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trigger [2013/12/11 16:16] pereira [Time stamping] |
trigger [2013/12/26 13:20] pereira [Trigger] |
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- | The main purpose of the trigger is to implement a coincidence between the S800 focal-plane fast timing scintillator [[Detectors# | + | ====== Trigger ====== |
- | The trigger logic is implemented in a LeCroy 2367 Universal Logic Module (ULM) by means of its XC4000E Xilinx FPGA. The main motivations for implementing the trigger logic in an FPGA driven module are the following: | + | |
+ | * [[Trigger# | ||
+ | * [[Trigger# | ||
+ | * [[Trigger# | ||
+ | * [[Trigger# | ||
+ | * [[Trigger# | ||
+ | * [[Trigger# | ||
+ | * [[Trigger# | ||
+ | * [[Trigger# | ||
+ | * [[Trigger# | ||
+ | * [[Trigger# | ||
+ | * [[Trigger# | ||
+ | * [[Trigger# | ||
+ | * [[Trigger# | ||
+ | * [[Trigger# | ||
+ | |||
+ | |||
+ | The main purpose of the trigger is to implement a coincidence between the S800 focal-plane [[Detectors# | ||
+ | |||
+ | The trigger logic is implemented in a {{: | ||
- Simplify cabling and setup of the trigger | - Simplify cabling and setup of the trigger | ||
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The S800 trigger from the [[Detectors# | The S800 trigger from the [[Detectors# | ||
- | + | ===== Trigger | |
- | ===== Trigger | + | |
The trigger schematic is shown on the Graphical User Interface (GUI) displayed in the figure below. | The trigger schematic is shown on the Graphical User Interface (GUI) displayed in the figure below. | ||
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- | The time stamp module is implemented in a XLM72 (SpartanXL) FPGA. The schematics of the firmware is available {{: | + | The time stamp module is implemented in a XLM72 (SpartanXL) FPGA. The schematics of the firmware is available {{: |
- | + | ||
- | {{: | + | |
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The clear can be done via software as well, and is usually done that way. | The clear can be done via software as well, and is usually done that way. | ||
- | Below is the Verilog | + | The [[Verilog Time stamping|Verilog file]] contains |
- | ........ | + | |
- | ........ | + | |
- | + | ||
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====== Begin sequence ====== | ====== Begin sequence ====== | ||
- | The internal " | + | The internal " |
- | The data acquisition begin sequence of the trigger module is the following: | + | The data acquisition begin sequence of the trigger module is the following: |
- | reset time stamp counter to 0 | + | |
- | reset trigger register to 0 | + | |
- | after all modules in all crates have been initialized, | + | |
- | after a preset delay of 200 to 300 microseconds, | + | |
- | + | ||
- | The last step of the begin sequence allows enough time for the CCUSB crate controller to switch from its interactive mode to data acquisition mode. The end sequence script executed at the end of a run sets the " | + | The last step of the begin sequence allows enough time for the CC-USB |
====== Scalers and dead time ====== | ====== Scalers and dead time ====== | ||
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In addition, scalers are connected to the raw and live trigger signals. For the determination of the dead time, both a free running and vetoed 10 kHz pulser signal are also connected to scalers. This is the preferred method because the pulser is not subject to possible double triggering effects like the raw trigger. | In addition, scalers are connected to the raw and live trigger signals. For the determination of the dead time, both a free running and vetoed 10 kHz pulser signal are also connected to scalers. This is the preferred method because the pulser is not subject to possible double triggering effects like the raw trigger. | ||
+ | The list below is a direct copy of the scaler description file for the s800. This file maps channel names to channel numbers, and in addition determines the layout. | ||
+ | |||
+ | ^ Channel name ^ Channel number ^ Channel name ^ Channel number | | ||
+ | | Live.Trigger | ||
+ | | Live.Clock | ||
+ | | S800.Source | ||
+ | | Second.Source ^ 1 | Second.Trigger ^ 8 | | ||
+ | | Ext1.Source | ||
+ | | Ext2.Source | ||
+ | | Coinc.Trigger ^ 5 | ^ | | ||
+ | | E1.Up ^ 16 | E1.Down | ||
+ | | E2.Up ^ 18 | E2.Down | ||
+ | | CRDC1.Anode | ||
+ | | TPPAC1 | ||
+ | | OBJ.Scint | ||
+ | | TAR.Scint | ||
+ | | S800.Source | ||
+ | | S800.Source | ||
+ | | S800.Source | ||
+ | | Hodo.OR | ||