results.arch.tex

   1 \section{Architecture}
   2 \subsection{Devices}
   3 The client code for the devices is compiled from one codebase. For a device to
   4 be eligible for \glspl{mTask} it must be able to compile the shared codebase
   5 and implement (part of) the device specific interface. The shared codebase only
   6 uses standard \gls{C} and no special libraries or tricks are used. Therefore
   7 the code is compilable for almost any device or system. Note that it is not
   8 needed to implement a full interface. The full interface excluding the device
   9 specific settings is listed in Appendix~\ref{app:device-interface}. The
  10 interface works in a similar fashion as the \gls{EDSL}. Devices do not have to
  11 implement all functionality, this is analogous to the fact that views do not
  12 have to implement all type classes in the \gls{EDSL}.  When the device connects
  13 for the first time with a server the specifications of what is implemented is
  14 communicated.
  15
  16 At the time of writing the following device families are supported and can run
  17 the device software.
  18 \begin{itemize}
  19         \item \texttt{POSIX} compatible systems
  20
  21                 This includes systems running \emph{Linux} and \emph{MacOS}.
  22         \item \texttt{STM32} family microcontrollers supported by \texttt{ChibiOS}.
  23
  24                 This is tested in particular on the \texttt{STM32f7x} series \gls{ARM}
  25                 development board.
  26         \item Microcontrollers programmable by the \emph{Arduino} \gls{IDE}.\\
  27
  28                 This does not only include \emph{Arduino} compatible boards but also
  29                 other boards capable of running \emph{Arduino} code. The code
  30                 has been found working on the \texttt{ESP8266} powered \emph{NodeMCU}.
  31                 It is tested on devices as small as the regular \emph{Arduino UNO}
  32                 board that only boasts a meager \emph{2K} of \emph{RAM}.
  33 \end{itemize}
  34
  35 \subsection{Specification}
  36 Devices are stored in a record type and all devices in the system are stored in
  37 a \gls{SDS} containing all devices. From the macro settings in the interface
  38 file a profile is created for the device that describes the specification. When
  39 a connection between the server and a client is established the server will
  40 send a request for specification. The client will serialize his specification
  41 and send it to the server so that the server knows what the client is capable
  42 of. The exact specification is listed in Listing~\ref{lst:devicespec}
  43
  44 \begin{lstlisting}[language=Clean,label={lst:devicespec},
  45         caption={Device specification for \glspl{mTask}}]
  46 :: MTaskDeviceSpec =
  47         {haveLed     :: Bool
  48         ,haveAio     :: Bool
  49         ,haveDio     :: Bool
  50         ,bytesMemory :: Int
  51         }
  52 \end{lstlisting}
  53
  54 \subsection{Communication}
  55 The communication to and fro a device runs via a single \gls{SDS}. Every
  56 device has a specific resource that is used to connect to the device. The
  57 current system supports connecting devices via a serial connection and via a
  58 \gls{TCP} connection. Every device has the type \CI{MTaskDevice} and which
  59 is listed in Listing~\ref{lst:mtaskdevice}. When a device is added a background
  60 task is started that runs the \CI{synFun}. The \CI{synFun} is the task that
  61 synchronizes the channel \gls{SDS} with the actual device. For the \gls{TCP}
  62 device this is a simple \CI{tcpconnect}. The \CI{TaskId} of the background task
  63 is saved to be able to stop the task in the future. When the task is unable to
  64 connect it will set the \CI{deviceError} field to notify the user.
  65 \todo{netter maken}
  66
  67 \begin{lstlisting}[language=Clean,caption={Device type},label={lst:mtaskdevice}]
  68 :: Channels :== ([MTaskMSGRecv], [MTaskMSGSend], Bool)
  69 :: MTaskResource
  70         = TCPDevice TCPSettings
  71         | SerialDevice TTYSettings
  72 :: MTaskDevice =
  73                 { deviceTask :: Maybe TaskId
  74                 , deviceError :: Maybe String
  75                 , deviceChannels :: String
  76                 , deviceName :: String
  77                 , deviceTasks :: [MTaskTask]
  78                 , deviceData :: MTaskResource
  79                 , deviceSpec :: Maybe MTaskDeviceSpec
  80         }
  81
  82 class MTaskDuplex a where
  83         synFun :: a (Shared Channels) -> Task ()
  84 \end{lstlisting}