174 lines
5.7 KiB
Lua
174 lines
5.7 KiB
Lua
--[[
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BME280 Lua module
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Requires i2c and bme280_math module
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Written by Lukas Voborsky, @voborsky
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]]
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local bme280 = {}
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-- bme280.setup()
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-- bme280:setup()
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-- bme280:read()
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-- bme280:altitude()
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-- bme280:dewpoint()
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-- bme280:qfe2qnh()
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-- bme280:startreadout()
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local type, assert = type, assert
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local table_concat, math_floor = table.concat, math.floor
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local i2c_start, i2c_stop, i2c_address, i2c_read, i2c_write, i2c_TRANSMITTER, i2c_RECEIVER =
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i2c.start, i2c.stop, i2c.address, i2c.read, i2c.write, i2c.TRANSMITTER, i2c.RECEIVER
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local bme280_math_setup, bme280_math_read, bme280_math_qfe2qnh, bme280_math_altitude, bme280_math_dewpoint =
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bme280_math.setup, bme280_math.read, bme280_math.qfe2qnh, bme280_math.altitude, bme280_math.dewpoint
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local tmr_create, tmr_ALARM_SINGLE = tmr.create, tmr.ALARM_SINGLE
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local BME280_I2C_ADDRESS1 = 0x76
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local BME280_I2C_ADDRESS2 = 0x77
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local BME280_REGISTER_CONTROL = 0xF4
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local BME280_REGISTER_CONTROL_HUM = 0xF2
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local BME280_REGISTER_CONFIG= 0xF5
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local BME280_REGISTER_CHIPID = 0xD0
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local BME280_REGISTER_DIG_T = 0x88 -- 0x88-0x8D ( 6)
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local BME280_REGISTER_DIG_P = 0x8E -- 0x8E-0x9F (18)
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local BME280_REGISTER_DIG_H1 = 0xA1 -- 0xA1 ( 1)
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local BME280_REGISTER_DIG_H2 = 0xE1 -- 0xE1-0xE7 ( 7)
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local BME280_REGISTER_PRESS = 0xF7 -- 0xF7-0xF9
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-- local BME280_FORCED_MODE = 0x01
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-- maximum measurement time in ms for maximum oversampling for all measures
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-- 113 > 1.25 + 2.3*16 + 2.3*16 + 0.575 + 2.3*16 + 0.575 ms
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local BME280_SAMPLING_DELAY =113
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-- Local functions
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local read_reg
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local write_reg
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local bme280_setup
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local bme280_read
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local bme280_startreadout
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-- -- Note that the space between debug and the arglist is there for a reason
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-- -- so that a simple global edit " debug(" -> "-- debug(" or v.v. to
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-- -- toggle debug compiled into the module.
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-- local print, node_heap = print, node.heap
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-- local function debug (fmt, ...) -- upval: cnt (, print, node_heap)
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-- if not bme280.debug then return end
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-- if (...) then fmt = fmt:format(...) end
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-- print("[bme280]", node_heap(), fmt)
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-- end
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--------------------------- Set up the bme280 object ----------------------------
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-- bme280 has method setup to create the sensor object and setup the sensor
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-- object created by bme280.setup() has methods: read, qfe2qnh, altitude, dewpoint
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---------------------------------------------------------------------------------
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function bme280.setup(id, addr, temp_oss, press_oss, humi_oss, power_mode, inactive_duration, IIR_filter, full_init)
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return bme280_setup(nil, id,
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addr, temp_oss, press_oss, humi_oss, power_mode, inactive_duration, IIR_filter, full_init)
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end
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------------------------------------------------------------------------------
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function bme280_setup(self, id, addr,
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temp_oss, press_oss, humi_oss, power_mode, inactive_duration, IIR_filter, full_init)
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addr = (addr==2) and BME280_I2C_ADDRESS2 or BME280_I2C_ADDRESS1
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full_init = full_init or true
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-- debug("%d %x %d", id, addr, BME280_REGISTER_CHIPID)
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local chipid = read_reg(id, addr, BME280_REGISTER_CHIPID, 1)
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if not chipid then
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return nil
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end
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-- debug("chip_id: %x", chipid:byte(1))
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local isbme = (chipid:byte(1) == 0x60)
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local buf = {}
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buf[1] = read_reg(id, addr, BME280_REGISTER_DIG_T, 6)
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buf[2] = read_reg(id, addr, BME280_REGISTER_DIG_P, 18)
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if (isbme) then
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buf[3] = read_reg(id, addr, BME280_REGISTER_DIG_H1, 1)
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buf[4] = read_reg(id, addr, BME280_REGISTER_DIG_H2, 7)
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end
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local sensor, config = bme280_math_setup(table_concat(buf),
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temp_oss, press_oss, humi_oss, power_mode, inactive_duration, IIR_filter)
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self = self or {
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setup = bme280_setup,
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read = bme280_read,
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startreadout = bme280_startreadout,
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qfe2qnh = bme280_math_qfe2qnh,
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altitude = bme280_math_altitude,
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dewpoint = bme280_math_dewpoint
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}
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self.id, self.addr = id, addr
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self._sensor, self._config, self._isbme = sensor, config, isbme
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if (full_init) then
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write_reg(id, addr, BME280_REGISTER_CONFIG, config[1])
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if (isbme) then write_reg(id, addr, BME280_REGISTER_CONTROL_HUM, config[2]) end
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write_reg(id, addr, BME280_REGISTER_CONTROL, config[3])
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end
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return self
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end
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function bme280_read(self, alt)
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local buf = read_reg(self.id, self.addr, BME280_REGISTER_PRESS, 8) -- registers are P[3], T[3], H[2]
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if buf then
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return bme280_math_read(self._sensor, buf, alt)
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else
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return nil
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end
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end
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function bme280_startreadout(self, callback, delay, alt)
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assert(type(callback) == "function", "invalid callback parameter")
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delay = delay or BME280_SAMPLING_DELAY
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if self._isbme then write_reg(self.id, self.addr, BME280_REGISTER_CONTROL_HUM, self._config[2]) end
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write_reg(self.id, self.addr, BME280_REGISTER_CONTROL, math_floor(self._config[3]:byte(1)/4)+ 1)
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-- math_floor(self._config[3]:byte(1)/4)+ 1
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-- an awful way to avoid bit operations but calculate (config[3] & 0xFC) | BME280_FORCED_MODE
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-- Lua 5.3 integer division // would be more suitable
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tmr_create():alarm(delay, tmr_ALARM_SINGLE,
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function()
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callback(bme280_read(self, alt))
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end
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)
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end
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function write_reg(id, dev_addr, reg_addr, data)
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i2c_start(id)
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if not i2c_address(id, dev_addr, i2c_TRANSMITTER) then
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-- debug("No ACK on address: %x", dev_addr)
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return nil
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end
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i2c_write(id, reg_addr)
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local c = i2c_write(id, data)
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i2c_stop(id)
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return c
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end
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function read_reg(id, dev_addr, reg_addr, n)
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i2c_start(id)
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if not i2c_address(id, dev_addr, i2c_TRANSMITTER) then
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-- debug("No ACK on address: %x", dev_addr)
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return nil
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end
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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, dev_addr, i2c_RECEIVER)
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local c = i2c_read(id, n)
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i2c_stop(id)
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return c
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end
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------------------------------------------------ -----------------------------
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return bme280
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