diff options
Diffstat (limited to 'ccs811.lua')
| -rw-r--r-- | ccs811.lua | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/ccs811.lua b/ccs811.lua new file mode 100644 index 0000000..8753303 --- /dev/null +++ b/ccs811.lua @@ -0,0 +1,66 @@ +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 |