\subsection{MultiBoot controller}
\label{app:multiboot-regs}

Base address: 0x100
{
\rowcolors{2}{white}{gray!25}
\begin{longtable}{l l l p{.5\textwidth}}
\hline
\textbf{Offset} & \textbf{Reset} & \textbf{Name} 
		& \textbf{Description} \\
\hline
\endfirsthead
\hline
\hline
\endhead
\hline
\endfoot
0x0 &  0x00000000 & CR & Control Register\\
0x4 &  0x00000000 & SR & Status Register\\
0x8 &  0x00000000 & GBBAR & Golden Bitstream Base Address Register\\
0xc &  0x00000000 & MBBAR & MultiBoot Bitstream Base Address Register\\
0x10 & 0x10000000 & FAR & Flash Access Register\\
\end{longtable}
}

\vspace{11pt}
\subsubsection{CR -- Control Register}
\label{app:multiboot-regs-cr}


\vspace{11pt}
\noindent
\resizebox{\textwidth}{!}{
\begin{tabular}{>{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} }
31 & 30 & 29 & 28 & 27 & 26 & 25 & 24\\
\hline
\multicolumn{1}{|c}{-} & - & - & - & - & - & - & \multicolumn{1}{c|}{-}\\
\hline
23 & 22 & 21 & 20 & 19 & 18 & 17 & 16\\
\hline
\multicolumn{1}{|c}{-} & - & - & - & - & - & \multicolumn{1}{|c|}{\cellcolor{gray!25}IPROG} & \multicolumn{1}{|c|}{\cellcolor{gray!25}IPROG\_UNLOCK}\\
\hline
15 & 14 & 13 & 12 & 11 & 10 & 9 & 8\\
\hline
\multicolumn{1}{|c}{-} & - & - & - & - & - & - & \multicolumn{1}{c|}{-}\\
\hline
7 & 6 & 5 & 4 & 3 & 2 & 1 & 0\\
\hline
\multicolumn{1}{|c}{-} & \multicolumn{1}{|c|}{\cellcolor{gray!25}RDCFGREG} & \multicolumn{6}{|c|}{\cellcolor{gray!25}CFGREGADR[5:0]}\\
\hline
\end{tabular}
}

\begin{itemize}
\item \begin{small}
{\bf 
CFGREGADR
} [\emph{read/write}]: Configuration register address
\\
Address of FPGA configuration register to read.
\end{small}
\item \begin{small}
{\bf 
RDCFGREG
} [\emph{write-only}]: Read FPGA configuration register
\\
1 -- Start FPGA configuration register sequence. \\      0 -- No effect.
\end{small}
\item \begin{small}
{\bf 
IPROG\_UNLOCK
} [\emph{read/write}]: Unlock bit for the IPROG command
\\
1 -- Unlock IPROG bit. \\      0 -- No effect.
\end{small}
\item \begin{small}
{\bf 
IPROG
} [\emph{read/write}]: Start IPROG sequence
\\
1 -- Start IPROG configuration sequence \\      0 -- No effect \\      This bit needs to be unlocked by writing the IPROG\_UNLOCK bit first. \\      A write to this bit with IPROG\_UNLOCK cleared has no effect.
\end{small}
\item \begin{small}
\textbf{Unimplemented bits}: write as '0', read undefined
\end{small}
\end{itemize}
\vspace{11pt}
\subsubsection{SR -- Status Register}
\label{app:multiboot-regs-sr}

\vspace{11pt}
\noindent
\resizebox{\textwidth}{!}{
\begin{tabular}{>{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} }
31 & 30 & 29 & 28 & 27 & 26 & 25 & 24\\
\hline
\multicolumn{1}{|c}{-} & - & - & - & - & - & - & \multicolumn{1}{c|}{-}\\
\hline
23 & 22 & 21 & 20 & 19 & 18 & 17 & 16\\
\hline
\multicolumn{1}{|c}{-} & - & - & - & - & - & \multicolumn{1}{|c|}{\cellcolor{gray!25}WDTO} & \multicolumn{1}{|c|}{\cellcolor{gray!25}IMGVALID}\\
\hline
15 & 14 & 13 & 12 & 11 & 10 & 9 & 8\\
\hline
\multicolumn{8}{|c|}{\cellcolor{gray!25}CFGREGIMG[15:8]}\\
\hline
7 & 6 & 5 & 4 & 3 & 2 & 1 & 0\\
\hline
\multicolumn{8}{|c|}{\cellcolor{gray!25}CFGREGIMG[7:0]}\\
\hline
\end{tabular}
}

\begin{itemize}
\item \begin{small}
{\bf 
CFGREGIMG
} [\emph{read-only}]: Configuration register image
\\
Image of the FPGA configuration register at address CFGREGADR (see Configuration Registers section in Xilinx UG380~\cite{ug380}); validated by IMGVALID bit
\end{small}
\item \begin{small}
{\bf 
IMGVALID
} [\emph{read-only}]: Configuration register image valid
\\
1 -- CFGREGIMG valid \\      0 -- CFGREGIMG not valid;
\end{small}
\item \begin{small}
{\bf 
WDTO
} [\emph{read/write}]: MultiBoot FSM stalled at one point and was reset by FSM watchdog
\\
1 -- FSM watchdog fired \\      0 -- FSM watchdog has not fired
\end{small}
\item \begin{small}
\textbf{Unimplemented bits}: write as '0', read undefined
\end{small}
\end{itemize}
\vspace{11pt}
\subsubsection{GBBAR -- Golden Bitstream Base Address Register}
\label{app:multiboot-regs-gbbar}

\vspace{11pt}
\noindent
\resizebox{\textwidth}{!}{
\begin{tabular}{>{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} }
31 & 30 & 29 & 28 & 27 & 26 & 25 & 24\\
\hline
\multicolumn{8}{|c|}{\cellcolor{gray!25}BITS[31:24]}\\
\hline
23 & 22 & 21 & 20 & 19 & 18 & 17 & 16\\
\hline
\multicolumn{8}{|c|}{\cellcolor{gray!25}BITS[23:16]}\\
\hline
15 & 14 & 13 & 12 & 11 & 10 & 9 & 8\\
\hline
\multicolumn{8}{|c|}{\cellcolor{gray!25}BITS[15:8]}\\
\hline
7 & 6 & 5 & 4 & 3 & 2 & 1 & 0\\
\hline
\multicolumn{8}{|c|}{\cellcolor{gray!25}BITS[7:0]}\\
\hline
\end{tabular}
}

\begin{itemize}
\item \begin{small}
{\bf 
BITS
} [\emph{read/write}]: Bits of GBBAR register
\\
31..24 -- Read or fast-read OPCODE of the flash chip (obtain it from the flash chip datasheet) \\                     23..0  -- Golden bitstream address in flash
\end{small}
\item \begin{small}
\textbf{Unimplemented bits}: write as '0', read undefined
\end{small}
\end{itemize}
\vspace{11pt}
\subsubsection{MBBAR -- MultiBoot Bitstream Base Address Register}
\label{app:multiboot-regs-mbbar}

\vspace{11pt}
\noindent
\resizebox{\textwidth}{!}{
\begin{tabular}{>{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} }
31 & 30 & 29 & 28 & 27 & 26 & 25 & 24\\
\hline
\multicolumn{8}{|c|}{\cellcolor{gray!25}BITS[31:24]}\\
\hline
23 & 22 & 21 & 20 & 19 & 18 & 17 & 16\\
\hline
\multicolumn{8}{|c|}{\cellcolor{gray!25}BITS[23:16]}\\
\hline
15 & 14 & 13 & 12 & 11 & 10 & 9 & 8\\
\hline
\multicolumn{8}{|c|}{\cellcolor{gray!25}BITS[15:8]}\\
\hline
7 & 6 & 5 & 4 & 3 & 2 & 1 & 0\\
\hline
\multicolumn{8}{|c|}{\cellcolor{gray!25}BITS[7:0]}\\
\hline
\end{tabular}
}

\begin{itemize}
\item \begin{small}
{\bf 
BITS
} [\emph{read/write}]: Bits of MBBAR register
\\
31..24 -- Read or fast-read OPCODE of the flash chip (obtain it from the flash chip datasheet) \\                     23..0  -- MultiBoot bitstream start address in flash
\end{small}
\item \begin{small}
\textbf{Unimplemented bits}: write as '0', read undefined
\end{small}
\end{itemize}
\vspace{11pt}
\subsubsection{FAR -- Flash Access Register}
\label{app:multiboot-regs-far}

\vspace{11pt}
\noindent
\resizebox{\textwidth}{!}{
\begin{tabular}{>{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} >{\centering\arraybackslash}p{1.5cm} }
31 & 30 & 29 & 28 & 27 & 26 & 25 & 24\\
\hline
\multicolumn{1}{|c}{-} & - & - & \multicolumn{1}{|c|}{\cellcolor{gray!25}READY} & \multicolumn{1}{|c|}{\cellcolor{gray!25}CS} & \multicolumn{1}{|c|}{\cellcolor{gray!25}XFER} & \multicolumn{2}{|c|}{\cellcolor{gray!25}NBYTES[1:0]}\\
\hline
23 & 22 & 21 & 20 & 19 & 18 & 17 & 16\\
\hline
\multicolumn{8}{|c|}{\cellcolor{gray!25}DATA[23:16]}\\
\hline
15 & 14 & 13 & 12 & 11 & 10 & 9 & 8\\
\hline
\multicolumn{8}{|c|}{\cellcolor{gray!25}DATA[15:8]}\\
\hline
7 & 6 & 5 & 4 & 3 & 2 & 1 & 0\\
\hline
\multicolumn{8}{|c|}{\cellcolor{gray!25}DATA[7:0]}\\
\hline
\end{tabular}
}

\begin{itemize}
\item \begin{small}
{\bf 
DATA
} [\emph{read/write}]: Flash data field
\\
23..16 -- DATA[2]; after an SPI transfer, this register contains the value of data byte 2 read from the flash \\      15..8 -- DATA[1]; after an SPI transfer, this register contains the value of data byte 1 read from the flash \\      7..0  -- DATA[0]; after an SPI transfer, this register contains the value of data byte 0 read from the flash
\end{small}
\item \begin{small}
{\bf 
NBYTES
} [\emph{read/write}]: Number of DATA fields to send and receive in one transfer:
\\
 0x0 -- Send 1 byte (DATA[0]) \\      0x1 -- Send 2 bytes (DATA[0], DATA[1]) \\      0x2 -- Send 3 bytes (DATA[0], DATA[1], DATA[2])
\end{small}
\item \begin{small}
{\bf 
XFER
} [\emph{write-only}]: Start transfer to and from flash
\\
1 -- Start transfer \\      0 -- Idle
\end{small}
\item \begin{small}
{\bf 
CS
} [\emph{read/write}]: Chip select bit
\\
1 - Flash chip selected (CS pin low) \\      0 - Flash chip not selected (CS pin is high)
\end{small}
\item \begin{small}
{\bf 
READY
} [\emph{read-only}]: Flash access ready
\\
1 - Flash access completed \\      0 - Flash access in progress
\end{small}
\item \begin{small}
\textbf{Unimplemented bits}: write as '0', read undefined
\end{small}
\end{itemize}



