node Module¶

Since	Origin / Contributor	Maintainer	Source
2014-12-22	Zeroday	Zeroday	node.c

The node module provides access to system-level features such as sleep, restart and various info and IDs.

node.bootreason()¶

Returns the boot reason and extended reset info.

The first value returned is the raw code, not the new "reset info" code which was introduced in recent SDKs. Values are:

• 1, power-on
• 2, reset (software?)
• 3, hardware reset via reset pin
• 4, WDT reset (watchdog timeout)

The second value returned is the extended reset cause. Values are:

• 0, power-on
• 1, hardware watchdog reset
• 2, exception reset
• 3, software watchdog reset
• 4, software restart
• 5, wake from deep sleep
• 6, external reset

In general, the extended reset cause supercedes the raw code. The raw code is kept for backwards compatibility only. For new applications it is highly recommended to use the extended reset cause instead.

In case of extended reset cause 3 (exception reset), additional values are returned containing the crash information. These are, in order, EXCCAUSE, EPC1, EPC2, EPC3, EXCVADDR, and DEPC.

Syntax¶

node.bootreason()

Parameters¶

none

Returns¶

rawcode, reason [, exccause, epc1, epc2, epc3, excvaddr, depc ]

Example¶

_, reset_reason = node.bootreason()
if reset_reason == 0 then print("Power UP!") end

node.chipid()¶

Returns the ESP chip ID.

Syntax¶

node.chipid()

Parameters¶

none

Returns¶

chip ID (number)

node.compile()¶

Compiles a Lua text file into Lua bytecode, and saves it as .lc file.

Syntax¶

node.compile("file.lua")

Parameters¶

filename name of Lua text file

Returns¶

nil

Example¶

file.open("hello.lua","w+")
file.writeline([[print("hello nodemcu")]])
file.writeline([[print(node.heap())]])
file.close()

node.compile("hello.lua")
dofile("hello.lua")
dofile("hello.lc")

node.dsleep()¶

Enters deep sleep mode, wakes up when timed out.

The maximum sleep time is 4294967295us, ~71 minutes. This is an SDK limitation. Firmware from before 05 Jan 2016 have a maximum sleeptime of ~35 minutes.

Syntax¶

node.dsleep(us, option)

Parameters¶

• us number (integer) or nil, sleep time in micro second. If us == 0, it will sleep forever. If us == nil, will not set sleep time.

• option number (integer) or nil. If nil, it will use last alive setting as default option.

  • 0, init data byte 108 is valuable
  • > 0, init data byte 108 is valueless
  • 0, RF_CAL or not after deep-sleep wake up, depends on init data byte 108
  • 1, RF_CAL after deep-sleep wake up, there will be large current
  • 2, no RF_CAL after deep-sleep wake up, there will only be small current
  • 4, disable RF after deep-sleep wake up, just like modem sleep, there will be the smallest current

Returns¶

nil

Example¶

--do nothing
node.dsleep()
--sleep μs
node.dsleep(1000000)
--set sleep option, then sleep μs
node.dsleep(1000000, 4)
--set sleep option only
node.dsleep(nil,4)

node.flashid()¶

Returns the flash chip ID.

Syntax¶

node.flashid()

Parameters¶

none

Returns¶

flash ID (number)

node.flashsize()¶

Returns the flash chip size in bytes. On 4MB modules like ESP-12 the return value is 4194304 = 4096KB.

Syntax¶

node.flashsize()

Parameters¶

none

Returns¶

flash size in bytes (integer)

node.heap()¶

Returns the current available heap size in bytes. Note that due to fragmentation, actual allocations of this size may not be possible.

Syntax¶

node.heap()

Parameters¶

none

Returns¶

system heap size left in bytes (number)

node.info()¶

Returns NodeMCU version, chipid, flashid, flash size, flash mode, flash speed.

Syntax¶

node.info()

Parameters¶

none

Returns¶

• majorVer (number)
• minorVer (number)
• devVer (number)
• chipid (number)
• flashid (number)
• flashsize (number)
• flashmode (number)
• flashspeed (number)

Example¶

majorVer, minorVer, devVer, chipid, flashid, flashsize, flashmode, flashspeed = node.info()
print("NodeMCU "..majorVer.."."..minorVer.."."..devVer)

node.input()¶

Submits a string to the Lua interpreter. Similar to pcall(loadstring(str)), but without the single-line limitation.

Syntax¶

node.input(str)

Parameters¶

str Lua chunk

Returns¶

nil

Example¶

sk:on("receive", function(conn, payload) node.input(payload) end)

See also¶

node.output()

node.output()¶

Redirects the Lua interpreter output to a callback function. Optionally also prints it to the serial console.

Syntax¶

node.output(function(str), serial_debug)

Parameters¶

• output_fn(str) a function accept every output as str, and can send the output to a socket (or maybe a file).
• serial_debug 1 output also show in serial. 0: no serial output.

Returns¶

nil

Example¶

function tonet(str)
  sk:send(str)
end
node.output(tonet, 1)  -- serial also get the lua output.

-- a simple telnet server
s=net.createServer(net.TCP)
s:listen(2323,function(c)
   con_std = c
   function s_output(str)
      if(con_std~=nil)
         then con_std:send(str)
      end
   end
   node.output(s_output, 0)   -- re-direct output to function s_ouput.
   c:on("receive",function(c,l)
      node.input(l)           -- works like pcall(loadstring(l)) but support multiple separate line
   end)
   c:on("disconnection",function(c)
      con_std = nil
      node.output(nil)        -- un-regist the redirect output function, output goes to serial
   end)
end)

See also¶

node.input()

node.readvdd33() --deprecated¶

Moved to adc.readvdd33().

node.restart()¶

Restarts the chip.

Syntax¶

node.restart()

Parameters¶

none

Returns¶

nil

node.restore()¶

Restores system configuration to defaults using the SDK function system_restore(), which doesn't document precisely what it erases/restores.

Syntax¶

node.restore()

Parameters¶

none

Returns¶

nil

Example¶

node.restore()
node.restart() -- ensure the restored settings take effect

node.setcpufreq()¶

Change the working CPU Frequency.

Syntax¶

node.setcpufreq(speed)

Parameters¶

speed constant 'node.CPU80MHZ' or 'node.CPU160MHZ'

Returns¶

target CPU frequency (number)

Example¶

node.setcpufreq(node.CPU80MHZ)

node.stripdebug()¶

Controls the amount of debug information kept during node.compile(), and allows removal of debug information from already compiled Lua code.

Only recommended for advanced users, the NodeMCU defaults are fine for almost all use cases.

Syntax¶

node.stripdebug([level[, function]])

Parameters¶

• level
  • 1, don't discard debug info
  • 2, discard Local and Upvalue debug info
  • 3, discard Local, Upvalue and line-number debug info
• function a compiled function to be stripped per setfenv except 0 is not permitted.

If no arguments are given then the current default setting is returned. If function is omitted, this is the default setting for future compiles. The function argument uses the same rules as for setfenv().

Returns¶

If invoked without arguments, returns the current level settings. Otherwise, nil is returned.

Example¶

node.stripdebug(3)
node.compile('bigstuff.lua')

See also¶

node.compile()

node.osprint()¶

Controls whether the debugging output from the Espressif SDK is printed. Note that this is only available if the firmware is build with DEVELOPMENT_TOOLS defined.

Syntax¶

node.osprint(enabled)

Parameters¶

• enabled This is either true to enable printing, or false to disable it. The default is false.

Returns¶

Nothing

Example¶

node.osprint(true)

node.egc module¶

node.egc.setmode()¶

Sets the Emergency Garbage Collector mode. The EGC whitepaper provides more detailed information on the EGC.

Syntax¶

node.egc.setmode(mode, [param])

Parameters¶

• mode
  • node.egc.NOT_ACTIVE EGC inactive, no collection cycle will be forced in low memory situations
  • node.egc.ON_ALLOC_FAILURE Try to allocate a new block of memory, and run the garbage collector if the allocation fails. If the allocation fails even after running the garbage collector, the allocator will return with error.
  • node.egc.ON_MEM_LIMIT Run the garbage collector when the memory used by the Lua script goes beyond an upper limit. If the upper limit can't be satisfied even after running the garbage collector, the allocator will return with error.
  • node.egc.ALWAYS Run the garbage collector before each memory allocation. If the allocation fails even after running the garbage collector, the allocator will return with error. This mode is very efficient with regards to memory savings, but it's also the slowest.
• level in the case of node.egc.ON_MEM_LIMIT, this specifies the memory limit.

Returns¶

nil

Example¶

node.egc.setmode(node.egc.ALWAYS, 4096) -- This is the default setting at startup. node.egc.setmode(node.egc.ON_ALLOC_FAILURE) -- This is the fastest activeEGC mode.

node.task module¶

node.task.post()¶

Enable a Lua callback or task to post another task request. Note that as per the example multiple tasks can be posted in any task, but the highest priority is always delivered first.

If the task queue is full then a queue full error is raised.

Syntax¶

node.task.post([task_priority], function)

Parameters¶

• task_priority (optional)
  • node.task.LOW_PRIORITY = 0
  • node.task.MEDIUM_PRIORITY = 1
  • node.task.HIGH_PRIORITY = 2
• function a callback function to be executed when the task is run.

If the priority is omitted then this defaults to node.task.MEDIUM_PRIORITY

Returns¶

nil

Example¶

for i = node.task.LOW_PRIORITY, node.task.HIGH_PRIORITY do 
  node.task.post(i,function(p2)
    print("priority is "..p2)
  end) 
end      

prints

priority is 2
priority is 1
priority is 0