% The Potato Processor - Processor Datasheet
% (c) Kristian Klomsten Skordal 2015 -2017 <kristian.skordal@wafflemail.net>
% Report bugs and issues on <https://github.com/skordal/potato/issues>

\documentclass[10pt,a4paper]{article}

\usepackage[pdftitle={The Potato Processor Datasheet},
	pdfauthor={Kristian Klomsten Skordal}]{hyperref}
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\begin{document}

\begin{minipage}{0.5\textwidth}
\raggedright\huge
\textsf{The Potato Project}
\end{minipage}
\begin{minipage}{0.5\textwidth}
\raggedleft\huge
\textsf{Processor Datasheet}
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\vspace{0.5em}
\noindent\rule{\linewidth}{1pt}\\

\begin{minipage}[t]{0.48\textwidth}

\section{Architecture}
\includegraphics[width=\textwidth]{diagram.png}

\section{Features}

\begin{itemize}
\item Supports the complete 32-bit RISC-V base integer ISA (RV32I) version 2.0
\item Supports machine mode from the RISC-V Privileged Architecture version 1.10
\item Includes a hardware timer with microsecond resolution and compare interrupt
\item Up to 8 IRQ inputs that can be individually enabled
\item Classic 5-stage RISC pipeline
\item Wishbone interface
\item Optional instruction cache
\item Automatic test suite
\end{itemize}

\section{Interface}

The processor includes a wishbone interface conforming to the B4 revision of the
wishbone specification.\\

\begin{tabularx}{\textwidth}{|l|X|}
\hline
Interface type & Master \\
Address port width & 32 bits \\
Data port width & 32 bits \\
Data port granularity & 8 bits \\
Maximum operand size & 32 bits \\
Endianess & Little \\
Sequence of data transfer & In-order \\
\hline
\end{tabularx}

\section{Specifications}

\center\includegraphics[width=0.7\textwidth]{riscv.png}
\url{http://riscv.org/specifications/}

\center\includegraphics[width=0.7\textwidth]{opencores.png}
\url{http://opencores.org/opencores,wishbone}

\end{minipage}\hfill
\begin{minipage}[t]{0.48\textwidth}

\section{Example Application}
\includegraphics[width=\textwidth]{example.png}

\section{Signals}

The processor is provided by a VHDL module named \texttt{pp\_potato}. All signals
are active high and the following signals are provided:\\

\begin{tabularx}{\textwidth}{|l|l|X|}
\hline
\textbf{Name} & \textbf{Width} & \textbf{Description} \\
\hline
\texttt{clk} & 1 & Processor clock \\
\texttt{timer\_clk} & 1 & 10~MHz timer clock \\
\texttt{reset} & 1 & Reset signal \\
\hline
\texttt{irq} & 8 & IRQ inputs \\
\hline
\texttt{wb\_adr\_out} & 32 & Wishbone address \\
\texttt{wb\_sel\_out} & 4 & Wishbone byte select \\
\texttt{wb\_cyc\_out} & 1 & Wishbone cycle \\
\texttt{wb\_stb\_out} & 1 & Wishbone strobe \\
\texttt{wb\_we\_out} & 1 & Wishbone write enable \\
\texttt{wb\_dat\_out} & 32 & Wishbone data output \\
\texttt{wb\_dat\_in} & 32 & Wishbone data input \\
\texttt{wb\_ack\_in} & 1 & Wishbone acknowledge \\
\hline
\end{tabularx}\\

An additional output, \texttt{test\_context\_out} is used to provide feedback to testbenches
when running automated tests. This port should be left unconnected.\\

\section{Tools and Utilities}

Tools for writing applications for the RISC-V architecture are available from the
RISC-V project, at:\\[1em]
\url{https://github.com/riscv/riscv-gnu-toolchain}\\

\end{minipage}

\vfill
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{\small
Project page: \url{https://github.com/skordal/potato}\\
Report bugs and issues on \url{https://github.com/skordal/potato/issues}}

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