Commit f5e47546 authored by Christian Fibich's avatar Christian Fibich Committed by Stefan Tauner
Browse files

Added documentation for t_fiu_records and fault model bits

parent 935e0b74
......@@ -80,9 +80,28 @@ selection. If, however, area or timing is critical, fault injection units
can be configured to implement only one fault model each.
Fault injection units are daisy-chained in \texttt{\texttt{fault\_injection\_top}} as described in \Cref{sec:hw_fi_top}.
\fixme{Add this as footnote to the specification of \texttt{t\_fiu\_records}?
Due to the encoding of the forwarding/fault type in 3 bits, another 2 fault types can be added easily.
More than the total of 8 forwarding types would require some hardware and software changes.}
The number of \acp{FIU} and their configuration are determined by the constant
\texttt{c\_fiu\_config} in the VHDL package \texttt{public\_config\_pkg}.
This constant is of the type \texttt{t\_fiu\_records}, which is an array
of \texttt{t\_single\_fiu\_record}s. This record consists of the following
\item \texttt{fault\_mode}: specifies which fault model is available at runtime.
This is an instance of the type \texttt{t\_select\_fault\_models}
from \texttt{fault\_selection\_type\_pkg}.
\item \texttt{lfsr\_mask}: specifies an AND mask for the global \ac{LFSR}.
The result of the AND operation is in turn
AND-reduced to a single bit which is used
in the stuck-open fault model.
The fault model of \acp{FIU} configured as \texttt{RUNTIME} is configured
at runtime using a 3-bit-wide configuration register for each fault configuration
as seen in Figure~\ref{fig:hardwareblockd}. Six of the possible values
are already mapped to fault models as can be seen in the VHDL package
\texttt{fault\_injection\_unit\_pkg} (via the constants \texttt{c\_fault\_select\_*}).
Two more fault models can be added without changing the width of these
\caption{Design Constants}
......@@ -101,4 +120,4 @@ More than the total of 8 forwarding types would require some hardware and softwa
\caption{Toplevel VHDL Outputs}
\ No newline at end of file
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