chap_1.tex

renesas M16C62 单片机调试通过的中断源码

锘縗section{Introduction}
The purpose of this small project is to get familiar with hardware interrupts on the Mulle platform and also the concepts of using 
semaphores. LED blinking is implemented as a reaction to an external interrupt. 

\section{Code description}
\begin{itemize}
    \item C Files - \texttt{main.c, hwinit.c, inithandler.c}
    \item Header Files - \texttt{hardware.h, inithandler.h, iodefine.h, sema.h}
	\item Others - \texttt{makefile, main.ls, start.S, vects.S}
\end{itemize}

\texttt{main.c} is the main file for this small project. It calls function \texttt{hw\_initialise} from \texttt{hwinit.c}, which 
sets port P81 as Output port. Port P81 is input port by default and connected with the battery.  Setting it as output port will 
turn off the battery measurements circuit. Semaphores are unset initially. Interrupt1 is enabled on level 3. The program then 
sets global interrupts on by executing \texttt{fset} command of assembly language. On every interrupt the interrupt handler sets 
the semaphore. The program checks the status of semaphore, if it is set then it unsets the semaphore and led status is checked 
by using a variable. If it is found on, it is set off and vice versa.   

To ease the compiling and linking, a \texttt{Makefile} is created. It generates \texttt{filename.mot} file for the M16C/62 microcontroller. 
This .mot file is the file that can load and run on MULLE. The Makefile uses a linker script, \texttt{main.ls}, to link the C files 
with the assembly files (\texttt{vects.S, start.S}) to generate a M16C/62 microcontroller \texttt{.mot} file. \\
\textbf {Note:} \small{A pre-compiled mot file \texttt{main.mot} is also included in the attached files. Anybody can download and 
run it on Mulle even if they dont have the compiler environment installed}

\section{How to run this program}
Open \texttt{m32c-elf Toolchain}\\
Type - \texttt{make}

It will produce three files, \texttt{main.map, main.mot}, and \texttt{main.out}. \texttt{.mot} file is Motorola Hex File for the M16C/62 
microcontroller. Download \texttt{main.mot} to MULLE and run it.

\section {Output on MULLE}
A LED placed on the Mulle will be ON at bootup. On an interrupt it will go off, and on next interrupt it will be on again. It will 
keep toggling on every interrupt.