\documentclass{article}
\usepackage{avremu}
\usepackage{listings}
\usepackage{hyperref}
\usepackage{filecontents}
\usepackage{tcolorbox}

\begin{filecontents*}{hello-world.c}
#include <avr/io.h>

int
main(void)
{
  char *str = "Hello World!";
  char *p = str;
  while (*p) {
    UDR = *p++;
  }
  asm  volatile ("break;");
}
\end{filecontents*}

\title{The \texttt{avremu} Package}
\author{Christian Dietrich\\
\url{stettberger@dokucode.de}}

\begin{document}

\maketitle

\begin{tcolorbox}
  \lstinputlisting[language=C]{hello-world.c}
  \tcblower
  \begin{lstlisting}[language=TeX]
\avrloadc{hello-world.c}
\avrrun
UDR='\avrUDR' in \avrinstrcount\ instructions
\end{lstlisting}
\end{tcolorbox}
\begin{tcolorbox}
\avrloadc{hello-world.c}\avrrun
UDR='\avrUDR' in \avrinstrcount\ instructions
\end{tcolorbox}

\end{document}

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