The main inputs for the uGT come from the calorimeter and muon trigger processors via fast optical links, but in addition, the uGT has to handle legacy electronics inputs and External Conditions. These signals are basic binary input signals from less complex trigger sources which are arriving over RJ45 connectors in the Low Voltage Differential Signaling (LVDS) standard as electric signals. A patch-panel was designed which transforms respectively eight RJ45 connectors into one VHDCI connector to get all signals into the LVDS input cards. These signals are then forwarded to the custom AMC502 module.
Figure: External condition hardware overview.
The LVDS input card is based on Xilinx Kintex-7 technology and has the dimensions of a full height and double width AMC module. The concept is based on modularity, which supports increasing the number of external conditions to be used. Each card has two FMC (FPGA Mezzanine Card) slots for extending the module's functionality. The idea of the LVDS input card consists of an FMC module with two VHDCI connectors on it, which equals 16 RJ45 connectors. E.g. for 128 external conditions, we need two LVDS input cards each with an FMC module with two VHDCI connectors. The output to the uGT can be realized either via optical fibers, which would require a second FMC module with optical transceivers on it, or via backplane connection, which serves as backup solution. A draft of the External Condition data flow is illustrated in figure.