51912d5505
With the IDF asserting full control over the linker scripts and insisting on
the application description being the first entry in the .flash.rodata
section, or previous method of doing link-time arrays stopped working.
Why? Because the build patched in a SHA256 digest straight into our arrays.
With the limited language of the gcc linker scripts I could find no other
way of getting it in cleanly.
The IDF "linker fragments" support can not be made to work for our needs:
- no support for setting alignment before including objects
- no support for declaring symbols
- no support for adding our terminating zeros
- insists on grouping objects by lib rather than by declared grouping,
which means we could at most have a single link-time-array using
the IDF mechanism
- also does not like underscores in section names, but that's just an
annoyance
So, the least bad option that I could come up with was to use a project-wide
makefile snippet to add a target in-between the IDF's generation of the
esp32.project.ld file, and the linking of our NodeMCU.elf. In this target
we read in the esp32.project.ld linker script, check whether we have our
arrays in there, and if not rewrites the linker script.
Oh, and the esp32.project.ld file only came into existence on the IDF 3.3
branch, so I had to change up the IDF to the latest release/3.3 as well.
I would've preferred a stable tag, but the v3.3-beta3 had a really nasty
regression for us (can't add partition entry), so that was a no-go.
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| .github | ||
| components | ||
| docs | ||
| examples | ||
| lua_compat | ||
| lua_examples | ||
| lua_modules | ||
| sdk | ||
| tools | ||
| .gitignore | ||
| .gitmodules | ||
| .travis.yml | ||
| CONTRIBUTING.md | ||
| LICENSE | ||
| Makefile | ||
| README.md | ||
| mkdocs.yml | ||
| sdkconfig.defaults | ||
README.md
NodeMCU on ESP32
A Lua based firmware for ESP32 WiFi SOC
NodeMCU is an eLua based firmware for the ESP32 WiFi SOC from Espressif. The firmware is based on the Espressif IoT Development Framework and uses a file system based on spiffs. The code repository consists of 98.1% C-code that glues the thin Lua veneer to the SDK.
The NodeMCU firmware is a companion project to the popular NodeMCU dev kits, ready-made open source development boards with ESP8266-12E chips.
Summary
- Easy to program wireless node and/or access point
- Based on Lua 5.1.4 (without debug, os modules)
- Asynchronous event-driven programming model
- 10+ built-in modules
- Firmware available with or without floating point support (integer-only uses less memory)
- Up-to-date documentation at https://nodemcu.readthedocs.io
Programming Model
The NodeMCU programming model is similar to that of Node.js, only in Lua. It is asynchronous and event-driven. Many functions, therefore, have parameters for callback functions. To give you an idea what a NodeMCU program looks like study the short snippets below. For more extensive examples have a look at the /lua_examples folder in the repository on GitHub.
-- a simple HTTP server
srv = net.createServer(net.TCP)
srv:listen(80, function(conn)
conn:on("receive", function(sck, payload)
print(payload)
sck:send("HTTP/1.0 200 OK\r\nContent-Type: text/html\r\n\r\n<h1> Hello, NodeMCU.</h1>")
end)
conn:on("sent", function(sck) sck:close() end)
end)
-- connect to WiFi access point
wifi.mode(wifi.STATION, true)
wifi.sta.on("connected", function() print("connected") end)
wifi.sta.on("got_ip", function(event, info) print("got ip "..info.ip) end)
-- mandatory to start wifi after reset
wifi.start()
wifi.sta.config({ssid="SSID", pwd="password", auto=true}, true)
Documentation
The entire NodeMCU documentation is maintained right in this repository at /docs. The fact that the API documentation is maintained in the same repository as the code that provides the API ensures consistency between the two. With every commit the documentation is rebuilt by Read the Docs and thus transformed from terse Markdown into a nicely browsable HTML site at https://nodemcu.readthedocs.io/en/dev-esp32/.
- How to build the firmware
- How to flash the firmware
- How to upload code and NodeMCU IDEs
- API documentation for every module
Support
See https://nodemcu.readthedocs.io/en/dev/en/support/.