addition of how to read gateware version in Section~\ref{sec:reprog-bitstreams}\\
22-01-2015 & 2.0 & Added changes for V3 front module boards, sections on advanced diagnostics and
referred to gateware guide for specific gateware versions in the Memory Map Appendix \\
15-12-2017 & 3.0 & Added changes for V4 front module boards\\
\hline
\end{tabular}
}
...
...
@@ -123,34 +124,65 @@ work, see \\
\section{Introduction}
\label{sec:intro}
CONV-TTL-RS485 is an open hardware design \cite{ohwr} intended for replicating TTL and RS-485
pulses, or for timing distribution. The main features of the board are:
CONV-TTL-RS485 is an open hardware design \cite{ohwr} intended for replicating TTL, RS-485 and optical
pulses. The main application for this system at CERN would be for General Machine Timing (GMT) frame
distribution. The main features of the board are:
\begin{itemize}
\item VME64x form-factor
\item Possibility to use as timing repeater card
\item Six independent pulse replication channels, each channel capable of replicating
\item Possibility to use two supported Rear Transition Modules (RTMs) at the back
\begin{itemize}
\item\textbf{CONV-TTL-RS485-RTM-DB9}\cite{conv-ttl-rtm-rs485-db9-ohwr} 2-Channel, RS-485 signal repeaters, each with 1 input and 5 outputs. This RTM uses D-Sub9 connectors.
\item\textbf{CONV-RS485-OPT-RTM}\cite{conv-rs485-rtm-opt-ohwr} 3-Channel Optical outputs each with 1 input and 2 outputs. This RTM uses ST connectors.
\textit{Note: A design exists with 6-Channel RS-485 outputs with LEMO 0S (2-pin)
connectors, each with one input and 3 outputs.
\textbf{However this design is no longer supported and no productions have
been made of this configuration}. Therefore it will not be discussed further in this document.}
\end{itemize}
\item Independent pulse replication channels, each channel capable of replicating
\begin{itemize}
\item TTL to TTL
\item With CONV-TTL-RS485 motherboard - 6 Channels with:
\begin{itemize}
\item TTL to TTL
\item TTL-BAR to TTL-BAR
\end{itemize}
\item Four general-purpose inverter channels, for conversion from TTL to TTL-BAR and vice versa
\item CONV-TTL-RS485 motherboard with CONV-TTL-RTM-RS485-DB9 board - 2 Channels with:
\begin{itemize}
\item TTL to RS-485
\item TTL-BAR to TTL-BAR
\item TTL-BAR to RS-485
\item RS-485 to TTL
\item RS-485 to TTL-BAR
\item RS-485 to RS-485
\end{itemize}
\item CONV-TTL-RS485 motherboard with CONV-RS485-OPT-RTM board - 3 Channels with:
\begin{itemize}
\item TTL to Optical
\item TTL-BAR to Optical
\item Optical to TTL
\item Optical to TTL-BAR
\item Optical to Optical
\end{itemize}
\end{itemize}
\item Four general-purpose inverter channels, for conversion from TTL to TTL-BAR and viceversa
\item Each TTL and inverter channel has 50~$\Omega$ input termination
\item Each TTL and inverter channel capable of driving 50~$\Omega$ load
\item Each RS-485 channel capable of driving up to 256 nodes
\item Each RS-485 channel contains lack of signal detection logic
\item Each RS-485 channel has optional input or output 100~$\Omega$ termination
\item Diagnostics
\begin{itemize}
\item converter board ID
\item hardware version
\item gateware version
\item state of on-board switches and RTM detection lines
\item state of on-board switches and RTM detection/ID lines
\item line state at board input
\item input pulse counters
\item input pulse counters for front and rear pulses (TTL or RS-485/optical)
\item input pulse time-stamping with dedicated per-channel latest timestamp
readout
\item manual pulse triggering
...
...
@@ -163,10 +195,14 @@ pulses, or for timing distribution. The main features of the board are:
\end{itemize}
Pulse conversion is obtained by combining the CONV-TTL-RS485 front module (FM) board
with a CONV-TTL-RTM rear-transition module (RTM) together with an attached
CONV-TTL-RTM-RS485 piggyback board, as shown in Figure~\ref{fig:conv-sys-bd}.
with of the two rear-transition modules (RTM), as shown in Figure~\ref{fig:conv-sys-bd} for the D-Sub9 vesion of the RTM.
In this case, a pulse on a channel's input on any side (TTL on the FM side or RS-485 on the
RTM side) is replicated on both the FM and the RTM outputs for the channel.
RTM side) is replicated on both the FM and the RTM outputs for the channel.\\
\emph{\textbf{Note that this motherboard can support RTMs with up to 6 RS-485 channels,
with typically one input port and three outputs. However the custom RTM CONV-TTL-RS485-RTM-DB9, with only 2
RS-485 channels, each having 1 input and 5 outputs, using D-Sub9 connectors, is
The rear panel of the compatible RTM boards are shown in Figures~\ref{fig:rear-panel-db9}
and~\ref{fig:rear-panel-db9}.
For the CONV-TTL-RTM-RS485-DB9, the rear panel consists of the
input and output connectors, as well as pulse status LEDs for each RS-485 pulse channels. An RS-485
pulse at the input connector of a channel is passed through the FPGA and regenerated at the five outputs
of the same channel in RS-485 level, as well as in TTL level at the output connector of the corresponding
TTL channel on the front panel.
With the optical version of the RTM, a single column of 9 ST connectors,
offering 3 I/O channels each with 1 input and 2 outputs, in addition to a pulse status LED, see Fig.~\ref{fig:rear-panel-db9}. For this board, optical pulses are received and transmitted using appropriate optical transceivers. These optical signals are then translated to RS-485 and sent on to the system motherboard through the VME P2 connector. From then on, the signal is treated on the motherboard in the same way as one coming from the copper RTM. The hardware guide~\cite{conv-rs485-opt-rtm-hwg} for this specific RTM contains further details on its hardware implementation.
