add few words about backplane

diff --git a/trb3/Trb3scBasics.tex b/trb3/Trb3scBasics.tex
index ae9e70f0cec29932dc63addadd0f07e726d80971..dd1073a35d9715ac535443f9315afa07e5dc2afc 100644 (file)
--- a/trb3/Trb3scBasics.tex
+++ b/trb3/Trb3scBasics.tex
@@ -143,3 +143,12 @@ On the backplane, the AC coupling of the trigger signals needs to be removed as
   \item [C21, C22, C24, C25] Replace by 0R (AC coupling for trigger signals)
   \item [R8, R9, R10, R11] Replace by proper 100 Ohm termination (AC coupling for trigger signals)
 \end{description*}
+
+
+\clearpage
+\section{Trb*sc backplane}
+Both Trb3sc and Trb5sc can be mounted in a 19 inch, 3HU crate. A central master module can be used to control up to 9 peripheral boards. All communication between boards, power, clock, reference time distribution and trigger collection are included on the backplane.
+
+The backplane can be equipped with a DCDC power module for convenient power supply. There are two RJ-45 connectors to connect reference time and external clock signals. Two switches control the source of the distributed signals: Either the RJ-45 connector on the backplane or from the master module. (NB: Make sure you don't build a "clock loop" If the master takes its clock from the backplane and the backplane distributes the clock from the master the setup won't work. This can be seen from the white LED on the master blinking slowly. 
+
+The master module must be a Trb3sc with a dedicated "Master AddOn" that routes signals from its AddOn connector to the right half of the backplane.