From bfcc051aad13328f73946e9787f5a689daa15028 Mon Sep 17 00:00:00 2001
From: hadaq <hadaq>
Date: Mon, 24 Sep 2012 12:43:29 +0000
Subject: [PATCH] EPOCH counter information is added - cu

---
 trb3/TdcDataFormat.tex  | 36 ++++++++++++++++++++++++++++++++++--
 trb3/TdcSlowControl.tex |  4 +++-
 2 files changed, 37 insertions(+), 3 deletions(-)

diff --git a/trb3/TdcDataFormat.tex b/trb3/TdcDataFormat.tex
index f5b9382..546efea 100644
--- a/trb3/TdcDataFormat.tex
+++ b/trb3/TdcDataFormat.tex
@@ -124,7 +124,8 @@ The debug information sent is given in Table \ref{tab:tdcDebugWords}.
       \multirow{2}{*}{"01000"}	& \multirow{2}{*}{Spike number}			& Number of spikes (pulses narrower than 40~ns) detected at the timing trigger input\\\hline
       \multirow{3}{*}{"01001"}	& \multirow{3}{*}{Idle time}			& Total time length, that the readout FSM waited in the idle state (with granularity of 10~ns)\\\hline
       \multirow{3}{*}{"01010"}	& \multirow{3}{*}{Wait time}			& Total time length, that the readout FSM waited in the wait states (with granularity of 10~ns)\\\hline
-      \multirow{2}{*}{"01011"}	& \multirow{2}{*}{Total empty channels}		& Number of empty channels since the last reset signal\\
+      \multirow{2}{*}{"01011"}	& \multirow{2}{*}{Total empty channels}         & Number of empty channels since the last reset signal\\\hline
+      \multirow{2}{*}{"01100"}	& \multirow{2}{*}{Readout time} 		& Total time length, that the readout occured (with granularity of 10~ns)\\
       \hline
     \end{tabularx}
   \caption{Debug information word bitmap.}
@@ -135,6 +136,37 @@ The debug information sent is given in Table \ref{tab:tdcDebugWords}.
 The debug words sent with DAQ can be accessed also via slow control registers (see Table \ref{tab:tdcStatusReg1} and Table \ref{tab:tdcStatusReg2}).
 
 \newpage
+
+\subsubsection{EPOCH Counter}
+
+As the global coarse counter has the time limit of \~10~us, a overflow counter
+(EPOCH counter) is implemented in order to increase the measurement range. The
+data format of the \textbf{\textit{EPOCH Counter}} word is shown below:
+
+\begin{table}[h]
+  \centering
+    \begin{tabular}{|W{1.275cm}|W{7.225cm}|W{5.1cm}|}
+      \hline
+      3 bits	& 17 bits       & 12 bits\\
+      "011"	& reserved      & EPOCH Counter\\
+      \hline
+    \end{tabular}
+  \caption{The data format of the \textit{EPOCH Counter} word.}
+  \label{tab:tdcReservedWord}
+\end{table}
+
+The EPOCH counter is first designed with 12 bits increasing the total
+measurement range up to \texttildelow41,9~ms. For each channel an individual EPOCH
+counter is implemented and they are incremented, when the coarse counter
+wraps around. The value of the EPOCH counter is kept in a register before it
+is written in the channel memory. It is only written in the memory, if a time
+measurement takes place after the last increment of the EPOCH counter. The
+EPOCH counter word is written in the memory only once per channel for each
+increment, thus saving bandwidth. In order to be on the safe side and not
+overflow the EPOCH counter, the readout trigger frequency can be set minimum
+to 24~Hz.
+
+
 \subsubsection{RESERVED}
 
 The data format of the \textbf{\textit{reserved}} word is shown below:
@@ -144,7 +176,7 @@ The data format of the \textbf{\textit{reserved}} word is shown below:
     \begin{tabular}{|W{1.275cm}|W{12.325cm}|}
       \hline
       3 bits	& 29 bits\\
-      "011"	& reserved\\
+      "000"	& reserved\\
       \hline
     \end{tabular}
   \caption{The data format of the \textit{RESERVED} word.}
diff --git a/trb3/TdcSlowControl.tex b/trb3/TdcSlowControl.tex
index 9faa1f2..3d0e649 100644
--- a/trb3/TdcSlowControl.tex
+++ b/trb3/TdcSlowControl.tex
@@ -166,7 +166,9 @@ A set of control registers are assigned in order to access the basic controls, e
 				&					& 31-24	& reserved\\ \hline
       \multirow{2}{*}{0x8f}	& \multirow{2}{3.5cm}{Release Number}	& 23-0	& Number of release signals sent\\
 				&					& 31-24	& reserved\\ \hline
-      \multirow{3}{*}{0x90}	& \multirow{3}{3.5cm}{Channel Scaler}	& 23-0  & Number of hits detected by a channel. Channel number is controlled with register 0xc4\\
+      \multirow{3}{*}{0x90}	& \multirow{3}{3.5cm}{Readout Time}	& 23-0  & Total time length, that the readout occured (with granularity of 10~ns)\\
+				&					& 31-24	& reserved\\ \hline
+      \multirow{3}{*}{0x91}	& \multirow{3}{3.5cm}{Channel Scaler}	& 23-0  & Number of hits detected by a channel. Channel number is controlled with register 0xc4\\
 				&					& 31-24	& reserved\\ \hline
     \end{tabularx}
   \caption{The status registers of the TDC. (Continue)}
-- 
2.43.0