
% ===============================================================================
% Purpose: Hardware design of the AIDA mini-TLU
% Author: Alvaro Dosil
% Created on: 2013-03-13
% ===============================================================================

\section{Hardware design}
\label{sec:Hardware design}

The AIDA mini-TLU consist of a Xilinx Spartan 601 evaluation kit, attached to a 
connection card by its FMC-LPC connector. The evaluation kit is a cheap solution
for the mini-TLU. It provides all the features needed with at cheaper cost than a 
built-in design. Some of the key features of the sp601 evaluation kit are showed in 
Table \ref{tab:sp601_features}.

\begin{table}[t]
\centering
\begin{tabular}{| l | l|}

\hline
\multirow{3}{*}{Clocking} &  Internal 200 MHz oscillator \\
 & Socket for a single-ended user oscillator \\
 & SMA connectors \\ \hline
 
Communication & 10/100/1000 Tri-Speed Ethernet PHY \\ \hline

\multirow{2}{*}{Expansion connectors} & FMC-LPC connector (68 se. or 34 diff. user defined signals) \\
 & 8 User I/O (Digilent 2x6 Header) \\ \hline

Display & 4X LEDs \\ \hline

\multirow{2}{*}{Control} & 4X Push Buttons \\
 & 4X DIP Switches \\ \hline
 
\end{tabular}
\caption{Key features of the Xilinx Spartan 601 evaluation kit}
\label{tab:sp601_features}
\end{table}

The second part of the AIDA mini-TLU is the connection card. This card has been designed specifically for
this purpose. The mini-TLU have the next connections plugs, which are also indicated schematically in Figure 
\ref{fig:connections}:

\begin{itemize}
  \item 4 Trigger input: Lemo single-pole size-00
  \item Clock I/O: Lemo two-pole size-00
  \item 1 DUT: RJ45(4 differential signals)
  \item 2 DUT: HDMI (5 differential signals)
  \item 1 Ethernet connection (copper or optical)
\end{itemize}

\begin{figure}
  \centering
    \includegraphics[scale=0.35]{figs/miniTLU_box.png}
  \caption{AIDA mini-TLU connections.}
  \label{fig:connections}
\end{figure}


The device under test signals are connected to the TLU via one RJ45 and two HDMI connectors. The two connections have 
the same signals, but only the RJ45 is backward compatible with the JRA1 Trigger Logic Unit.

\subsection{RJ45 connector}
The AIDA mini-TLU has one RJ45 connector, compatible with the JRA1 TLU. This connection provides 4 LVDS signals. A detailed 
description of the signals is indicated in Table \ref{tab:RJ45_signals}. Pin out at the mini-TLU:

\begin{enumerate}
 \itemsep0em 
 \item DUT\_CLOCK-
 \item DUT\_CLOCK+
 \item BUSY-
 \item CONTROL-
 \item CONTROL+
 \item BUSY+
 \item TRIGGER-
 \item TRIGGER+
\end{enumerate}

Connector pins numbering is illustrated in Figure \ref{fig:RJ45_signals}.
\begin{figure}
  \centering
    \includegraphics[scale=0.2]{figs/RJ45.png}
  \caption{8P8C (RJ45) connector pin-out}
  \label{fig:RJ45_signals}
\end{figure}

\begin{table}[t]
\centering
\begin{tabular}{|l|l|c|}
\hline
Name & Description & Signal type \\ \hline \hline
Clock & Input/Output: Clock from/to DUT & LVDS \\ \hline
Busy & Input: Busy signal from DUT & LVDS \\ \hline
Control & Output: Shutter, spill-on, power-cycling & LVDS \\ \hline
Trigger & Output: Trigger signal to DUT & LVDS \\ \hline
\end{tabular}
\caption{RJ45 signal details}
\label{tab:RJ45_signals}
\end{table}


\subsection{HDMI connectors}
The AIDA mini-TLU has two HDMI connectors, providing 1 LVTTL and 5 LVDS signals each, as indicated in \ref{fig:HDMI_signals}. 
The pin out is the following:
\begin{enumerate}
 \itemsep0em 
 \item CLOCK-
 \item GND
 \item CLOCK+
 \item CONTROL+
 \item GND
 \item CONTROL-
 \item BUSY+
 \item GND
 \item BUSY-
 \item SPARE+
 \item GND
 \item SPARE-
 \item UNCONNECTED
 \item HDMI\_POWER\_ENABLE
 \item TRIGER+
 \item TRIGER-
 \item GND
 \item UNCONNECTED
 \item UNCONNECTED
\end{enumerate}

Connector pins numbering is illustrated in Figure \ref{fig:HDMI_signals}.
\begin{figure}
  \centering
    \includegraphics[scale=0.5]{figs/HDMI_Connector_Pinout.png}
  \caption{Type A receptacle HDMI pin-out}
  \label{fig:HDMI_signals}
\end{figure}

\begin{table}[t]
\centering
\begin{tabular}{|l|l|c|}
\hline
Name & Description & Signal type \\ \hline \hline
Clock & Output: Clock to DUT & LVDS \\ \hline
Busy & Input: Busy signal from device & LVDS \\ \hline
Control & Output: Shutter, spill-on, power-cycling & LVDS \\ \hline
Trigger & Output: Trigger signal to DUT & LVDS \\ \hline
Spare & Input: General purpose Input & LVDS \\ \hline
HDMI\_POWER\_ENABLE & Output: HDMI power enable & LVTTL \\ \hline
\end{tabular}
\caption{HDMI signals details}
\label{tab:HDMI_signals}
\end{table}

Each of this cables can control one device and, since the mini-TLU only provides two HDMI and one RJ45 connectors, we will need 
a method to spread the signals. We will use an HDMI fannout. This gadget is a 1:8 fanout, providing 
three differential pairs having 1:8 fanout and two differential pair having a 8:1 fan-in. The fanout schematic is 
indicated in Figure \ref{fig:fannout}.



\begin{figure}
  \centering
    \includegraphics[scale=0.5]{figs/FANOUT_BLOCK.png}
  \caption{Fanout to spread the signals from the mini-TLU to many devices.}
  \label{fig:fannout}
\end{figure}