94 lines
2.1 KiB
Lua
94 lines
2.1 KiB
Lua
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-- ******************************************************
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-- LM92 module for ESP8266 with nodeMCU
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--
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-- Written by Levente Tamas <levente.tamas@navicron.com>
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--
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-- GNU LGPL, see https://www.gnu.org/copyleft/lesser.html
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-- ******************************************************
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-- Module Bits
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local moduleName = ...
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local M = {}
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_G[moduleName] = M
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-- Default ID
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local id = 0
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-- Local vars
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local address = 0
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-- read regs for len number of bytes
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-- return table with data
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local function read_reg(reg_addr, len)
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local ret={}
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local c
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local x
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i2c.start(id)
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i2c.address(id, address ,i2c.TRANSMITTER)
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i2c.write(id,reg_addr)
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i2c.stop(id)
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i2c.start(id)
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i2c.address(id, address,i2c.RECEIVER)
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c=i2c.read(id,len)
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for x=1,len,1 do
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tc=string.byte(c,x)
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table.insert(ret,tc)
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end
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i2c.stop(id)
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return ret
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end
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--write reg with data table
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local function write_reg(reg_addr, data)
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i2c.start(id)
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i2c.address(id, address, i2c.TRANSMITTER)
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i2c.write(id, reg_addr)
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i2c.write(id, data)
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i2c.stop(id)
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end
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-- initialize i2c
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-- d: sda
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-- c: scl
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-- a: i2c addr 0x48|A1<<1|A0 (A0-A1: chip pins)
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function M.init(d,c,a)
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if (d ~= nil) and (c ~= nil) and (d >= 0) and (d <= 11) and (c >= 0) and ( c <= 11) and (d ~= l) and (a ~= nil) and (a >= 0x48) and (a <= 0x4b ) then
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sda = d
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scl = c
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address = a
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i2c.start(id)
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res = i2c.address(id, address, i2c.TRANSMITTER) --verify that the address is valid
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i2c.stop(id)
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if (res == false) then
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print("device not found")
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return nil
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end
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else
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print("i2c configuration failed") return nil
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end
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i2c.setup(id,sda,scl,i2c.SLOW)
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end
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-- Return the temperature data
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function M.getTemperature()
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local temperature
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local tmp=read_reg(0x00,2) --read 2 bytes from the temperature register
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temperature=bit.rshift(tmp[1]*256+tmp[2],3) --lower 3 bits are status bits
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if (temperature>=0x1000) then
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temperature= temperature-0x2000 --convert the two's complement
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end
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return temperature * 0.0625
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end
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-- Put the LM92 into shutdown mode
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function M.shutdown()
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write_reg(0x01,0x01)
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end
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-- Bring the LM92 out of shutdown mode
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function M.wakeup()
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write_reg(0x01,0x00)
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end
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return M
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