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local ccs811 = {}
local device_address = 0x5a
ccs811.mode = nil
function ccs811.start()
local ret = true
i2c.start(0)
if not i2c.address(0, device_address, i2c.TRANSMITTER) then
ret = false
end
i2c.write(0, 0xf4)
i2c.stop(0)
return ret
end
function ccs811.setMode(mode)
local ret = true
i2c.start(0)
if not i2c.address(0, device_address, i2c.TRANSMITTER) then
ret = false
end
i2c.write(0, 0x01, bit.lshift(mode, 4))
i2c.stop(0)
ccs811.mode = mode
return ret
end
function ccs811.setEnv(humi, temp)
local ret = true
i2c.start(0)
if not i2c.address(0, device_address, i2c.TRANSMITTER) then
ret = false
end
i2c.write(0, 0x05, math.floor(humi) * 2, 0, (math.floor(temp) + 25) * 2, 0)
i2c.stop(0)
return ret
end
function ccs811.read()
local ret = true
if ccs811.mode == nil then
ccs811.setMode(1)
return
end
i2c.start(0)
if not i2c.address(0, device_address, i2c.TRANSMITTER) then
ret = false
end
i2c.write(0, 0x02)
i2c.start(0)
if not i2c.address(0, device_address, i2c.RECEIVER) then
ret = false
end
local data = i2c.read(0, 6)
i2c.stop(0)
ccs811.eco2 = bit.lshift(string.byte(data, 1), 8) + string.byte(data, 2)
ccs811.tvoc = bit.lshift(string.byte(data, 3), 8) + string.byte(data, 4)
ccs811.status = string.byte(data, 5)
ccs811.err_id = string.byte(data, 6)
return ret
end
return ccs811
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