results.arch.tex

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