mirror of https://github.com/jeelabs/esp-link.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
280 lines
16 KiB
280 lines
16 KiB
ESP-LINK
|
|
========
|
|
|
|
This firmware connects an attached micro-controller to the internet using a ESP8266 Wifi module.
|
|
It implements a number of features:
|
|
- transparent bridge between Wifi and serial, useful for debugging or inputting into a uC
|
|
- flash-programming attached Arduino/AVR microcontrollers as well as LPC800-series and other
|
|
ARM microcontrollers via Wifi
|
|
- outbound TCP (and thus HTTP) connections from the attached micro-controller to the internet
|
|
- outbound REST HTTP requests from the attached micro-controller to the internet, protocol
|
|
based on espduino and compatible with [tuanpmt/espduino](https://github.com/tuanpmt/espduino)
|
|
|
|
The firmware includes a tiny HTTP server based on
|
|
[esphttpd](http://www.esp8266.com/viewforum.php?f=34)
|
|
with a simple web interface, many thanks to Jeroen Domburg for making it available!
|
|
Many thanks to https://github.com/brunnels for contributions around the espduino functionality.
|
|
|
|
###[Releases](https://github.com/jeelabs/esp-link/releases)
|
|
|
|
- [V2.0.beta2](https://github.com/jeelabs/esp-link/releases/tag/v2.0.beta2) has REST support but
|
|
requires a 1MByte or 4MByte ESP8266 flash, e.g. esp-12 or wroom-02
|
|
- [V1.0.1](https://github.com/jeelabs/esp-link/releases/tag/v1.0.1) is _stable_
|
|
and has the web server, transparent bridge, flash-programming support, but lacks
|
|
the REST and upcoming MQTT support. V1 works with 512KB flash, e.g. esp-1, esp-3, ...
|
|
|
|
For quick support and questions:
|
|
[](https://gitter.im/jeelabs/esp-link?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
|
|
|
|
Esp-link uses
|
|
-------------
|
|
The simplest use of esp-link is as a transparent serial to wifi bridge. You can flash an attached
|
|
uC over wifi and you can watch the uC's serial debug output by connecting to port 23 or looking
|
|
at the uC Console web page.
|
|
|
|
The next level is to use the outbound connectivity of esp-link in the uC code. For example, the
|
|
uC can use REST requests to services like thingspeak.com to send sensor values that then get
|
|
stored and plotted by the external service.
|
|
The uC can also use REST requests to retrieve simple configuration
|
|
information or push other forms of notifications. (MQTT functionality is forthcoming.)
|
|
|
|
An additional option is to add code to esp-link to customize it and put all the communication
|
|
code into esp-link and only keep simple sensor/actuator control in the attached uC. In this
|
|
mode the attached uC sends custom commands to esp-link with sensor/acturator info and
|
|
registers a set of callbacks with esp-link that control sensors/actuators. This way, custom
|
|
commands in esp-link can receive MQTT messages, make simple callbacks into the uC to get sensor
|
|
values or change actuators, and then respond back with MQTT. The way this is architected is that
|
|
the attached uC registers callbacks at start-up such that the code in the esp doesn't need to
|
|
know which exact sensors/actuators the attached uC has, it learns that through the initial
|
|
callback registration.
|
|
|
|
Eye Candy
|
|
---------
|
|
These screen shots show the Home page, the Wifi configuration page, the console for the
|
|
attached microcontroller, and the pin assignments card:
|
|
|
|
<img width="45%" src="https://cloud.githubusercontent.com/assets/39480/8261425/6ca395a6-167f-11e5-8e92-77150371135a.png">
|
|
<img width="45%" src="https://cloud.githubusercontent.com/assets/39480/8261427/6caf7326-167f-11e5-8085-bc8b20159b2b.png">
|
|
<img width="45%" src="https://cloud.githubusercontent.com/assets/39480/8261426/6ca7f75e-167f-11e5-827d-9a1c582ad05d.png">
|
|
<img width="30%" src="https://cloud.githubusercontent.com/assets/39480/8261658/11e6c64a-1681-11e5-82d0-ea5ec90a6ddb.png">
|
|
|
|
Hardware info
|
|
-------------
|
|
This firmware is designed for esp8266 modules which have most ESP I/O pins available and
|
|
at least 1MB flash. (The V1 firmware supports modules with 512KB flash).
|
|
The default connections are:
|
|
- URXD: connect to TX of microcontroller
|
|
- UTXD: connect to RX of microcontroller
|
|
- GPIO12: connect to RESET of microcontroller
|
|
- GPIO13: connect to ISP of LPC/ARM microcontroller (not used with Arduino/AVR)
|
|
- GPIO0: optionally connect green "conn" LED to 3.3V (indicates wifi status)
|
|
- GPIO2: optionally connect yellow "ser" LED to 3.3V (indicates serial activity)
|
|
|
|
If you are using an FTDI connector, GPIO12 goes to DTR and GPIO13 goes to CTS.
|
|
|
|
If you are using an esp-12 module, you can avoid the initial boot message from the esp8266
|
|
bootloader by using the swap-pins option. This swaps the esp8266 TX/RX to gpio15/gpio13 respectively.
|
|
|
|
The GPIO pin assignments can be changed dynamically in the web UI and are saved in flash.
|
|
|
|
Initial flashing
|
|
----------------
|
|
(This is not necessary if you receive one of the jn-esp or esp-bridge modules from the author!)
|
|
If you want to simply flash the provided firmware binary, you can download the latest
|
|
[release](https://github.com/jeelabs/esp-link/releases) and use your favorite
|
|
ESP8266 flashing tool to flash the bootloader, the firmware, and blank settings.
|
|
Detailed instructions are provided in the release notes.
|
|
|
|
Note that the firmware assumes a 512KB flash chip, which most of the esp-01 thru esp-11
|
|
modules appear to have. A larger flash chip should work but has not been tested.
|
|
|
|
Wifi configuration overview
|
|
------------------
|
|
For proper operation the end state the esp-link needs to arrive at is to have it
|
|
join your pre-existing wifi network as a pure station.
|
|
However, in order to get there the esp-link will start out as an access point and you'll have
|
|
to join its network to configure it. The short version is:
|
|
1. the esp-link creates a wifi access point with an SSID of the form `ESP_012ABC`
|
|
2. you join your laptop or phone to the esp-link's network as a station and you configure
|
|
the esp-link wifi with your network info by pointing your browser at http://192.168.4.1/
|
|
3. the esp-link starts to connect to your network while continuing to also be an access point
|
|
("AP+STA"), the esp-link may show up with a `esp-link.local` hostname
|
|
(depends on your DHCP/DNS config)
|
|
4. the esp-link succeeds in connecting and shuts down its own access point after 15 seconds,
|
|
you reconnect your laptop/phone to your normal network and access esp-link via its hostname
|
|
or IP address
|
|
|
|
LED indicators
|
|
--------------
|
|
Assuming appropriate hardware attached to GPIO pins, the green "conn" LED will show the wifi
|
|
status as follows:
|
|
- Very short flash once a second: not connected to a network and running as AP+STA, i.e.
|
|
trying to connect to the configured network
|
|
- Very short flash once every two seconds: not connected to a network and running as AP-only
|
|
- Even on/off at 1HZ: connected to the configured network but no IP address (waiting on DHCP)
|
|
- Steady on with very short off every 3 seconds: connected to the configured network with an
|
|
IP address (esp-link shuts down its AP after 15 seconds)
|
|
|
|
The yellow "ser" LED will blink briefly every time serial data is sent or received by the esp-link.
|
|
|
|
Wifi configuration details
|
|
--------------------------
|
|
After you have serially flashed the module it will create a wifi access point (AP) with an
|
|
SSID of the form `ESP_012ABC` where 012ABC is a piece of the module's MAC address.
|
|
Using a laptop, phone, or tablet connect to this SSID and then open a browser pointed at
|
|
http://192.168.4.1/, you should then see the esp-link web site.
|
|
|
|
Now configure the wifi. The desired configuration is for the esp-link to be a
|
|
station on your local wifi network so you can communicate with it from all your computers.
|
|
|
|
To make this happen, navigate to the wifi page and you should see the esp-link scan
|
|
for available networks. You should then see a list of detected networks on the web page and you
|
|
can select yours.
|
|
Enter a password if your network is secure (highly recommended...) and hit the connect button.
|
|
|
|
You should now see that the esp-link has connected to your network and it should show you
|
|
its IP address. _Write it down_. You will then have to switch your laptop, phone, or tablet
|
|
back to your network and then you can connect to the esp-link's IP address or, depending on your
|
|
network's DHCP/DNS config you may be able to go to http://esp-link.local
|
|
|
|
At this point the esp-link will have switched to STA mode and be just a station on your
|
|
wifi network. These settings are stored in flash and thereby remembered through resets and
|
|
power cycles. They are also remembered when you flash new firmware. Only flashing `blank.bin`
|
|
via the serial port as indicated above will reset the wifi settings.
|
|
|
|
There is a fail-safe, which is that after a reset or a configuration change, if the esp-link
|
|
cannot connect to your network it will revert back to AP+STA mode after 15 seconds and thus
|
|
both present its `ESP_012ABC`-style network and continue trying to reconnect to the requested network.
|
|
You can then connect to the esp-link's AP and reconfigure the station part.
|
|
|
|
One open issue (#28) is that esp-link cannot always display the IP address it is getting to the browser
|
|
used to configure the ssid/password info. The problem is that the initial STA+AP mode may use
|
|
channel 1 and you configure it to connect to an AP on channel 6. This requires the ESP8266's AP
|
|
to also switch to channel 6 disconnecting you in the meantime.
|
|
|
|
Troubleshooting
|
|
---------------
|
|
- verify that you have sufficient power, borderline power can cause the esp module to seemingly
|
|
function until it tries to transmit and the power rail collapses
|
|
- check the "conn" LED to see which mode esp-link is in (see LED info above)
|
|
- reset or power-cycle the esp-link to force it to become an access-point if it can't
|
|
connect to your network within 15-20 seconds
|
|
- if the LED says that esp-link is on your network but you can't get to it, make sure your
|
|
laptop is on the same network (and no longer on the esp's network)
|
|
- if you do not know the esp-link's IP address on your network, try `esp-link.local`, try to find
|
|
the lease in your DHCP server; if all fails, you may have to turn off your access point (or walk
|
|
far enough away) and reset/power-cycle esp-link, it will then fail to connect and start its
|
|
own AP after 15-20 seconds
|
|
|
|
Building the firmware
|
|
---------------------
|
|
The firmware has been built using the [esp-open-sdk](https://github.com/pfalcon/esp-open-sdk)
|
|
on a Linux system. Create an esp8266 directory, install the esp-open-sdk into a sub-directory.
|
|
Download the Espressif SDK (use the version mentioned in the release notes) from their
|
|
[download forum](http://bbs.espressif.com/viewforum.php?f=5) and also expand it into a
|
|
sub-directory. Then clone the esp-link repository into a third sub-directory.
|
|
This way the relative paths in the Makefile will work.
|
|
If you choose a different directory structure look at the Makefile for the appropriate environment
|
|
variables to define.
|
|
|
|
In order to OTA-update the esp8266 you should `export ESP_HOSTNAME=...` with the hostname or
|
|
IP address of your module.
|
|
|
|
Now, build the code: `make` in the top-level of esp-link.
|
|
|
|
A few notes from others (I can't fully verify these):
|
|
- You may need to install `zlib1g-dev` and `python-serial`
|
|
- Make sure you have the correct version of the esp_iot_sdk
|
|
- Make sure the paths at the beginning of the makefile are correct
|
|
- Make sure `esp-open-sdk/xtensa-lx106-elf/bin` is in the PATH set in the Makefile
|
|
|
|
Flashing the firmware
|
|
---------------------
|
|
This firmware supports over-the-air (OTA) flashing, so you do not have to deal with serial
|
|
flashing again after the initial one! The recommended way to flash is to use `make wiflash`
|
|
if you are also building the firmware.
|
|
If you are downloading firmware binaries use `./wiflash`.
|
|
`make wiflash` assumes that you set `ESP_HOSTNAME` to the hostname or IP address of your esp-link.
|
|
You can easily do that using something like `ESP_HOSTNAME=192.168.1.5 make wiflash`.
|
|
|
|
The flashing, restart, and re-associating with your wireless network takes about 15 seconds
|
|
and is fully automatic. The 512KB flash are divided into two 236KB partitions allowing for new
|
|
code to be uploaded into one partition while running from the other. This is the official
|
|
OTA upgrade method supported by the SDK, except that the firmware is POSTed to the module
|
|
using curl as opposed to having the module download it from a cloud server.
|
|
|
|
If you are downloading the binary versions of the firmware (links forthcoming) you need to have
|
|
both `user1.bin` and `user2.bin` handy and run `wiflash.sh <esp-hostname> user1.bin user2.bin`.
|
|
This will query the esp-link for which file it needs, upload the file, and then reconnect to
|
|
ensure all is well.
|
|
|
|
Note that when you flash the firmware the wifi settings are all preserved so the esp-link should
|
|
reconnect to your network within a few seconds and the whole flashing process should take 15-30
|
|
from beginning to end. If you need to clear the wifi settings you need to reflash the `blank.bin`
|
|
using the serial port.
|
|
|
|
The flash configuration and the OTA upgrade process is described in more detail in [FLASH.md](FLASH.md)
|
|
|
|
Serial bridge and connections to Arduino, AVR, ARM, LPC microcontrollers
|
|
------------------------------------------------------------------------
|
|
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`.
|
|
|
|
You can reprogram an Arduino / AVR microcontroller by pointing avrdude at port 23. Instead of
|
|
specifying a serial port of the form /dev/ttyUSB0 use `net:esp-link:23` with avrdude's -P option
|
|
(where `esp-link` is either the hostname of your esp-link or its IP address).
|
|
The 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.
|
|
|
|
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.
|
|
|
|
Note that multiple connections to port 23 can be made simultaneously. The 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!
|
|
|
|
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 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
|
|
- on: the UART log is always on
|
|
|
|
Note that even if the UART log is always off the bootloader prints to uart0 whenever the
|
|
esp8266 comes out of reset. This cannot be disabled.
|
|
|
|
Outbound TCP connections
|
|
------------------------
|
|
The attached micro-controller can open outbound TCP connections using a simple
|
|
[serial protocol](https://gist.github.com/tve/a46c44bf1f6b42bc572e).
|
|
More info and sample code forthcoming...
|
|
|
|
Outbound HTTP REST requests
|
|
---------------------------
|
|
The V2 versions of esp-link support the espduino SLIP protocol that supports simple outbound
|
|
HTTP REST requests. 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.
|
|
Support for MQTT is forthcoming.
|
|
|
|
You can find a demo sketch in a fork of the espduino library at
|
|
https://github.com/tve/espduino in the
|
|
[examples/demo folder](https://github.com/tve/espduino/tree/master/espduino/examples/demo).
|
|
|
|
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.
|
|
|