CSM0 Output Format/Options

R. Ball

July 24, 2000

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Basic Options

n Current AMT-0 output limited to standard type of

clock and data pairs.

n Many other serial data options still possible.

– Search window size, etc.

– Data type (edges or combined time over threshold)

n TDC data type sent as first hex character of the

data word

– CSM MUST

be programmed to match these

n TDC headers/trailers indicate event boundaries

and must be present

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AMT-0 Data Stream

n Upon triggering, AMT-0 sends TDC header word

n Next sends all hits found within match window

– Sends in JTAG specified format

– TDC channel is encoded within the word

– TDC number is known by its RJ45 input jack

n Last of all the TDC trailer word is sent

n For isolated (in time) triggers, all headers arrive at

once at the CSM

n Trailers straggle in depending on number of hits

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VME FIFO Event Data

n CSM header is the first word of the event

– Written when event trigger fetched from fifo

– Hex value = 0x59EEEBBB, EEE=EVID, BBB=BCID

n TDC headers (optional) for all active channels

– Leading hex value = 0xaN, N=position on JTAG chain

n TDC data of all active types (JTAG specified)

– Nine bits of TDC number/channel replaced by CSM

w TDC 0-15 unchanged

w TDC 16 maps to TDC 0,1,2, channels 24-31

w TDC 17 maps to TDC 4,5,6, channels 24-31

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VME FIFO Event Data (2)

n TDC data of an unknown type written without

change.

n TDC trailers (optional) for all active channels

– These may be mixed with TDC data of all types

– Leading hex value = 0xcN

n CSM trailer is the last word of the event

– Written when event trigger fetched from fifo

– Hex value = 0x5XEEEBBB, EEE=EVID, BBB=BCID

– X=b if event OK, X=d if error occurs

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VME FIFO Event Data (3)

n Four bit word types (leading hex character) used

by CSM determined by value in CSM register 3

– Default setting of register is 0x535A4C

n Following the CSM trailer, the EVID/ WordCount

register is written with event information

n “Complete Event Ready” bit is set when valid

EVID/WC value is ready.

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Readout Sequence

n Check if “Complete Event Ready” bit is set

n Read one word from EVID/WC fifo

n Read WC words from VME FIFO

– Read one extra word (a zero) if PDT used instead of

block transfer.

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MiniDAQ Data Record Format

n Data packed into (max) 1024 word buffers on disk

n Eleven word header at start of buffer

– 1. Total length of buffer in words

– 2. Run Number

– 3. Buffer number

– 4 and 5 Reserved

– 6. Number of triggers packed into this buffer

– 7. Number of data words in buffer (excludes header)

– 8. ASD threshold

– 9 and 10 = zero

– 11. Number of data words in buffer (excludes header)

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MiniDAQ Data Record Format

n Words 12 to buffer’s end are data records.

n Data Record content

– 1. EVID/WC register content

– 2-end. Data words from the VME FIFO

n Buffer packing in record ends if too few words

remain for a complete event

– #define MIN_AVAIL 256

n End of run forces buffer flush to disk

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