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diff --git a/rich.tex b/rich.tex
index 15d11431d4c31b9ada6e636fc6308314f9c5cccd..72b68cbfe45f4b7494f04e8aa0047612a3c1c54e 100755 (executable)
--- a/rich.tex
+++ b/rich.tex
@@ -427,3 +427,65 @@ for operating this unit.
                 and BIT\_HIGH settings}
        \label{fig:richadcsnoop}
 \end{figure}
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+\subsection{Trigger connection}
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+
+The RICH ADCMv3 needs at least one cable connection to CTS. Adding a second
+cable is not required, but recommended.
+
+\noindent A simple standard RJ45 ethernet cable is used as trigger distribution
+for the RICH. The selected pinout can be found in 
+table~\ref{richtriggerpinout}. The name given there for the signals corresponds
+to the small debug connector on the trigger distribution boards. Pins are 
+labeled there, the output levels are LVTTL standard. 
+
+\noindent \textbf{Note:} It is recommended to check the correct polarity of 
+signals by measuring the signal levels on the RICH trigger distribution 
+board. The timing trigger signal must be low ($0\>\mbox{V}$) if not active, 
+with a positive pulse of minimum $100\>\mbox{ns}$ length if a trigger is sent.
+
+\noindent \textbf{Hint:} If RICH does not send data, while readout is running
+perfectly, you can easily check for missing or broken timing trigger cables
+by reading the channel 0 (LVL1) error bits in one of the RICH hubs (details 
+can be found in section~\ref{hubstatusregs}).
+
+\noindent One trigger distribution board is used per sector, in addition one 
+distribution board does the fanout for all six sectors. This main distribution
+board is mounted on sector~0 top.
+
+\begin{table}
+\begin{center}
+\begin{tabularx}{\textwidth}{|c|X|X|X|X|}
+\hline
+\textbf{Pin} & \textbf{Name} & \textbf{Colour} & CTS pin & 
+\textbf{description}\\
+\hline
+\hline
+1 & IN2- & white/orange & ADO\_LV(61) & clock (-) \\
+2 & IN2+ & orange       & ADO\_LV(60) & clock (+) \\
+3 & IN3- & white/green  & ---         & reserved \\
+4 & IN1- & blue         & ADO\_LV(55) & timing trigger (-) \\
+5 & IN1+ & white/blue   & ADO\_LV(54) & timing trigger (+)  \\
+6 & IN3+ & green        & ---         & reserved \\
+7 & IN0- & white/brown  & ---         & reserved \\
+8 & IN0+ & brown        & ---         & reserved \\
+\hline
+\end{tabularx}
+\caption{RICH trigger pinout, colour codes according to T568B straight forward
+cable}
+\label{richtriggerpinout}
+\end{center}
+\end{table}
+
+\noindent For connection to CTS (version 1) at least two adaptor cables are 
+floating around, so you need to check which one you have.
+
+\noindent The necessary connections to the CTS adaptor cable are also marked 
+in table~\ref{richtriggerpinout}.
+
+\noindent For your orientation: usually the clock signal is on one end of the 
+68pin flat ribbon cable, while the timing trigger is on the fifth cable pair.
+
+