my atmega.lua

--This module contains code which is used to communicate with Arduino.

-- Length of packets sent by Arduino on state requests
local OUTPUTS_COUNT = 8
local INPUTS_COUNT = 8
local ANALOGS_COUNT = 8
local RELAYS_COUNT = 6
local TIME_LENGTH = 2+2
local DATE_LENGTH = 4+2+2
local STATE_PACKET_SIZE =
    RELAYS_COUNT +
    INPUTS_COUNT +
    OUTPUTS_COUNT +
    ANALOGS_COUNT*4 +
    TIME_LENGTH +
    DATE_LENGTH +
    1 -- 'e'
local message = "test 2"


-- Utility functions.

local function setData(data)
    message = data:gsub("%ยง","")
end

---------------------------------------------------------------------------------------------------------------------


local atmega = {}

-- Send command, e.g. R1 or O2
function atmega.sendCommand(cmd)
    uart.write(0, "C" .. cmd)
end

function atmega.getMessage()
    return message
end


---------------------------------------------------------------------------------------------------------------------


-- Arduino sends only state packets via Serial.
--uart.on("data", "e", parseState, 0)
uart.on("data", "ยง", setData, 0)

-- Start polling
tmr.alarm(3, 1000, 1, function()
    atmega.sendCommand("ss")
end)


---------------------------------------------------------------------------------------------------------------------

return atmega