77 lines
2.1 KiB
Lua
77 lines
2.1 KiB
Lua
--'
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-- ds18b20 one wire example for NODEMCU (Integer firmware only)
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-- NODEMCU TEAM
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-- LICENCE: http://opensource.org/licenses/MIT
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-- Vowstar <vowstar@nodemcu.com>
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--'
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pin = 9
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ow.setup(pin)
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count = 0
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repeat
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count = count + 1
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addr = ow.reset_search(pin)
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addr = ow.search(pin)
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tmr.wdclr()
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until((addr ~= nil) or (count > 100))
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if (addr == nil) then
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print("No more addresses.")
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else
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print(addr:byte(1,8))
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crc = ow.crc8(string.sub(addr,1,7))
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if (crc == addr:byte(8)) then
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if ((addr:byte(1) == 0x10) or (addr:byte(1) == 0x28)) then
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print("Device is a DS18S20 family device.")
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repeat
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ow.reset(pin)
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ow.select(pin, addr)
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ow.write(pin, 0x44, 1)
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tmr.delay(1000000)
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present = ow.reset(pin)
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ow.select(pin, addr)
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ow.write(pin,0xBE,1)
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print("P="..present)
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data = nil
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data = string.char(ow.read(pin))
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for i = 1, 8 do
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data = data .. string.char(ow.read(pin))
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end
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print(data:byte(1,9))
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crc = ow.crc8(string.sub(data,1,8))
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print("CRC="..crc)
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if (crc == data:byte(9)) then
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t = (data:byte(1) + data:byte(2) * 256)
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-- handle negative temperatures
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if (t > 0x7fff) then
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t = t - 0x10000
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end
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if (addr:byte(1) == 0x28) then
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t = t * 625 -- DS18B20, 4 fractional bits
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else
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t = t * 5000 -- DS18S20, 1 fractional bit
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end
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local sign = ""
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if (t < 0) then
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sign = "-"
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t = -1 * t
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end
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-- Separate integral and decimal portions, for integer firmware only
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local t1 = string.format("%d", t / 10000)
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local t2 = string.format("%04u", t % 10000)
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local temp = sign .. t1 .. "." .. t2
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print("Temperature= " .. temp .. " Celsius")
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end
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tmr.wdclr()
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until false
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else
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print("Device family is not recognized.")
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end
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else
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print("CRC is not valid!")
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end
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end
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