-%\subsection{Serial port communication in Clean and iTasks}
-%In the first exploration stage I added duplex serial port communication to
-%iTasks in the same way as TCP is added. To make it work several changes had to
-%be done to the iTasks core to allow backgroundtasks to be added at runtime. The
-%function shown in Listing~\ref{lst:serialtask} results into a task that
-%sends the data added to the output queue through the serial port and adds data
-%received to the input queue for the user to process.
-%
-%\begin{lstlisting}[caption={Serial port communication in iTasks},
-% language=Clean,label={lst:serialtask}]
-%syncSerialChannel :: String TTYSettings (Shared ([String],[String],Bool)) -> Task ()
-%
-%:: ByteSize = BytesizeFive | BytesizeSix | BytesizeSeven | BytesizeEight
-%:: Parity = ParityNone | ...ParityOdd | ParityEven | ParitySpace | ParityMark
-%:: BaudRate = ... | B9600 | B19200 | ...
-%:: TTYSettings = {
-% baudrate :: BaudRate,
-% bytesize :: ByteSize,
-% parity :: Parity,
-% stop2bits :: Bool,
-% xonxoff :: Bool}
-%\end{lstlisting}
-%
-%\subsection{mTasks}
-%The core of the project revolves around the embedded domain specific language
-%(EDSL) called mTask designed by Pieter Koopman. mTasks is used to use the task
-%oriented programming on microcontrollers in a type-safe environment. Originally
-%mTasks are compiled to c code that could be compiled for arduino compatible
-%devices. Such generated code will be flashed to the program memory once. In
-%short, the original mTask system is comparable to an entire iTasks sytem
-%including the engine.
-%
-%For this project the imperative language constructs of the mTask DSL are used.
-%Listing~\ref{lst:mtask} shows some of these class base DSL components for
-%things like arithmetics, sequencing, conditionals, shared data sources and
-%interaction with the user LEDs. Together with some helper functions code
-%programmed in this DSL can be compiled to bytecode and sent to a device.
-%
-%\begin{lstlisting}[language=Clean,label={lst:mtask},
-% caption={Parts of the mTask DSL}]
-%:: Upd = Upd
-%:: Expr = Expr
-%:: Stmt = Stmt
-%:: UserLED = LED1 | LED2 | LED3
-%
-%:: Main a = {main :: a}
-%
-%class arith v where
-% lit :: t -> v t Expr | ...
-% (+.) infixl 6 :: (v t p) (v t q) -> v t Expr | ...
-%class IF v where
-% IF :: (v Bool p) (v t q) (v s r) -> v () Stmt | isExpr p
-%class sds v where
-% sds :: ((v t Upd)->In t (Main (v c s))) -> (Main (v c s)) | ...
-% pub :: (v t Upd) -> v t Expr | ...
-%class seq v where
-% (:.) infixr 0 :: (v t p) (v u q) -> v u Stmt | ...
-%class assign v where
-% (=.) infixr 2 :: (v t Upd) (v t p) -> v t Expr | ...
-%class noOp v where noOp :: v t p
-%class userLed v where
-% ledOn :: UserLED -> (v () Stmt)
-% ledOff :: UserLED -> (v () Stmt)
-%\end{lstlisting}
-%
-%\subsection{iTasks}
-%In iTasks several tasks have been devised to handle the communication. Moreover
-%the tasks will synchronize the shared data sources in the mTask domain with
-%real SDSs in the iTasks domain allowing for communication between mTasks and
-%iTasks tasks. To not clutter the communication channels the SDSs are not
-%synchronized on every change on the device. When a share changes on the server
-%his new value will be pushed to the device immediately. When a share is updated
-%on the client it must be explicitly published using. This approach has been
-%taken because some shares might be only used internally and therefore would
-%clutter the communication channels that could be low-bandwidth.
-%
-%
-%\subsection{Devices}
-%For the devices an engine has been built that can receive mTasks and SDSs and
-%execute them accordingly. To add a new device to the list the programmer just
-%has to implement a relatively small interface. All the other functionality is
-%using standard C or the interface. This interface is listed in~%
-%\ref{lst:interface} and includes reading and writing data, controlling the
-%peripherals and some auxiliary functions.
-%
-%\begin{lstlisting}[language=c,caption={Device interface},label={lst:interface}]
-%uint8_t read_byte(void);
-%void write_byte(uint8_t b);
-%
-%void write_dpin(uint8_t i, bool b);
-%bool read_dpin(uint8_t i);
-%
-%void write_apin(uint8_t i, uint8_t a);
-%uint8_t read_apin(uint8_t i);
-%
-%long millis(void);
-%bool input_available(void);
-%void delay(long ms);
-%
-%void setup(void);
-%void debug(char *fmt, ...);
-%void pdie(char *s);
-%void die(char *fmt, ...);
-%\end{lstlisting}
-%
-%mTasks run either at a fixed interval or are one-shot which is added to the
-%message. The entire protocol specification can be found in the code that is
-%available. When an mTask is one-shot it will only be executed once and then
-%removed. This can be useful for user related tasks such as shutting down blinds
-%or turning on lights for an indefinite time. mTasks that run at a fixed
-%interval time can be used to monitor sensors or to periodically communicate
-%with peripherals like LCD screens.
-%
-%There are many things to be improved upon in future research. Most likely these
-%points will be touched upon in my Master's thesis research.
-%\begin{itemize}
-% \item Support task combinators and functions.
-%
-% The mTask language already supports the step combinator and it might be
-% fruitful to add for more expressively. Moreover functions would also
-% add a lot. They can be used to share code between tasks to reduce the
-% bytecode size.
-% \item Seamless integration with iTasks.
-%
-% At the moment everything works but is hacked together. I would like to
-% extend this with a more robust system that allows adding devices on the
-% fly and adds functionality to monitor the mTask devices.
-% \item Dynamic mTask/SDS allocation.
-%
-% Currently all client data for mTask and SDS storage is statically
-% allocated. This means that when only a few tasks are used the memory
-% needed is too high. This can be improved upon by only allocating
-% resources for tasks when they are requested and this would allow the
-% system to run on low memory devices like arduino's.
-% \item Extend on SDSs.
-%
-% In the current system the shared data sources used in mTask programs
-% live in a different domain and are synchronized with an iTask
-% counterpart. Programming mTasks could be made more intuitive if you
-% could use standard SDSs from iTasks. Moreover, at the moment only
-% integer and boolean shares are allowed. This really should be extended
-% to at least strings.
-% \item Slicing tasks.
-%
-% Every mTask runs in its entirety and to not run into race and
-% scheduling problems loops are not allowed in the mTasks. An improvement
-% to this could be multithreading the tasks by giving them slices of
-% computation and pausing them every slice. In this way loops could be
-% allowed without blocking the entire system. It does require more memory
-% however.
-% \item Run tasks when an interrupt fires.
-%
-% Tasks can be scheduled either one-shot or at an interval. It might be
-% useful to tie mTasks to hardware interrupts to increase responsiveness
-% and possibly battery life. These interrupts do not need to be hardware
-% based. A usecase might be to run a task when some other task is
-% yielding a value (see task combinators) or to run a task when a shared
-% data source is received from the server.
-%\end{itemize}
repositories / msc-thesis1617.git / blobdiff