An optional ``shutter'' can be enabled. When the shutter is ``closed'' triggers are vetoed and no triggers are sent. When the shutter is ``open'' triggers can be generated and sent to active DUTs.\\
The shutter cycle can either be started by an external signal or synchronized by a counter clocked by the system clock.\\
The external signal, if used, must be connected to one of the trigger inputs (i.e. of the the six the LEMO inputs).\\
An optional ``shutter'' can be enabled to synchronize the acquisition window to a signal, such as the spill signal from a beam line.\\
When the shutter is ``closed'' triggers are vetoed and no triggers are sent. When the shutter is ``open'' triggers can be generated and sent to active \gls{dut}s.\\
The shutter cycle can either be started by an external signal or synchronized by a counter clocked by the system clock (i.e. internally-generated shutter, which can be used to debug hardware).\\
The external signal, if used, must be connected to one of the six LEMO trigger inputs.\\
\begin{alertinfo}{If the external signal is used, an appropriate threshold should be set to the corresponding input. The input used for synchronizing the shutter should not be used in the trigger mask.}
\end{alertinfo}
Figure~\ref{fig:shutter_timing} illustrates the timing of the shutter.\\
Behaviour of the shutter is controlled by the IPBus registers that can be configured using the configuration parameters described in table~\ref{tab:shutter_registers}. The parameters should be included in the config file described in section~\ref{ch:configFile}.
Figure~\ref{fig:shutter_timing} illustrates the timing of the shutter sequence.\\
When the shutter is open, the \gls{tlu} will assert the \verb|CONT| line (see table~\ref{tab:HDMIpins}), indicating to the \gls{dut} that the sequence is active.\\
Behaviour of the shutter is controlled by the IPBus registers described in table~\ref{tab:shutter_registers}. If using EUDAQ, the registers can be written by including the corresponding steering parameters.
The parameters should be included in the config file described in section~\ref{ch:configFile}.
\caption{Shutter Timing: the E$_{min}$ signal is fed to one of the trigger inputs and initiates the shutter sequence: after a programmable delay t$_{1}$ the \gls{tlu} asserts the \emph{shutter} signal. The unit will start to issue trigger signals to the \gls{dut} once a programmable time t$_{2}$ has elapsed. The window between t$_{1}$ and t$_{2}$ can be used to ensure the \gls{dut} is configured and ready to accept triggers. The unit will issue triggers until the end of the shutter window, determined by t$_{3}$.}
\label{fig:shutter_timing}
\end{figure}
%\begin{table}
...
...
@@ -28,19 +31,19 @@ Behaviour of the shutter is controlled by the IPBus registers that can be config
EnableShutterMode &\begin{tabular}[c]{@{}l@{}}If 1, shutter mode is enabled.\\ If 0, shutter mode is disabled.\end{tabular}&& ControlRW \\\hline
ShutterSource & Selects which input is used to trigger shutter sequence. & Range 0:5 & ShutterSelectRW \\\hline
InternalShutterInterval &\begin{tabular}[c]{@{}l@{}}Internal shutter period when using internal sequence.\\ Set to 0 to not use internal shutter generator.\end{tabular}&\begin{tabular}[c]{@{}l@{}}32-bit vale.\\ Units of 25 ns clock cycles.\end{tabular}& InternalShutterPeriodRW \\\hline
ShutterOnTime & Time between start of sequence and shutter asserted (t$_{1}$). &\begin{tabular}[c]{@{}l@{}}32-bit vale.\\ Units of 25 ns clock cycles.\end{tabular}& ShutterOnTimeRW \\\hline
ShutterVetoOffTime & Time between start of sequence and veto being de-asserted (t$_{2}$). &\begin{tabular}[c]{@{}l@{}}32-bit vale.\\ Units of 25 ns clock cycles.\end{tabular}& ShutterVetoOffTimeRW \\\hline
ShutterOffTime &\begin{tabular}[c]{@{}l@{}}Time between start of sequence and time at which\\ shutter de-asserted and veto reasserted (t$_{3}$).\end{tabular}&\begin{tabular}[c]{@{}l@{}}32-bit vale.\\ Units of 25 ns clock cycles.\end{tabular}& ShutterOffTimeRW \\\hline
\end{tabular}
\caption{Configuration parameters and corresponding IPBus registers controlling behaviour of shutter.}
EnableShutterMode &\begin{tabular}[c]{@{}l@{}}If 1, shutter mode is enabled.\\ If 0, shutter mode is disabled.\end{tabular}&& ControlRW \\\hline
ShutterSource & Selects which input is used to trigger shutter sequence. & Range 0:5 & ShutterSelectRW \\\hline
InternalShutterInterval &\begin{tabular}[c]{@{}l@{}}Internal shutter period when using internal sequence.\\ Set to 0 to not use internal shutter generator.\end{tabular}&\begin{tabular}[c]{@{}l@{}}32-bit vale.\\ Units of 25 ns clock cycles.\end{tabular}& InternalShutterPeriodRW \\\hline
ShutterOnTime & Time between start of sequence and shutter asserted (t$_{1}$). &\begin{tabular}[c]{@{}l@{}}32-bit vale.\\ Units of 25 ns clock cycles.\end{tabular}& ShutterOnTimeRW \\\hline
ShutterVetoOffTime & Time between start of sequence and veto being de-asserted (t$_{2}$). &\begin{tabular}[c]{@{}l@{}}32-bit vale.\\ Units of 25 ns clock cycles.\end{tabular}& ShutterVetoOffTimeRW \\\hline
ShutterOffTime &\begin{tabular}[c]{@{}l@{}}Time between start of sequence and time at which\\ shutter de-asserted and veto reasserted (t$_{3}$).\end{tabular}&\begin{tabular}[c]{@{}l@{}}32-bit vale.\\ Units of 25 ns clock cycles.\end{tabular}& ShutterOffTimeRW \\\hline
\end{tabular}
\caption{Configuration parameters and corresponding IPBus registers controlling behaviour of shutter.}