Document type: Title: Revision date: Revision:User's Manual (MUT) Mod. V1724 8 Channel 14bit - 100MS/s Digitizer 06/11/2007 7NPO: Filename: Number of pages: Page:00103/05:V1724x.MUTx/07 V1724_REV7.DOC 63 24N LOC = 0 means “default size events”, i.e. the number of memory locations is themaximum allowed.N LOC = N1, with the constraint 0⋅N1samples.3.3.5. Event structureAn event is structured as follows:− identifier (Trigger Time Tag, Event Counter)− samples caught in the acquisition windowsThe event is stored in the board memories and can be readout via VME; data format is32 bit long word, therefore each long_word contains 2 samples.The event format is the following:31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0EVENT SIZECHANNEL MASKTRIGGER TIME TAG101 0reservedEVENT COUNTERreservedSAMPLE [1] – CH[0] SAMPLE [0] – CH[0]SAMPLE [3] – CH[0] SAMPLE [2] – CH[0]SAMPLE [N-1] – CH[0] SAMPLE [N-2 ] – CH [0]SAMPLE [1] – CH[1] SAMPLE [0] – CH[1]SAMPLE [3] – CH[1] SAMPLE [2] – CH[1]SAMPLE [N-1] – CH[1] SAMPLE [N-2 ] – CH [1]HEADER DATA CH0 DATA CH1SAMPLE [1] – CH[7] SAMPLE [0] – CH[7]SAMPLE [3] – CH[7] SAMPLE [2] – CH[7]SAMPLE [N-1] – CH[7] SAMPLE [N-2 ] – CH [7]DATA CH7BOARD-ID0 00 00 00 00 00 00 00 00 00 00 00 0 0 00 00 00 00 00 0PATTERNTable 3.2 : Event OrganizationHeaderIt is composed by four words, namely:− Size of the event (number of 32 bit long words)− Board ID (GEO); a 16 bit pattern, latched on the LVDS I/O as one trigger arrives (see§ 4.25); Channel Mask (=1: channels participating to event; ex CH5 and CH7participating →Ch Mask: 0xA0, this information must be used by the software toacknowledge which channel the samples are coming from)− Event Counter: It is the trigger counter; it can count either accepted triggers only, orall triggers (see § 4.17).− Trigger Time Tag: It is a 32 bit counter (31 bit count + 1 overflow bit), which is reseteither as acquisition starts or via front panel Reset signal (see § 3.8), and isincremented at each sampling clock hit. It is the trigger time reference.SamplesStored samples; data from masked channels are not read.
