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--- event_filter [2015/11/01 08:25]
pereira [Mesytec TDC (MTDC) packet]
+++ event_filter [2016/03/16 15:37]
pereira
@@ Line 1: / Line 1: @@
-====== Event Filter (S800 Filter) ======
+====== S800 data format from Event Filter (S800 Filter) ======
+This page describes the data format assembled by the S800 filter. The data is written in a series of 16-bit unsigned integers, subsequently referred to as ''words''. This format is suitable for the output of most of the modules presently used in the S800, and in the case where 32 bit integers are needed, the proper unpacking procedures will be given.
+===== General packet structure =====
+All data is written using the concept of "packets". The format of a packet is:
+^ Length ^ Packet Tag ^ Packet Data |
+Length: a count of the number of words in the packet, inclusive of the length word itself
+Packet Tag: a predefined integer indicating the type of data found in the Packet Data
+Packet Data: the data themselves. These can be data read from the modules or a sub packet. Sub packets have identical structure to main packets. Using this format all data can be placed in nested packets, and coding decisions on how to unpack the Packet Data can be made by examination of the preceding Packet Tag. Packets (including sub packets) can also be skipped by jumping ahead Length words in the buffer.
-The trigger bits words indicates which bits were set during the event. The encoding of the bits is the following:
 In this section, each 16-bit word sent by the Filter is described by a 16x3-table diagram. The first row includes the value, either in decimal or hexadecimal format, or a descriptive note. The second row shows the value in binary ("X"s are used to describe arbitrary values that vary from event to event). The last row shows the bit number.
@@ Line 642: / Line 655: @@
-^^^^^  hit  ^^^^ channel ^^^^^^^|
+^   ^^^  hit  ^^^^^ channel ^^^^^^^|
 | 0 | 0 | 0 | X | X | X | X | X | X | X | X | X | X | X | X | X |
 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
@@ Line 651: / Line 664: @@
 | X | X | X | X | X | X | X | X | X | X | X | X | X | X | X | X |
 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
+===== Versioning system =====
+ATTENTION: This section needs to be updated!!!!!
+The detectors installed in the S800 and the data to be read from them often changes with the differing requirements of each experiment. This in turn impacts the details of the data format, and requires the use of a version number in order to be backward compatible. Subsequent changes to the S800 data acquisition will increment the version number of the data format and new configurations will be reflected in new packet tags. Documentation for these changes will be given here, in links accessible from the following table. The current version of the data format is indicated with a star.
+^ S800_VERSION ^ Notes ^ Current Version |
+| [[S800_VERSION 0x0004|0x0004]] | Last version using the SBS readout system, up to end December 2011 | |
+| [[S800_VERSION 0x0005|0x0005]] | First version to use the VM/CC-USB parallel readout system, beginning January 2012 |  |
+| [[S800_VERSION 0x0006|0x0006]] | The S800_GALOTTE_PACKET is added for the Galotte MCP Object box detector | * |

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