+ Add modules folder and add 18b20.lua module

modules/18b20.lua

@@ -0,0 +1,132 @@
+--------------------------------------------------------------------------------
+-- DS18B20 one wire module for NODEMCU
+-- NODEMCU TEAM
+-- LICENCE: http://opensource.org/licenses/MIT
+-- Vowstar <vowstar@nodemcu.com>
+--------------------------------------------------------------------------------
+
+-- Set module name as parameter of require
+local modname = ...
+local M = {}
+_G[modname] = M
+--------------------------------------------------------------------------------
+-- Local used variables
+--------------------------------------------------------------------------------
+-- DS18B20 dq pin
+local pin = nil
+-- DS18B20 default pin
+local defaultPin = 9
+--------------------------------------------------------------------------------
+-- Local used modules
+--------------------------------------------------------------------------------
+-- Table module
+local table = table
+-- String module
+local string = string
+-- One wire module
+local ow = ow
+-- Timer module
+local tmr = tmr
+-- Limited to local environment
+setfenv(1,M)
+--------------------------------------------------------------------------------
+-- Implementation
+--------------------------------------------------------------------------------
+C = 0
+F = 1
+K = 2
+function setup(dq) 
+    pin = dq
+	if(pin == nil) then
+		pin = defaultPin		
+	end
+	ow.setup(pin)
+end
+
+function addrs()
+	setup(pin)
+	tbl = {}
+	ow.reset_search(pin)
+	repeat
+		addr = ow.search(pin)
+		if(addr ~= nil) then
+			table.insert(tbl, addr)	
+		end
+		tmr.wdclr()
+	until (addr == nil)
+	ow.reset_search(pin)
+	return tbl
+end
+
+function readNumber(addr, unit)
+  result = nil
+  setup(pin)
+  flag = false
+  if(addr == nil) then
+    ow.reset_search(pin)
+	count = 0
+    repeat
+		count = count + 1
+		addr = ow.search(pin)
+		tmr.wdclr()
+	until((addr ~= nil) or (count > 100))
+	ow.reset_search(pin)
+  end	
+  if(addr == nil) then
+	return result
+  end
+  crc = ow.crc8(string.sub(addr,1,7))
+  if (crc == addr:byte(8)) then
+    if ((addr:byte(1) == 0x10) or (addr:byte(1) == 0x28)) then
+        -- print("Device is a DS18S20 family device.")
+        ow.reset(pin)
+        ow.select(pin, addr)
+        ow.write(pin, 0x44, 1)
+        -- tmr.delay(1000000)
+        present = ow.reset(pin)
+        ow.select(pin, addr)
+        ow.write(pin,0xBE,1)
+        -- print("P="..present)  
+        data = nil
+        data = string.char(ow.read(pin))
+        for i = 1, 8 do
+            data = data .. string.char(ow.read(pin))
+        end
+        -- print(data:byte(1,9))
+        crc = ow.crc8(string.sub(data,1,8))
+        -- print("CRC="..crc)
+        if (crc == data:byte(9)) then
+			if(unit == nil or unit == C) then
+				t = (data:byte(1) + data:byte(2) * 256) * 625
+			elseif(unit == F) then
+				t = (data:byte(1) + data:byte(2) * 256) * 1125 + 320000 
+			elseif(unit == K) then
+				t = (data:byte(1) + data:byte(2) * 256) * 625 + 2731500
+			end            
+            t1 = t / 10000
+            t2 = t % 10000
+            -- print("Temperature="..t1.."."..t2.." Centigrade")
+			-- result = t1.."."..t2
+			return t1, t2
+        end                   
+        tmr.wdclr()
+    else
+     -- print("Device family is not recognized.")
+    end
+  else
+   -- print("CRC is not valid!")
+  end
+  return result
+end
+
+function read(addr, unit)
+	t1, t2 = readNumber(addr, unit)
+	if((t1 == nil ) or (t2 ==nil)) then
+		return nil
+	else	
+		return t1.."."..t2
+	end
+end
+
+-- Return module table
+return M