mirror of https://github.com/jeelabs/esp-link.git
Thorsten von Eicken
9 years ago
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Building esp-link |
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================= |
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|
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Before you build esp-link, consider that you can download ready-made firmware images! |
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Just head over to the [release section](https://github.com/jeelabs/esp-link/releases) |
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and download the tgz archive. |
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|
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If you decide to build your own, there are a number of options: |
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- On linux x86 download the ready-built toolchain and patched SDK like the automated build does |
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and compile the firmware |
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- On linux use a docker image with the toolchain and the SDK to compile the firmware |
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- On linux download and build the toolchain, download and patch the SDK, then compile the firmware |
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- On windows use a docker image with the toolchain and the SDK to compile the firmware |
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- On windows install mingw, python, java, and a slew of other tools and then build the |
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firmware |
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|
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Once you have built the firmware you will want to flash it to your esp8266 module. |
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Assuming you already have esp-link running you can either go back to the initial flashing |
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via the serial port or you can use the over-the-air (i.e. Wifi) update method, which is faster |
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and more reliable (unless you have a non-booting version of esp-link). |
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The OTA flashing is described at the end of this page, |
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the serial flashing is described in [FLASHING.md](FLASHING.md). |
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|
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### Automated builds |
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|
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For every commit on github an automated build is made. This means that every branch, including |
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master, and every pull request always has an up-to-date build. These builds are made by Travis |
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using the instructions in `.travis.yml`, which basically consist of cloning the esp-link repo, |
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downloading the compiler toolchain, downloading the Espressif SDK, and running `make`. |
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If you're looking for how to build esp-link the travis instructions will always give you |
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accurate pointers to what to download. |
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|
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### Docker (linux or windows) |
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|
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The [esp-link docker image](https://hub.docker.com/r/jeelabs/esp-link/) contains all the |
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tools to build esp-link as well as the appropriate Espressif SDK. *It does not contain the |
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esp-link source code!*. You use the docker image just to build the firmware, you don't have |
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to do your editing in there. The steps are: |
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- clone the esp-link github repo |
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- checkout the branch or tag you want (for example the tag `v2.2.3` for that release) |
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- cd into the esp-link top directory |
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- run `make` in docker while mounting your esp-link directory into the container: |
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- linux: `docker run -v $PWD:/esp-link jeelabs/esp-link:latest` |
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- windows: `docker run -v c:\somepath\esp-link:/esp-link jeelabs/esp-link:latest`, |
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where `somepath` is the path to where you cloned esp-link, you probably end up with |
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something like `-v c:\Users\tve\source\esp-link:/esp-link` |
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- if you are not building esp-link `master` then read the release notes to see which version of |
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the Espressif SDK you need and use that as tag for the container image, such as |
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`jeelabs/esp-link:SDK2.0.0.p1`; you can see the list of available SDKs on |
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[dockerhub](https://hub.docker.com/r/jeelabs/esp-link/tags/)o |
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|
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Sample steps to build esp-link v2.2.3 on a Win7 Pro x64 (these use the docker terminal, there |
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are multiple way to skin the proverbial cat...): |
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1) Install Docker Toolbox ( http://www.docker.com/products/docker-toolbox ) |
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2) Install Git Desktop ( https://desktop.github.com/ ) |
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3) Clone esp-link from Github master to local repository ( https://github.com/jeelabs/esp-link ) |
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4) Open Docker Quickstart Terminal |
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5) cd to local esp-link git repository ( C:\Users\xxxxx\Documents\GitHub\esp-link ) |
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6) Run "docker run -v $PWD:/esp-link jeelabs/esp-link" command in Docker Quickstart Terminal window |
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|
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Note: there has been one report of messed-up timestamps on windows, the symptom is that `make` |
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complains about file modification times being in the future. This may be due to the different |
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way Windows and Linux handle time zones and daylight savings time. PLease report if you |
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encounter this or know a solution. |
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|
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### Linux |
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|
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The firmware has been built using the https://github.com/pfalcon/esp-open-sdk[esp-open-sdk] |
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on a Linux system. Create an esp8266 directory, install the esp-open-sdk into a sub-directory |
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using the *non-standalone* install (i.e., there should not be an sdk directory in the esp-open-sdk |
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dir when done installing, *if you use the standalone install you will get compilation errors* |
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with std types, such as `uint32_t`). |
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|
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Download the Espressif "NONOS" SDK (use the version mentioned in the release notes) from their |
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http://bbs.espressif.com/viewforum.php?f=5[download forum] and also expand it into a |
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sub-directory. Often there are patches to apply, in that case you need to download the patches |
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from the same source and apply them. |
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|
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You can simplify your life (and avoid the hour-long build time for esp-open-sdk) if you are |
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on an x86 box by downloading the packaged and built esp-open-sdk and the fully patches SDKfrom the |
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links used in the `.travis.yaml`. |
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|
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Clone the esp-link repository into a third sub-directory and check out the tag you would like, |
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such as `git checkout v2.2.3`. |
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This way the relative paths in the Makefile will work. |
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If you choose a different directory structure look at the top of the Makefile for the |
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appropriate environment variables to define. |
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Do not use the source tarballs from the release page on github, |
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these will give you trouble compiling because the Makefile uses git to determine the esp-link |
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version being built. |
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|
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In order to OTA-update the esp8266 you should `export ESP_HOSTNAME=...` with the hostname or |
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IP address of your module. |
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|
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Now, build the code: `make` in the top-level of esp-link. If you want to se the commands being |
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issued, use `VERBOSE=1 make`. |
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|
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A few notes from others (I can't fully verify these): |
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|
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- You may need to install `zlib1g-dev` and `python-serial` |
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- Make sure you have the correct version of the SDK |
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- Make sure the paths at the beginning of the makefile are correct |
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- Make sure `esp-open-sdk/xtensa-lx106-elf/bin` is in the PATH set in the Makefile |
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|
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### Windows |
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|
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Please consider installing docker and using the docker image to save yourself grief getting all |
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the tools installed and working. |
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If you do want to compile "natively" on Windows it certainly is possible. |
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|
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It is possible to build esp-link on Windows, but it requires a gaggle of software to be installed: |
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|
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- Install the unofficial sdk, mingw, SourceTree (gui git client), python 2.7, git cli, Java |
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- Use SourceTree to checkout under C:\espressif or wherever you installed the unofficial sdk, |
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(see this thread for the unofficial sdk http://www.esp8266.com/viewtopic.php?t=820) |
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- Create a symbolic link under c:/espressif for the git bin directory under program files and |
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the java bin directory under program files. |
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- ... |
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|
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## Updating the firmware over-the-air |
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|
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This firmware supports over-the-air (OTA) flashing, so you do not have to deal with serial |
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flashing again after the initial one! The recommended way to flash is to use `make wiflash` |
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if you are also building the firmware. |
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If you are downloading firmware binaries use `./wiflash`. |
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`make wiflash` assumes that you set `ESP_HOSTNAME` to the hostname or IP address of your esp-link. |
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You can easily do that using something like `ESP_HOSTNAME=192.168.1.5 make wiflash` or |
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`ESP_HOSTNAME=es-link.local make wiflash`. |
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|
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The flashing, restart, and re-associating with your wireless network takes about 15 seconds |
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and is fully automatic. The first 1MB of flash are divided into two 512KB partitions allowing for new |
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code to be uploaded into one partition while running from the other. This is the official |
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OTA upgrade method supported by the SDK, except that the firmware is POSTed to the module |
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using curl as opposed to having the module download it from a cloud server. On a module with |
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512KB flash there is only space for one partition and thus no way to do an OTA update. |
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|
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If you are downloading the prebuilt firmware image you will have both |
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`user1.bin` and `user2.bin` and run `wiflash.sh <esp-hostname> user1.bin user2.bin`. |
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This will query esp-link for which file it needs, upload the file, and then reconnect to |
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ensure all is well. |
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|
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Note that when you flash the firmware the wifi settings are all preserved so esp-link should |
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reconnect to your network within a few seconds and the whole flashing process should take 15-30 |
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from beginning to end. If you need to clear the wifi settings you need to reflash the `blank.bin` |
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using the serial port. |
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|
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The flash configuration and the OTA upgrade process is described in more detail |
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in [FLASH.md](FLASH.md). If OTA flashing doesn't work for you the serial flashing is described |
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in [FLASHING.md](FLASHING.md). |
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@ -0,0 +1,335 @@ |
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ESP-LINK: Wifi-Serial Bridge w/REST&MQTT |
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======================================== |
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|
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The esp-link firmware connects a micro-controller to the internet using an ESP8266 Wifi module. |
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It implements a number of features: |
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|
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- transparent bridge between Wifi and serial, useful for debugging or inputting into a uC |
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- flash-programming attached Arduino/AVR microcontrollers and |
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LPC800-series and other ARM microcontrollers via Wifi |
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- built-in stk500v1 programmer for AVR uC's: program using HTTP upload of hex file |
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- outbound REST HTTP requests from the attached micro-controller to the internet |
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- MQTT client pub/sub from the attached micro-controller to the internet |
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- serve custom web pages containing data that is dynamically pulled from the attached uC and |
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that contain buttons and fields that are transmitted to the attached uC (feature not |
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fully ready yet) |
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|
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The firmware includes a tiny HTTP server based on |
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http://www.esp8266.com/viewforum.php?f=34[esphttpd] |
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with a simple web interface, many thanks to Jeroen Domburg for making it available! |
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The REST and MQTT functionality are loosely based on https://github.com/tuanpmt/espduino |
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but significantly rewritten and no longer protocol compatible, thanks to tuanpmt for the |
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inspiration! |
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|
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Many thanks to https://github.com/brunnels[brunnels] for contributions in particular around |
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the espduino functionality. |
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Thanks to https://github.com/cskarai[cskarai] for the custom dynamic web page functionality |
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and to https://github.com/beegee-tokyo[beegee-tokyo] for lots of code documentation. |
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Thank you also to https://github.com/susisstrolch[susisstrolch] for the syslog feature, |
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https://github.com/bc547[bc547], and https://github.com/katast[katast] for |
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additional contributions. Esp-link is the work of many contributors! |
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|
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Note that http://github.com/jeelabs/esp-link is the original esp-link software which has |
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notably been forked by arduino.org as https://github.com/arduino-org/Esp-Link[Esp-Link] and shipped |
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with the initial Arduino Uno Wifi. The JeeLabs esp-link has evolved significantly since the |
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fork and added cool new features as well as bug fixes. |
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|
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### Quick links |
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|
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In this document: [goals](#esp-link-goals), [uses](#esp-link-uses), [eye candy](#eye-candy), |
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[getting-started](#getting-started), [contact](#contact). |
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Separate documents: [hardware configuration](), [serial flashing](), [troubleshooting](), |
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[over-the-air flashing](), [building esp-link](), [flash layout](), [serial bridge](), |
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[flashing an attached uC](), [MQTT and outbound REST requests](), [service web pages]() |
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|
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For quick support and questions chat at |
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image:https://badges.gitter.im/Join%20Chat.svg[link="https://gitter.im/jeelabs/esp-link"] |
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or (a little slower) open a github issue. |
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|
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Releases & Downloads |
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-------------------- |
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Esp-link uses semantic versioning. The main change between versions 1.x and 2.x was the |
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addition of MQTT and outbound REST requests from the attached uC. The main change between 2.x |
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and 3.x will be the addition of custom web pages (this is not ready yet). |
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|
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- The master branch is currently unstable as we integrate a number of new features to get |
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to version 3.0. Please use v2.2.3 unless you want to hack up the latest code! |
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This being said, the older functionality seems to work fine on master, YMMV... |
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- https://github.com/jeelabs/esp-link/releases/tag/v2.2.3[V2.2.3] is the most recent release. |
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It has a built-in stk500v1 programmer (for AVRs), work on all modules, and supports mDNS, |
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sNTP, and syslog. It is built using the Espressif SDK 1.5.4. |
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- https://github.com/jeelabs/esp-link/releases/tag/v2.1.7[V2.1.7] is the previous release. |
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- See https://github.com/jeelabs/esp-link/releases[all releases]. |
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|
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Intro |
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----- |
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|
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### Esp-link goals |
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|
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The goal of the esp-link project is to create an advanced Wifi co-processor. Esp-link assumes that |
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there is a "main processor" (also referred to as "attached uController") and that esp-link's role |
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is to facilitate communication over Wifi. This means that esp-link does not just connect TCP/UDP |
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sockets through to the attached uC, rather it implements mostly higher-level functionality to |
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offload the attached uC, which often has much less flash and memory than esp-link. |
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|
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Where esp-link is a bit unusual is that it's not really |
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just a Wifi interface or a slave co-processor. In some sense it's the master, because the main |
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processor can be reset, controlled and reprogrammed through esp-link. The three main areas of |
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functionality in esp-link are: |
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|
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- reprogramming and debugging the attached uC |
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- letting the attached uC make outbound communication and offloading the protocol processing |
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- forwarding inbound communication and offloading the protocol processing |
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|
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The goal of the project is also to remain focused on the above mission. In particular, esp-link |
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is not a platform for stand-alone applications and it does not support connecting sensors or |
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actuators directly to it. A few users have taken esp-link as a starting point for doing these |
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things and that's great, but there's also value in keeping the mainline esp-link project |
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focused on a clear mission. |
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|
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### Esp-link uses |
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|
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The simplest use of esp-link is as a transparent serial to wifi bridge. You can flash an attached |
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uC over wifi and you can watch the uC's serial debug output by connecting to port 23 or looking |
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at the uC Console web page. |
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|
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The next level is to use the outbound connectivity of esp-link in the uC code. For example, the |
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uC can use REST requests to services like thingspeak.com to send sensor values that then get |
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stored and plotted by the external service. |
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The uC can also use REST requests to retrieve simple configuration |
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information or push other forms of notifications. (MQTT functionality is forthcoming.) |
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|
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An additional option is to add code to esp-link to customize it and put all the communication |
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code into esp-link and only keep simple sensor/actuator control in the attached uC. In this |
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mode the attached uC sends custom commands to esp-link with sensor/acturator info and |
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registers a set of callbacks with esp-link that control sensors/actuators. This way, custom |
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commands in esp-link can receive MQTT messages, make simple callbacks into the uC to get sensor |
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values or change actuators, and then respond back with MQTT. The way this is architected is that |
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the attached uC registers callbacks at start-up such that the code in the esp doesn't need to |
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know which exact sensors/actuators the attached uC has, it learns that through the initial |
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callback registration. |
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|
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### Eye Candy |
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|
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These screen shots show the Home page, the Wifi configuration page, the console for the |
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attached microcontroller, and the pin assignments card: |
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|
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image:https://cloud.githubusercontent.com/assets/39480/8261425/6ca395a6-167f-11e5-8e92-77150371135a.png[width="45%"] |
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image:https://cloud.githubusercontent.com/assets/39480/8261427/6caf7326-167f-11e5-8085-bc8b20159b2b.png[width="45%"] |
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image:https://cloud.githubusercontent.com/assets/39480/8261426/6ca7f75e-167f-11e5-827d-9a1c582ad05d.png[width="45%"] |
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image:https://cloud.githubusercontent.com/assets/39480/8261658/11e6c64a-1681-11e5-82d0-ea5ec90a6ddb.png[width="45%"] |
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|
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Getting Started |
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--------------- |
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|
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To get started you need to: |
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1. prepare your esp8266 module for serial flashing |
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2. download the latest esp-link release image (you can build your own later) |
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3. flash the firmware |
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4. configure the Wifi in esp-link for your network |
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|
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You can then attach a uC and upload a sketch: |
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1. attach a uC (e.g. arduino) to your esp8266 module |
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2. connect via the serial port to see a pre-loaded sketch running |
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3. upload a fresh version of the sketch |
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|
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From there, more advanced steps are: |
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- write a sketch that uses MQTT to communicate, or that makes outbound REST requests |
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- create some web pages and write a sketch that populates data in them or reacts to buttons |
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and forms |
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- make changes or enhancements to esp-link and build your own firmware |
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|
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Serial bridge and connections to Arduino, AVR, ARM, LPC microcontrollers |
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------------------------------------------------------------------------ |
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|
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In order to connect through the esp-link to a microcontroller use port 23. For example, |
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on linux you can use `nc esp-hostname 23` or `telnet esp-hostname 23`. |
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|
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Note that multiple connections to port 23 and 2323 can be made simultaneously. Esp-link will |
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intermix characters received on all these connections onto the serial TX and it will |
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broadcast incoming characters from the serial RX to all connections. Use with caution! |
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|
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### Flashing an attached AVR/Arduino |
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|
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There are three options for reprogramming an attached AVR/Arduino microcontroller: |
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|
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- Use avrdude and point it at port 23 of esp-link. Esp-link automatically detects the programming |
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sequence and issues a reset to the AVR. |
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- Use avrdude and point it at port 2323 of esp-link. This is the same as port 23 except that the |
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autodectection is not used and the reset happens because port 2323 is used |
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- Use curl or a similar tool to HTTP POST the firmware to esp-link. This uses the built-in |
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programmer, which only works for AVRs/Arduinos with the optiboot bootloader (which is std). |
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|
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To reprogram an Arduino / AVR microcontroller by pointing avrdude at port 23 or 2323 you |
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specify a serial port of the form `net:esp-link:23` in avrdude's -P option, where |
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`esp-link` is either the hostname of your esp-link or its IP address). |
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This is instead of specifying a serial port of the form /dev/ttyUSB0. |
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Esp-link detects that avrdude starts its connection with a flash synchronization sequence |
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and sends a reset to the AVR microcontroller so it can switch into flash programming mode. |
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|
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To reprogram using the HTTP POST method you need to first issue a POST to put optiboot into |
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programming mode: POST to `http://esp-link/pgm/sync`, this starts the process. Then check that |
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synchronization with optiboot has been achieved by issuing a GET to the same URL |
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(`http://esp-link/pgm/sync`). Repeat until you have sync (takes <500ms normally). Finally |
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issue a POST request to `http://esp-link/pgm/upload` with your hex file as POST data (raw, |
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not url-encoded or multipart-mime. Please look into the avrflash script for the curl command-line |
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details or use that script directly (`./avrflash esp-link.local my_sketch.hex`). |
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_Important_: after the initial sync request that resets the AVR you have 10 seconds to get to the |
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upload post or esp-link will time-out. So if you're manually entering curl commands have them |
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prepared so you can copy&paste! |
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|
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Beware of the baud rate, which you can set on the uC Console page. Sometimes you may be using |
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115200 baud in sketches but the bootloader may use 57600 baud. When you use port 23 or 2323 you |
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need to set the baud rate correctly. If you use the built-in programmer (HTTP POST method) then |
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esp-link will try the configured baud rate and also 9600, 57600, and 115200 baud, so it should |
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work even if you have the wrong baud rate configured... |
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|
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When to use which method? If port 23 works then go with that. If you have trouble getting sync |
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or it craps out in the middle too often then try the built-in programmer with the HTTP POST. |
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If your AVR doesn't use optiboot then use port 2323 since esp-link may not recognize the programming |
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sequence and not issue a reset if you use port 23. |
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|
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If you are having trouble with the built-in programmer and see something like this: |
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|
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-------------------- |
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# ./avrflash 192.168.3.104 blink.hex |
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Error checking sync: FAILED to SYNC: abandoned after timeout, got: |
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:\xF/\x00\xCj\xCz\xCJ\xCZ\xC\xAÜ\xC\xAä\xC\xAÜ\xC\xAä\xC\xBì\xC\xBô\xC\xBì\xC\xBô\xC\xAÜ\xC\xAä\xC |
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-------------------- |
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|
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the most likely cause is a baud rate mismatch and/or a bad connection from the esp8266 to the |
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AVRs reset line. |
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The baud rate used by esp-link is set on the uC Console web page and, as mentioned above, it will |
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automatically try 9600, 57600, and 115200 as well. |
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The above garbage characters are most likely due to optiboot timing out and starting the sketch |
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and then the sketch sending data at a different baud rate than configured into esp-link. |
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Note that sketches don't necessarily use the same baud rate as optiboot, so you may have the |
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correct baud rate configured but reset isn't functioning, or reset may be functioning but the |
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baud rate may be incorrect. |
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|
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The output of a successful flash using the built-in programmer looks like this: |
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|
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-------------------- |
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Success. 3098 bytes at 57600 baud in 0.8s, 3674B/s 63% efficient |
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-------------------- |
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|
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This says that the sketch comprises 3098 bytes of flash, was written in 0.8 seconds |
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(excludes the initial sync time) at 57600 baud, |
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and the 3098 bytes were flashed at a rate of 3674 bytes per second. |
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The efficiency measure is the ratio of the actual rate to the serial baud rate, |
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thus 3674/5760 = 0.63 (there are 10 baud per character). |
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The efficiency is not 100% because there is protocol overhead (such as sync, record type, and |
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length characters) |
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and there is dead time waiting for an ack or preparing the next record to be sent. |
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|
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### Details of built-in AVR flash algorithm |
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|
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The built-in flashing algorithm differs a bit from what avrdude does. The programming protocol |
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states that STK_GET_SYNC+CRC_EOP (0x30 0x20) should be sent to synchronize, but that works poorly |
||||
because the AVR's UART only buffers one character. This means that if STK_GET_SYNC+CRC_EOP is |
||||
sent twice there is a high chance that only the last character (CRC_EOP) is actually |
||||
received. If that is followed by another STK_GET_SYNC+CRC_EOP sequence then optiboot receives |
||||
CRC_EOP+STK_GET_SYNC+CRC_EOP which causes it to abort and run the old sketch. Ending up in that |
||||
situation is quite likely because optiboot initializes the UART as one of the first things, but |
||||
then goes off an flashes an LED for ~300ms during which it doesn't empty the UART. |
||||
|
||||
Looking at the optiboot code, the good news is that CRC_EOP+CRC_EOP can be used to get an initial |
||||
response without the overrun danger of the normal sync sequence and this is what esp-link does. |
||||
The programming sequence runs as follows: |
||||
|
||||
- esp-link sends a brief reset pulse (1ms) |
||||
- esp-link sends CRC_EOP+CRC_EOP ~50ms later |
||||
- esp-link sends CRC_EOP+CRC_EOP every ~70-80ms |
||||
- eventually optiboot responds with STK_INSYNC+STK_OK (0x14;0x10) |
||||
- esp-link sends one CRC_EOP to sort out the even/odd issue |
||||
- either optiboot responds with STK_INSYNC+STK_OK or nothing happens for 70-80ms, in which case |
||||
esp-link sends another CRC_EOP |
||||
- esp-link sends STK_GET_SYNC+CRC_EOP and optiboot responds with STK_INSYNC+STK_OK and we're in |
||||
sync now |
||||
- esp-link sends the next command (starts with 'u') and programming starts... |
||||
|
||||
If no sync is achieved, esp-link changes baud rate and the whole thing starts over with a reset |
||||
pulse about 600ms, esp-link gives up after about 5 seconds and reports an error. |
||||
|
||||
### Flashing an attached ARM processor |
||||
|
||||
You can reprogram NXP's LPC800-series and many other ARM processors as well by pointing your |
||||
programmer similarly at the esp-link's port 23. For example, if you are using |
||||
https://github.com/jeelabs/embello/tree/master/tools/uploader a command line like |
||||
`uploader -t -s -w esp-link:23 build/firmware.bin` does the trick. |
||||
The way it works is that the uploader uses telnet protocol escape sequences in order to |
||||
make esp-link issue the appropriate "ISP" and reset sequence to the microcontroller to start the |
||||
flash programming. If you use a different ARM programming tool it will work as well as long as |
||||
it starts the connection with the `?\r\n` synchronization sequence. |
||||
|
||||
### Flashing an attached esp8266 |
||||
|
||||
Yes, you can use esp-link running on one esp8266 module to flash another esp8266 module, |
||||
however it is rather tricky! The problem is not electric, it is wifi interference. |
||||
The basic idea is to use some method to direct the esp8266 flash program to port 2323 of |
||||
esp-link. Using port 2323 with the appropriate wiring will cause the esp8266's reset and |
||||
gpio0 pins to be toggled such that the chip enters the flash programming mode. |
||||
|
||||
One option for connecting the programmer with esp-link is to use my version of esptool.py |
||||
at http://github.com/tve/esptool, which supports specifying a URL instead of a port. Thus |
||||
instead of specifying something like `--port /dev/ttyUSB0` or `--port COM1` you specify |
||||
`--port socket://esp-link.local:2323`. Important: the baud rate specified on the esptool.py |
||||
command-line is irrelevant as the baud rate used by esp-link will be the one set in the |
||||
uC console page. Fortunately the esp8266 bootloader does auto-baud detection. (Setting the |
||||
baud rate to 115200 is recommended.) |
||||
|
||||
Another option is to use a serial-to-tcp port forwarding driver and point that to port 2323 |
||||
of esp-link. On windows users have reported success with |
||||
http://www.hw-group.com/products/hw_vsp/hw_vsp2_en.html[HW Virtual Serial Port] |
||||
|
||||
Now to the interference problem: once the attached esp8266 is reset it |
||||
starts outputting its 26Mhz clock on gpio0, which needs to be attached to |
||||
the esp8266 running esp-link (since it needs to drive gpio0 low during |
||||
the reset to enter flash mode). This 26Mhz signal on gpio0 causes a |
||||
significant amount of radio interference with the result that the esp8266 |
||||
running esp-link has trouble receiving Wifi packets. You can observe this |
||||
by running a ping to esp-link in another window: as soon as the target |
||||
esp8266 is reset, the pings become very slow or stop altogetehr. As soon |
||||
as you remove power to the attached esp8266 the pings resume beautifully. |
||||
|
||||
To try and get the interference under control, try some of the following: |
||||
add a series 100ohm resistor and 100pf capacitor to ground as close to |
||||
the gpio0 pin as possible (basically a low pass filter); and/or pass |
||||
the cable connecting the two esp8266's through a ferrite bead. |
||||
|
||||
### Debug log |
||||
|
||||
The esp-link web UI can display the esp-link debug log (os_printf statements in the code). This |
||||
is handy but sometimes not sufficient. Esp-link also prints the debug info to the UART where |
||||
it is sometimes more convenient and sometimes less... For this reason three UART debug log |
||||
modes are supported that can be set in the web UI (and the mode is saved in flash): |
||||
|
||||
- auto: the UART log starts enabled at boot using uart0 and disables itself when esp-link |
||||
associates with an AP. It re-enables itself if the association is lost. |
||||
- off: the UART log is always off |
||||
- on0: the UART log is always on using uart0 |
||||
- on1: the UART log is always on using uart1 (gpio2 pin) |
||||
|
||||
Note that even if the UART log is always off the ROM prints to uart0 whenever the |
||||
esp8266 comes out of reset. This cannot be disabled. |
||||
|
||||
Outbound HTTP REST requests and MQTT client |
||||
------------------------------------------- |
||||
|
||||
The V2 versions of esp-link use the SLIP protocol over the serial link to support simple outbound |
||||
HTTP REST requests as well as an MQTT client. The SLIP protocol consists of commands with |
||||
binary arguments sent from the |
||||
attached microcontroller to the esp8266, which then performs the command and responds back. |
||||
The responses back use a callback address in the attached microcontroller code, i.e., the |
||||
command sent by the uC contains a callback address and the response from the esp8266 starts |
||||
with that callback address. This enables asynchronous communication where esp-link can notify the |
||||
uC when requests complete or when other actions happen, such as wifi connectivity status changes. |
||||
|
||||
You can find REST and MQTT libraries as well as demo sketches in the |
||||
https://github.com/jeelabs/el-client[el-client] repository. |
||||
|
||||
Contact |
||||
------- |
||||
|
||||
If you find problems with esp-link, please create a github issue. If you have a question, please |
||||
use the gitter chat link at the top of this page. |
||||
@ -0,0 +1,14 @@ |
||||
Outbound HTTP REST requests and MQTT client |
||||
------------------------------------------- |
||||
|
||||
The V2 versions of esp-link use the SLIP protocol over the serial link to support simple outbound |
||||
HTTP REST requests as well as an MQTT client. The SLIP protocol consists of commands with |
||||
binary arguments sent from the |
||||
attached microcontroller to the esp8266, which then performs the command and responds back. |
||||
The responses back use a callback address in the attached microcontroller code, i.e., the |
||||
command sent by the uC contains a callback address and the response from the esp8266 starts |
||||
with that callback address. This enables asynchronous communication where esp-link can notify the |
||||
uC when requests complete or when other actions happen, such as wifi connectivity status changes. |
||||
|
||||
You can find REST and MQTT libraries as well as demo sketches in the |
||||
https://github.com/jeelabs/el-client[el-client] repository. |
||||
@ -0,0 +1,177 @@ |
||||
Flashing an attached Microcontroller |
||||
==================================== |
||||
|
||||
In order to connect through the esp-link to a microcontroller use port 23. For example, |
||||
on linux you can use `nc esp-hostname 23` or `telnet esp-hostname 23`. |
||||
|
||||
Note that multiple connections to port 23 and 2323 can be made simultaneously. Esp-link will |
||||
intermix characters received on all these connections onto the serial TX and it will |
||||
broadcast incoming characters from the serial RX to all connections. Use with caution! |
||||
|
||||
### Flashing an attached AVR/Arduino |
||||
|
||||
There are three options for reprogramming an attached AVR/Arduino microcontroller: |
||||
|
||||
- Use avrdude and point it at port 23 of esp-link. Esp-link automatically detects the programming |
||||
sequence and issues a reset to the AVR. |
||||
- Use avrdude and point it at port 2323 of esp-link. This is the same as port 23 except that the |
||||
autodectection is not used and the reset happens because port 2323 is used |
||||
- Use curl or a similar tool to HTTP POST the firmware to esp-link. This uses the built-in |
||||
programmer, which only works for AVRs/Arduinos with the optiboot bootloader (which is std). |
||||
|
||||
To reprogram an Arduino / AVR microcontroller by pointing avrdude at port 23 or 2323 you |
||||
specify a serial port of the form `net:esp-link:23` in avrdude's -P option, where |
||||
`esp-link` is either the hostname of your esp-link or its IP address). |
||||
This is instead of specifying a serial port of the form /dev/ttyUSB0. |
||||
Esp-link detects that avrdude starts its connection with a flash synchronization sequence |
||||
and sends a reset to the AVR microcontroller so it can switch into flash programming mode. |
||||
|
||||
To reprogram using the HTTP POST method you need to first issue a POST to put optiboot into |
||||
programming mode: POST to `http://esp-link/pgm/sync`, this starts the process. Then check that |
||||
synchronization with optiboot has been achieved by issuing a GET to the same URL |
||||
(`http://esp-link/pgm/sync`). Repeat until you have sync (takes <500ms normally). Finally |
||||
issue a POST request to `http://esp-link/pgm/upload` with your hex file as POST data (raw, |
||||
not url-encoded or multipart-mime. Please look into the avrflash script for the curl command-line |
||||
details or use that script directly (`./avrflash esp-link.local my_sketch.hex`). |
||||
_Important_: after the initial sync request that resets the AVR you have 10 seconds to get to the |
||||
upload post or esp-link will time-out. So if you're manually entering curl commands have them |
||||
prepared so you can copy&paste! |
||||
|
||||
Beware of the baud rate, which you can set on the uC Console page. Sometimes you may be using |
||||
115200 baud in sketches but the bootloader may use 57600 baud. When you use port 23 or 2323 you |
||||
need to set the baud rate correctly. If you use the built-in programmer (HTTP POST method) then |
||||
esp-link will try the configured baud rate and also 9600, 57600, and 115200 baud, so it should |
||||
work even if you have the wrong baud rate configured... |
||||
|
||||
When to use which method? If port 23 works then go with that. If you have trouble getting sync |
||||
or it craps out in the middle too often then try the built-in programmer with the HTTP POST. |
||||
If your AVR doesn't use optiboot then use port 2323 since esp-link may not recognize the programming |
||||
sequence and not issue a reset if you use port 23. |
||||
|
||||
If you are having trouble with the built-in programmer and see something like this: |
||||
|
||||
-------------------- |
||||
# ./avrflash 192.168.3.104 blink.hex |
||||
Error checking sync: FAILED to SYNC: abandoned after timeout, got: |
||||
:\xF/\x00\xCj\xCz\xCJ\xCZ\xC\xAÜ\xC\xAä\xC\xAÜ\xC\xAä\xC\xBì\xC\xBô\xC\xBì\xC\xBô\xC\xAÜ\xC\xAä\xC |
||||
-------------------- |
||||
|
||||
the most likely cause is a baud rate mismatch and/or a bad connection from the esp8266 to the |
||||
AVRs reset line. |
||||
The baud rate used by esp-link is set on the uC Console web page and, as mentioned above, it will |
||||
automatically try 9600, 57600, and 115200 as well. |
||||
The above garbage characters are most likely due to optiboot timing out and starting the sketch |
||||
and then the sketch sending data at a different baud rate than configured into esp-link. |
||||
Note that sketches don't necessarily use the same baud rate as optiboot, so you may have the |
||||
correct baud rate configured but reset isn't functioning, or reset may be functioning but the |
||||
baud rate may be incorrect. |
||||
|
||||
The output of a successful flash using the built-in programmer looks like this: |
||||
|
||||
-------------------- |
||||
Success. 3098 bytes at 57600 baud in 0.8s, 3674B/s 63% efficient |
||||
-------------------- |
||||
|
||||
This says that the sketch comprises 3098 bytes of flash, was written in 0.8 seconds |
||||
(excludes the initial sync time) at 57600 baud, |
||||
and the 3098 bytes were flashed at a rate of 3674 bytes per second. |
||||
The efficiency measure is the ratio of the actual rate to the serial baud rate, |
||||
thus 3674/5760 = 0.63 (there are 10 baud per character). |
||||
The efficiency is not 100% because there is protocol overhead (such as sync, record type, and |
||||
length characters) |
||||
and there is dead time waiting for an ack or preparing the next record to be sent. |
||||
|
||||
### Details of built-in AVR flash algorithm |
||||
|
||||
The built-in flashing algorithm differs a bit from what avrdude does. The programming protocol |
||||
states that STK_GET_SYNC+CRC_EOP (0x30 0x20) should be sent to synchronize, but that works poorly |
||||
because the AVR's UART only buffers one character. This means that if STK_GET_SYNC+CRC_EOP is |
||||
sent twice there is a high chance that only the last character (CRC_EOP) is actually |
||||
received. If that is followed by another STK_GET_SYNC+CRC_EOP sequence then optiboot receives |
||||
CRC_EOP+STK_GET_SYNC+CRC_EOP which causes it to abort and run the old sketch. Ending up in that |
||||
situation is quite likely because optiboot initializes the UART as one of the first things, but |
||||
then goes off an flashes an LED for ~300ms during which it doesn't empty the UART. |
||||
|
||||
Looking at the optiboot code, the good news is that CRC_EOP+CRC_EOP can be used to get an initial |
||||
response without the overrun danger of the normal sync sequence and this is what esp-link does. |
||||
The programming sequence runs as follows: |
||||
|
||||
- esp-link sends a brief reset pulse (1ms) |
||||
- esp-link sends CRC_EOP+CRC_EOP ~50ms later |
||||
- esp-link sends CRC_EOP+CRC_EOP every ~70-80ms |
||||
- eventually optiboot responds with STK_INSYNC+STK_OK (0x14;0x10) |
||||
- esp-link sends one CRC_EOP to sort out the even/odd issue |
||||
- either optiboot responds with STK_INSYNC+STK_OK or nothing happens for 70-80ms, in which case |
||||
esp-link sends another CRC_EOP |
||||
- esp-link sends STK_GET_SYNC+CRC_EOP and optiboot responds with STK_INSYNC+STK_OK and we're in |
||||
sync now |
||||
- esp-link sends the next command (starts with 'u') and programming starts... |
||||
|
||||
If no sync is achieved, esp-link changes baud rate and the whole thing starts over with a reset |
||||
pulse about 600ms, esp-link gives up after about 5 seconds and reports an error. |
||||
|
||||
### Flashing an attached ARM processor |
||||
|
||||
You can reprogram NXP's LPC800-series and many other ARM processors as well by pointing your |
||||
programmer similarly at the esp-link's port 23. For example, if you are using |
||||
https://github.com/jeelabs/embello/tree/master/tools/uploader a command line like |
||||
`uploader -t -s -w esp-link:23 build/firmware.bin` does the trick. |
||||
The way it works is that the uploader uses telnet protocol escape sequences in order to |
||||
make esp-link issue the appropriate "ISP" and reset sequence to the microcontroller to start the |
||||
flash programming. If you use a different ARM programming tool it will work as well as long as |
||||
it starts the connection with the `?\r\n` synchronization sequence. |
||||
|
||||
### Flashing an attached esp8266 |
||||
|
||||
__Flashing another esp8266 module is possible in theory but real-world attempts haveso far been |
||||
rather unsuccessful due to Wifi interference. This section is left here in case someone else |
||||
wants to dig in and find a solution.__ |
||||
|
||||
You can use esp-link running on one esp8266 module to flash another esp8266 module, |
||||
however it is rather tricky! The problem is not electric, it is wifi interference. |
||||
The basic idea is to use some method to direct the esp8266 flash program to port 2323 of |
||||
esp-link. Using port 2323 with the appropriate wiring will cause the esp8266's reset and |
||||
gpio0 pins to be toggled such that the chip enters the flash programming mode. |
||||
|
||||
One option for connecting the programmer with esp-link is to use my version of esptool.py |
||||
at http://github.com/tve/esptool, which supports specifying a URL instead of a port. Thus |
||||
instead of specifying something like `--port /dev/ttyUSB0` or `--port COM1` you specify |
||||
`--port socket://esp-link.local:2323`. Important: the baud rate specified on the esptool.py |
||||
command-line is irrelevant as the baud rate used by esp-link will be the one set in the |
||||
uC console page. Fortunately the esp8266 bootloader does auto-baud detection. (Setting the |
||||
baud rate to 115200 is recommended.) |
||||
|
||||
Another option is to use a serial-to-tcp port forwarding driver and point that to port 2323 |
||||
of esp-link. On windows users have reported success with |
||||
http://www.hw-group.com/products/hw_vsp/hw_vsp2_en.html[HW Virtual Serial Port] |
||||
|
||||
Now to the interference problem: once the attached esp8266 is reset it |
||||
starts outputting its 26Mhz clock on gpio0, which needs to be attached to |
||||
the esp8266 running esp-link (since it needs to drive gpio0 low during |
||||
the reset to enter flash mode). This 26Mhz signal on gpio0 causes a |
||||
significant amount of radio interference with the result that the esp8266 |
||||
running esp-link has trouble receiving Wifi packets. You can observe this |
||||
by running a ping to esp-link in another window: as soon as the target |
||||
esp8266 is reset, the pings become very slow or stop altogetehr. As soon |
||||
as you remove power to the attached esp8266 the pings resume beautifully. |
||||
|
||||
To try and get the interference under control, try some of the following: |
||||
add a series 100ohm resistor and 100pf capacitor to ground as close to |
||||
the gpio0 pin as possible (basically a low pass filter); and/or pass |
||||
the cable connecting the two esp8266's through a ferrite bead. |
||||
|
||||
### Debug log |
||||
|
||||
The esp-link web UI can display the esp-link debug log (os_printf statements in the code). This |
||||
is handy but sometimes not sufficient. Esp-link also prints the debug info to the UART where |
||||
it is sometimes more convenient and sometimes less... For this reason three UART debug log |
||||
modes are supported that can be set in the web UI (and the mode is saved in flash): |
||||
|
||||
- auto: the UART log starts enabled at boot using uart0 and disables itself when esp-link |
||||
associates with an AP. It re-enables itself if the association is lost. |
||||
- off: the UART log is always off |
||||
- on0: the UART log is always on using uart0 |
||||
- on1: the UART log is always on using uart1 (gpio2 pin) |
||||
|
||||
Note that even if the UART log is always off the ROM prints to uart0 whenever the |
||||
esp8266 comes out of reset. This cannot be disabled. |
||||
Loading…
Reference in new issue