Simple CAN bus analyzer for RaceCapture using Lua scripting

RaceCapture_simple_Lua_CAN_bus_analyzer.lua

-- Simple CAN bus analyzer
-- This script is useful for reverse engineering CAN bus data
-- and detecting patterns.
--
-- Up to 100 individual 8 bit channels can be created. Additional channels will not be tracked.
-- CAN bus data will appear in the data stream with the channel name: <CAN ID>_<OFFSET>
-- Once script is running, you can monitor the data under Dashboard / Raw Channels View. 

----------------------------------------
--Configuration

--specify CAN bus; 0 if CAN1, 1 if CAN2
can_bus = 0

---------------------------------------
channel_count = 0

channels = {}
setTickRate(1000)

-- update the current channel value,
-- creating the channel as needed
function updateChannel(name, value)
  local cId = channels[name]
  if cId == nil then

  if channel_count >= 100 then 
     println('too many channels, could not add ' ..name)
     return
  end

    println('Adding new channel ' ..name)
    cId = addChannel(name, 10, 0, 0, 255)
    channel_count = channel_count + 1
    if cId ~= nil then
      -- stash the channel Id for next time
      channels[name] = cId
    else
      println('Could not add channel: ' ..name)
    end
  end
  setChannel(cId, value)
end

-- strips the trailing '.0' from formatted numbers
function fmtInt(val)
  return string.sub(val,1,-3)
end

-- loops through a CAN message, updating individual
-- channels for each byte
function updateCAN(id, data)
  for i=1, #data do
    updateChannel(fmtInt(id) ..'_' ..fmtInt((i-1)), data[i])
  end 
end

-- receive and process a CAN message
function processCAN()
  local id, ext, data = rxCAN(can_bus)
  if id ~= nil then updateCAN(id, data) end
end

function onTick() 
  processCAN()
end