-esp8266.readthedocs.io/en/latest/
Issues and support
ESP8266 Community Forum is a well established community for questions and answers about Arduino for ESP8266.
If you find this forum useful, please consider supporting it with a donation.
If you encounter an issue which you think is a bug in the ESP8266 Arduino Core or the associated libraries, you are welcome to submit it here on Github: https://github.com/esp8266/Arduino/issues.
Please provide as much context as possible:
- ESP8266 Arduino core version which you are using (you can check it in Boards Manager)
- your sketch code; please wrap it into a code block, see Github markdown manual
- when encountering an issue which happens at run time, attach serial output. Wrap it into a code block, just like the code.
- for issues which happen at compile time, enable verbose compiler output in the IDE preferences, and attach that output (also inside a code block)
- ESP8266 development board model
- IDE settings (board choich, flash size)
Contributing
For minor fixes of code and documentation, please go ahead and submit a pull request.
Check out the list of issues which are easy to fix — easy issues for 2.5.0. Working on them is a great way to move the project forward.
Larger changes (rewriting parts of existing code from scratch, adding new functions to the core, adding new libraries) should generally be discussed by opening an issue first.
Feature branches with lots of small commits (especially titled "oops", "fix typo", "forgot to add file", etc.) should be squashed before opening a pull request. At the same time, please refrain from putting multiple unrelated changes into a single pull request.
License and credits
Arduino IDE is developed and maintained by the Arduino team. The IDE is licensed under GPL.
ESP8266 core includes an xtensa gcc toolchain, which is also under GPL.
Esptool written by Christian Klippel is licensed under GPLv2, currently maintained by Ivan Grokhotkov: https://github.com/igrr/esptool-ck.
Espressif SDK included in this build is under Espressif MIT License.
ESP8266 core files are licensed under LGPL.
SPI Flash File System (SPIFFS) written by Peter Andersson is used in this project. It is distributed under MIT license.
umm_malloc memory management library written by Ralph Hempel is used in this project. It is distributed under MIT license.
axTLS library written by Cameron Rich, built from https://github.com/igrr/axtls-8266, is used in this project. It is distributed under BSD license.
BearSSL library written by Thomas Pornin, built from https://github.com/earlephilhower/bearssl-esp8266, is used in this project. It is distributed under the MIT License.