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Pixie-4 Programmer`s Manual

1. 33 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved 3 3 Access spectrum memory or list mode data 3 3 1 Access spectrum memory The MCA spectrum memory is fixed to 32K words 32 bits per word per channel residing in the external memory Therefore the starting address of the MCA spectrum in the external memory for Channel 0 1 2 and 3 will be 0x00000000 0x000080000 0x00010000 0x00018000 respectively The reading out of the spectrum memory to the host is through the PCI burst read at rates over 100 Mbytes s The spectrum memory is accessible even when a data acquisition run is in progress The following code is an example of how to start a MCA run and read out the MCA spectrum after the run is finished An Example Code Illustrating How to Access MCA Spectrum Memory 532 retval U8 direction modnum channum U32 User Data 131072 an array for holding the MCA spectrum data of 4 channels direction 0 download modnum 0 Module 0 channum 0 Channel 0 start a MCA run retval Pixie Acquire Data 0x1301 User Data modnum if retval 0 Error handling wait for 30 seconds Sleep 30000 stop the MCA run retval Pixie Acquire Data 0x3301 User Data modnum if retval lt 0 Error handling save MCA spectrum to a file retval Pixie Acquire Data 0x5301 User Data C XIA Pixie4 MCA Data0001 bin modnum if
2. 3 1 1 Initialize Global Variables As discussed in Section 2 we assume that three global variable arrays have been defined System Parameter Values Module Parameter Values and Channel Parameter Values For these three global variable arrays three corresponding global name arrays are defined System Parameter Names Module Parameter Names and Channel Parameter Names respectively Table 3 5 lists the names contained in each of these name arrays The API uses search functions to locate a variable value by name at run time The file names for the DSP and firmware files have to be copied to the internal array Boot File Name List Table 3 2 lists the names and order of files needed to initialize the Pixie 4 modules Table 3 2 File Names in All Files Uc EEE KE CAXIA VPixie4 Firmware Nyspixie revC bin Communication FPGA configuration Pixie 4 Rev C D E CAXIA Pixie4 Firmware pixie bin Signal processing FPGA configuration Pixie 4 3 CAXIA Pixie4 DSPWPXIcode bin DSP executable binary code for the Pixie 4 CAXIA Pixie4 Configuration default set Settings file CAXIAVPixie4 DSPWP500e var File of DSP I O variable names C XIA Pixie4 DSP PXIcode st File of DSP memory variable names for the Pixie 500 and the Pixie 4 bin Pixie 500 Rev B Pixie 500 91 CAXTA P500eSW Firmware pixieS00e bin FPGA configuration Pixie 500 Express Pixie 500 Pixie 500 Express for the Pixie 500 Express 28 Pixie 4
3. An array containing the names to be downloaded U8 Name A string indicating the type of names file or variable names to be downloaded Description Use this function to download the file or variable names from the host user interface to the Pixie API The API needs these file names so that it can read the Pixie hardware configurations from the files stored in the host computer and download these configurations to the Pixie The variable names are used by the API to obtain the indices of the DSP variables when the API converts user variable values into DSP variable values or vice versa Note Since variable names are now defined in the C library itself this function is only required for the Igor and LabView host interfaces Other C based interfaces usually do not require it see the sample programs for examples on how to specify the file names in the library array Boot File Name List Parameter description Names is a two dimensional string array containing either the file names or the variable names The API will know which type of names is being downloaded by checking the other parameter Name 1 ALL FILES This indicates we are downloading boot files names In this case Names is a string array which has N BOOT FILES elements Currently N BOOT FILES is defined as 16 The elements of Names are the names of FPGA files DSP executable code binary file DSP I O parameter values file DSP code I O variable names file and DS
4. N A NA N A NA N N A C LIBRARY BUILD N A KEEP CW Read Write N A SLOT WAVE Read Write N A SLOT WAVE is followed by up to 16 slot entries Entries are addressed as SLOT WAVE N Table 3 5b Descriptions of Module Global Variables in Pixie 4 Removed variables are erossed out MODULE NUMBER MODULE CSRA MODULE CSRB MODULE FORMAF ReadAWrite N A MODFORMAT MAX EVENTS COINCIDENCE PATTERN ACTUAL COINCIDENCE WAIT MIN COINCIDENCE WAIT SYNCH WAIT IN SYNCH RUN TYPE FILTER RANGE MODULEPATTERN NNSHAREPATTERN Read Write DBLBUFCSR Read Write MODULE CSRC Read Write BUFFER HEAD LENGTH EVENT HEAD LENGTH CHANNEL HEAD LENGTH Read only CHANHEADLEN OUTPUT BUFFER HENGER NUMBER EVENTS RUN TIME RUNTIMEX A B C 32 Pixie 4 Programmer s Manual V3 11 XIA 2014 All rights reserved TOTAL TIME BOARD VERSION SERIAL NUMBER DSP RELEASE DSP BUILD FIPPI ID SYSTEM ID XET DELAY PDM MASKA Read Write PDM MASKB Read Write PDMMASKB PDM MASKC Read Write PDMMASKC Table 3 5c Descriptions of Channel Global Variables in Pixie 4 EMIN ReadAWrte N A ENERGYEOW INPUT COUNT RATE Read only cps FASTPEAKSX A B C LIVETIMEX A B C FTDTX A B C FAST PEAKS FASTPEAKSX A B C OUTPUT COUNT RATE Read only cps NOUTX A B LIVETIMEX A B C NOUT Read only NOUTX A B GATE RATE Read only cps GCOUNTX A B LIVETIMEX A B C
5. 13 3ns TOTALTIMEX 64K 3 TOTALTIMEA 64K 2 TOTALTIMEB 64K TOTALTIMEC GSLTTIMEA GSLTTIMEB GSLTTIMEC Removed 65 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved NUMEVENTSX NUMEVENTSA NUMEVENTSB Number of valid events serviced by the DSP Number of Events NUMEVENTSX 64K 2 NUMEVENTSA 64K NUMEVENTSB DSPERROR This variable reports error conditions 0 NOERROR no error 1 RUNTYPEERROR unsupported RunType 2 RAMPDACERROR Baseline measurement failed 3 EMERROR writing to external memory failed SYNCHDONE This variable is set to 1 after the DSP comes out of its synchronization loop when a run start request was issued with SYNCHWAIT 1 TEMPERATURE reserved BUFHEADLEN At the beginning of each run the DSP writes a buffer header to the list mode data buffer BUFHEADLEN is the length of that header Currently BUFHEADLEN is 6 in runtask 0x10 and 32 in runtask 0x400 but this value should not be hardcoded it should be read from the DSP to ensure upgrade compatibility EVENTHEADLEN For each event in the list mode buffer or the level 1 buffer there is an event header containing time and hit pattern information EVENTHEADLEN is the length of that header Currently EVENTHEADLEN is 3 in runtask Ox 10 and 0 in runtask 0x400 but this value should not be hardcoded it should be read from the DSP to ensure upgrade compatibility CHANHEADLEN For each channel that has been rea
6. 43 Pixie 4 Programmer s Manual V3 11 XIA 2014 All rights reserved RunTask 1024 0x400 requests a standard list mode run for Pixie 500 Express The scope of event processing includes computing energies to 16 bit accuracy and performing pulse shape analyses for improved energy resolution and better time of arrival measurements 32 words of results including time of arrival energy XIA pulse shape analysis user pulse shape analysis etc and waveforms are written into the SDRAM FIFO for each channel Igor controls Run Type in the Run Control tab C global RUN TYPE The C library checks for the RUNTASK to be of the form 0xONON with 0 lt N lt 4 ControlTask to apply change none CONTROLTASK Use this variable to select a control task Consult the control tasks section of this manual for detailed information The control task will be launched when you issue a run start command with RUNTASK 0 See section 4 5 for a list of acceptable values Igor controls none C global none ControlTask to apply change none MAXEVENTS The module ends its run when this number of events has been acquired In the Pixie Viewer the maximum value for MAXEVENTS is automatically calculated and applied when a run mode is chosen from the run type pulldown menu The calculation is based on the RUN TYPE the TRACELENGTH and CHANCSRA bit 2 good channel bit using BUFHEADLEN EVENTHEADLEN CHANHEADLEN given by the RUN TYPE and the length of t
7. Read 128K first If run halted because host did not read fast enough and both blocks in external memory are filled DSP will set this bit to indicate host to first read from block 1 staring at address128K else if zero host should first read from block 2 Set by DSP read by host Cleared by DSP at runstart or resume Not recommended for Pixie 4 and Pixie 500 Ignored for Pixie 500 Express Igor controls Radio buttons in the Run Control tab C global DBLBUFCSR ControlTask to apply change 5 U00 Many unused but reserved data blocks have names of the structure Unn Those unused data blocks which reside in the block of input parameters for each channel are called UNUSEDA and UNUSEDB HOSTIODATA A 4 word data block that is used for data I O in some control tasks 48 Pixie 4 Programmer s Manual V3 11 XIA 2014 All rights reserved Igor controls none C global none ControlTask to apply change none PDMMASKA PDMMASKB PDMMASKC reserved XETDELAY If a front panel signal is used as an external fast trigger for the backplane this variable specifies the delay for the auto generated event trigger The event trigger indicates that at least one trigger enabled channel has a valid hit pulse present no pileup so the delay should typically be set to a value slightly larger than the energy filter rise time plus energy filter flat top of the channels to be triggered externally If XETDELAY 0 the front panel signal is ignored
8. wait until run has ended while Pixie Acquire Data 0x4100 User Data DataFile modnum read out the list mode data and save it to a file retval Pixie Acquire Data 0x6100 User Data DataFile modnum if retval 0 Error handling EE if k Nruns break issue RESUME RUN command retval Pixie Acquire Data 0x2100 User Data DataFile modnum if retval 0 Error handling while 1 read out the MCA spectrum and put it to array User Data retval Pixie Acquire Data 0x9001 User Data DataFile modnum if retval 0 Error handling 36 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved An Example Code Illustrating How to Access List Mode Data Pixie 500 Express 532 retval U8 direction modnum channum U32 User Data 131072 an array for holding the MCA spectrum data of Ul6 k Nruns 4 channels char DataFile C XIA Pixie4 PulseShape Data bin direction 0 download modnum 0 Module 0 channum 0 Channel 0 Nruns 10 10 repeated list mode runs k 0 initialize counter start a general list mode run retval Pixie Acquire Data 0x1400 User Data DataFile modnum if retval lt 0 do wait until the while Error handling host buffer has been filled I Pixie Acquire Data 0x40FF User Data DataFile modnum amp 0x4000 save data t
9. 52 trace data for channel 0 1 2 3 use above tracelength to extract 7 Appendix C Double buffer mode for list mode readout Note The double buffer mode is no longer supported existing code can be used as is Traditionally list mode runs acquired one 8K buffer of data at a time stored in DSP memory Later 32 8K buffers were stored in external memory EM for faster readout but the acquisition still stopped as soon as the DSP filled the 32 buffer and only resumed after the host read out the Pixie 4 module s In the new double buffer mode the DSP fills an 8K buffer and transfers it to EM 16 times automatically resuming acquisition after each transfer Buffer fills and transfers are synchronized between modules After the 16 buffer transfer the DSP indicates data is ready then switches to a different block in the external memory and resumes acquisition without waiting for host readout The host can read out the data from the external memory in its own time notify the DSP the memory block is now available again and wait for the next 16 buffers to become available Runs can continue indefinitely unless the host is too slow to read out the memory if the DSP ever fills both blocks it stops the acquisition and waits for readout resume by the host Note that in systems with several modules there are now groups of 16 buffers per module following each other in the output data file not individual buffers In low count rate app
10. Igor controls Trigger Filter Flat Top in the Trigger tab C global TRIGGER FLATTOP ControlTask to apply change 5 PEAKSAMPLE Removed 55 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved PEAKSEP This value governs the minimum time separation between two pulses Two pulses that arrive within a time span shorter than determined by PEAKSEP will be rejected as piled up The recommended value is PEAKSEP PEAKSAMPLE 5 Constraints If PEAKSEP 7128 PEAKSEP PEAKSAMPLE 1 0 lt PEAKSEP PEAKSAMPLE lt 7 Igor controls none C global none ControlTask to apply change 5 FASTTHRESH This is the trigger threshold used by the trigger filter FPGA It is compared to the output of the fast filter if the filter output is greater or equal to FASTTHRESH a trigger is issued For a pulse with a given height the trigger filter output scales with the trigger filter rise time FASTLENGTH i e filter output FASTLENGTH pulse amplitude 4 form factor where pulse amplitude is the amplitude in ADC units as displayed in the oscilloscope and form factor describes the effect of the shape of the pulse during FASTLENGTH For a square pulse form factor 1 for a slow rising or fast decaying pulse form factor will be less than 1 because the amplitude is not constant during FASTLENGTH The threshold value TRIGGER THRESHOLD set in the Trigger tab in Igor is scaled in the C library for FASTLENGTH so that a given value of
11. RunType if retval 0x10 Error handling wait until the run has ended RunType 0x4100 while Pixie Acquire Data RunType dummy dummy start a new list mode run ModNum ModNum 7 Read out the list mode data from all Pixie modules and save to a file RunType 0x6100 20 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved retval Pixie Acquire Data RunType dummy C XIA Pixie4 PulseShape Listdata0001 bin ModNum if retval 0x60 Error handling Read out the histogram data from all Pixie modules and save to a file RunType 0x5100 retval Pixie Acquire Data RunType dummy C XIA Pixie4 MCA Histdata0001 bin ModNum if retval 0x50 Error handling 21 Pixie 4 Programmer s Manual V3 11 XIA 2014 All rights reserved Pixie Set Current ModChan Syntax 532 Pixie Set Current ModChan U8 Module Module number to be set U8 Channel Channel number to be set Description Use this function to set the current module number and channel number Parameter description Module specifies the current module to be set Module should be in the range of O to NUMBER MODUDLES in the System Parameter Values Currently the overall maximum as defined by PRESET MAX MODULES is 17 Channel specifies the current channel to be set Channel should be in the range of O to NUMBER
12. User data 2n Location of channel n s data in file for selected event word number User data 2n 1 length of channel n s trace The remaining array elements are return values User data 8 Trace data of channel 0 followed by channels 1 2 and 3 0x7004 Read Energies of all events Length must be NumEvents of ModNum NumberOfChannels All array elements are return values User data i 4 n energy of channel n for event i 0x7005 Read PSA values of all events Length must be NumEvents of ModNum 2 NumberOfChannels All array elements are return values User data i 2n XIAPSA word of channel n for event i User data i 2n 1 UserPSA word of channel n for event i 0x7006 Read extended PSA values of all events Length must be NumEvents of ModNum 8 NumberOfChannels All array elements are return values User data i 8n Channel Header 0 or 4 5 usually timestamp of channel n for event i 16 bit for Pixie 4 and Pixie 500 32 bit for Pixie 500e User data i 8n 1 Channel Header 1 or 8 energy of channel n for event i User data i 8n 2 Channel Header 2 or 11 XIAPSA of channel n for event i User data 1 8n 3 Channel Header 3 or 10 UserPS A of channel n for event i User data i 8n 4 Channel Header 4 or 12 ExtendedPSA1 of channel n for event i User data i 8n 5 Channel Header 5 or 13 ExtendedPSA2 of channel n for event i User data i 8n 6 Channel Header 6 or 14 ExtendedPSA3 of channel n for event i User data i 8n
13. 7 Channel Header 7 or 15 RealTime High or ExtendedPSA4 of channel n for event 1 Notes Headers 1 7 can be modified by DSP user routine in customized code In Pixie 4 and Pixie 500 standard DSP code Header 7 contains RealTime High word 0x7007 Locate all events Length must be NumEvents of ModNum 3 All array elements are return values User data i 3 Location of event i in file word number User data i 3 1 Location of buffer header start for event i in file User data i 3 2 Length of event i event header channel header traces 0x7008 Read one event Length must be length of selected event 7 36 this is longer than actually used but ensures enough room for channel headers in all runtypes First 3 elements are input values 16 Pixie 4 Programmer s Manual V3 11 XIA 2014 All rights reserved User data 0 Location of selected event in file word number User data l Location of buffer header start for selected event in file User data 2 Length of selected event The remaining array elements are return values User data 3 6 are the tracelengths of channel 0 3 User data 7 6 BHL contain the buffer header corresponding to the selected event User data 7 BHL 6 BHL EHL contain the event header User data 7 BHL ELH 6 BHL EHL 4 CHL are the channel headers for channel 0 3 always 9 words per channel header but in compressed runtypes some entries are User data 7 BHL be invalid HEHL
14. Programmer s Manual V3 11 3 XIA 2014 All rights reserved The non read only variables in the global variable array System Parameter Values also need to be initialized before the API functions are called to start the initialization Table 3 3 lists those global variables and the definition of their allowed values Table 3 3 Initialization of Module Global Values Module Global Names Module Global Definition Default Value The total number of Pixie 4 modules present Range 1 MAX NUMBER MODULES 0 for online analysis AUTO PROCESSLMDATA I for offline analysis no I O with modules 0 to not writing results in a dat file while parsing list mode output data I to write standard dat file during parsing 2 to write extended dt2 file during parsing 13 14 slot XIA 6U chassis 17 14 18 slot NI 3U chassis 62 8 slot PXI PXIe NI chassis 1062Q 0 Channel COINC DELAY is set by user Channel COINC DELAY is automatically adjusted to compensate for difference in energy filter length MAX NUMBER MODULES 7 Select chassis type 7 4 5 6 8 slot chassis KEEP CW Note not yet implemented for Pixie 500 Express Module 0 is s n 110 Module 1 is s n 111 SLOT WAVE Module au is s n 3 1 2 Boot Pixie Modules The boot procedure for Pixie 4 modules includes the following steps First the function Pixie User Par IO should be called to initialize the global value array System Parameter Values The Pixie Boot System
15. SYSTE Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved Pixie Acquire Data Syntax 532 Pixie Acquire Data U16 Run Type Data acquisition run type U32 User data An unsigned 32 bit integer array containing the data to be transferred U8 file name Name of the file used to store list mode or MCA histogram data U8 ModNum The number of the Pixie module Description Use this function to acquire ADC traces MCA histogram or list mode data The string variable file name should always be specified for start stop poll of acquisition runs it is the filename for the data in other cases it is the filename to be processed In rare cases file name can be specified as an empty string The unsigned 32 bit integer array User data is only used for acquiring ADC traces control task 0x84 reading out list mode data or MCA spectra In all other cases User data can be any unsigned integer array with arbitrary size Make sure that User data has the correct size and data type before reading out ADC traces list mode data or MCA spectrum Parameter description Run Type is a 16 bit word whose lower 12 bit specifies the type of either data run or control task run and upper 4 bit specifies actions start stop poll as described below Controltasks are described in detail in section 4 5 Lower 12 bit 0x100 0x101 0x102 0x103 list mode runs Pixie 4 and Pixie 500 0x400 0x201 0x202 0x203 list mode
16. by the assembler linker when creating the executable On power up the DSP code makes these values accessible to the user Note that the addresses may change with every new compilation Therefore your code should never assume to find any given buffer at a fixed address LOUTBUFFER Removed The length of the IO data buffer is always 8192 HARDWAREID ID ofthe system FPGA configuration HARDVARIANT Removed FIFOLENGTH Length of the onboard FIFOs measured in storage locations FIPPIID ID of the FiPPI FPGA configuration FIPPIVARIANT Removed INTRFCID Unused INTRFCVARIANT Removed DSPRELEASE DSP software release number DSPBUILD DSP software build number 67 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved 4 4 Channel output parameters The following channel variables contain run statistics Again the variable names carry the channel number as a suffix For example the LIVETIME words for channel 2 are LIVETIMEA2 LIVETIMEB2 LIVETIMEC2 Channel numbers run from 0 to 3 LIVETIMEX LIVETIMEA LIVETIMEB LIVETIMEC Total live time as measured by the trigger filter FPGA of that channel See the user manual for a description of the measured time Convert the four LiveTime words into a live time using the formula LiveTime LIVETIMEX 64K 3 LIVETIMEA 64K 2 LIVETIMEB 64K LIVETIMEC dt dt 13 3ns 16 for Pixie 4 8ns 32 for Pixie 500 and Pixie 500 Express FASTPEAKSX FASTPEAKSA FASTPEAKSB The number
17. cycles 426 ns May be useful for systems where the detector output shows significant ringing that causes two or more triggers on the same pulse especially those with higher amplitude to avoid these events to be rejected as piled up Gate edge polarity inverted Pixie 4 only If set the GATE Window counter is started at the falling edge of the GATE signal instead of on the rising edge Gate Statistics Pixie 4 only If set run statistics are in GATE mode where all counters except RUN TIME and TOTAL TIME are only active if a GATE or VETO signal is present Essentially requires GATE or VETO to be present for the channel to be counted as live Rejection of pulses by GATE or VETO must be enabled separately If not set livetime and other counters are independent of GATE or VETO GATE or VETO presence is counted separately in GDT only if the module is live GDT counts allowed time Pixie 4 only Invert the GDT counter for GATE or VETO presence If not set GDT counts the 52 Pixie 4 Programmer s Manual V3 11 XIA 2014 All rights reserved time during which pulses would be rejected rejection must be enabled separately If set GDT counts the time during which pulses are allowed Bit 10 No gate pulse Pixie 4 only If set the gate pattern bits in the event hit pattern is simply the status of the gate input at the time of local or group fast trigger If not set the gate pattern bits reflect the coincidence of a delayed and stretc
18. for triggering and neither external fast triggers nor external event triggers are issued to the backplane Currently not implemented for the Pixie 500 Express Constraints XETDELAY 0 XETDELAY lt 65535 Igor controls Validation Delay in the Chassis Setup Panel C global XET DELAY ControlTask to apply change 5 XDATLENGTH Removed USERIN A block of 16 input variables used by user written DSP code 4 2 Channel input variables All channel 0 variables end with 0 channel 1 variables end with 1 etc In the following explanations the numerical suffix has been removed Thus e g CHANCSRAO becomes CHANCSRA etc CHANCSRA The control and status register bits switch on off various aspects of the Pixie 4 operation Bit 0 Respond to group triggers only Set this bit if you want to the acquisition for this channel to be controlled by the distributed group trigger instead of the local trigger for this channel Waveforms are then always captured based on the distributed triggers but channel time stamps are based on either local or group triggers local option bit 13 below and energies are based on local triggers The group trigger is a combination of 49 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 Bit 7 Bit 8 Bit 9 triggers from all channels enabled for triggers bit 4 Bit 0 should be set for all channels in the
19. group trigger enabled or not to ensure the same routing delays for trigger distribution in all channels Note To distribute group triggers between modules bit 2 in the variable MODCSRA has to be set as well reserved Good channel Only channels marked as good will contribute to spectra and list mode data Ignored for Pixie 500 Express Read always Channels marked as such will contribute to list mode data even if they did not report a hit This is most useful when acquiring induced signal waveforms on spectator electrodes i e electrodes that did not collect any net charge but only saw a transient induced signal Ignored for Pixie 500 Express Channels set to respond to group trigger will always be recorded based on that trigger Enable trigger Set this bit for channels that are supposed to contribute to an event trigger Trigger positive Set this bit to trigger on a positive slope clear it for triggering on a negative slope The trigger filter FPGA can only handle positive signals The Pixie handles negative signals by inverting them immediately after entering the FPGA GFLT Veto required Set this bit if you want to validate or veto events based on a global external signal distributed over a PXI bussed line named GFLT or Veto When the bit is cleared the GFLT Veto signal is ignored When set the event is accepted only if validated by GFLT Veto To be validated the GFLT veto signal must be a logic 0 at time PEA
20. main energy peak in the spectrum for fixed time intervals Once the MAXWIDTH cut is too tight there will be a loss of efficiency in the main peak Setting MAXWIDTH to such a value that the efficiency loss in the main peak is acceptable will give the best overall performance in terms of efficiency and pile up rejection Igor controls none C global none ControlTask to apply change 5 PAFLENGTH Removed TRIGGERDELAY Removed COINCDELAY This variable is used to delay individually for each channel the start of the coincidence window Since the coincidence test is applied only after validation each channel may require individual delay if validation requires different amounts of time due to differences in the energy filter settings For example a channel with the energy filter rise time set to 6 us would start the coincidence window 2 us before a channel with a filter rise time of 8 us and thus simultaneous events in the second channel will be lost unless the coincidence window is at least 2 us or the channel parameter COINCDELAY is set to 2 us for the faster channel The following formula should be used to determine COINCDELA Y COINCDELAY lt ch gt max PEAKSEP 2 FILTERRANGE cho ch3 PEAKSEP 2 FILTERRANGE Ja 57 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved User may choose different values based on the physics of the experiment The Igor control and the C global are in units of us the DSP variable i
21. requested parameter Return values Error ND ao Handling 0 Success None o OS Invalid system parameter index Check if Idx exceeds 63 Invalid module parameter index Check if Idx exceeds 63 Invalid channel parameter index Check if Idx exceeds 63 Invalid parameter type Check if SYSTEM MODULE or CHANNEL NULL parameter name array ptr Check ifUser Par Name is allocated 10 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved Usage example Check if parameter exists U8 ParName NULL U16 i 0 ParName malloc 80 sizeof char if ParName Not enough memory error handling while Pixie Get Par Name i MODULE ParName 1 if strcmp ParName FILTER RANGE printf FILTER RANGE exists Nn break EEE TEU S763 1 error handling 11 Pixie 4 Programmer s Manual V3 11 XIA 2014 All rights reserved Pixie Get Par Idx Syntax S16 Pixie Get Par Idx U8 User Par Name A string variable indicating the variable name being requested U8 User Par Type A string variable indicating which type of user parameters is being requested Description Use this function to identify parameter index by type SYSTEM MODULE CHANNEL in the type associated list The typical use of this function is to determine the index in User Par Values of Pixie User Par IO to transfer par
22. retval lt 0 Error handling read out the MCA spectrum and put it to array User data retval Pixie Acquire Data 0x9001 User data modnum if retval lt 0 Error handling Note that in clover addback mode the spectrum length is fixed to 16K for each channel plus 16K of addback spectrum Therefore the starting address of the MCA spectrum in the external memory for Channel 0 1 2 and 3 will be 0x00000000 0x000040000 0x00008000 0x00010000 respectively for the addback spectrum it is 0x00018000 34 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved 3 3 2 Access list mode data In the Pixie 4 and Pixie 500 there are two data buffers to choose from the DSP s local I O buffer 8K 16 bit words and a section of the external memory 128K 32 bit words Bit I in the variable MODCSRA selects which data buffer is filled during the run 19 Ifthe external memory is chosen to hold the output data the local buffer is transferred to the external memory when it has been filled Then the run resumes automatically without interference from the host until 32 local buffers have been transferred The data can then be read from external memory in a fast block read starting from location 0x00020000 19 Ifthe local buffer is chosen the run stops when the local buffer is filled The data has to be read out from local memory With any data buffer you can do any number of runs in a row The first run wo
23. runs Pixie 500 Express 0x301 MCA run Ox1 gt Ox7F control task runs handled by DSP 0x80 gt OxFF control task runs handled by C library Upper 4 bit 0x0000 start a control task run 0x0000 set offset DACs 0x0001 connect inputs Pixie 4 only 0x0002 disconnect inputs Pixie 4 only 0x0005 program Fippi FPGA 0x0006 measure baselines 0x0016 test writing to external list mode memory Should be called after most parameter changes applied directly to the DSP using Pixie Buffer IO Automatically called after parameter changes handled by the C library using Pixie User Par IO 14 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved 0x001A 0x0080 0x0081 0x0083 0x0084 0x1000 0x2000 0x3000 0x4000 0x5000 0x6000 0x7000 0x7001 0x7002 0x7003 0x7004 0x7005 0x7006 0x7007 0x7008 0x7010 0x8000 0x9000 0x9001 0x9002 0x9003 0x9004 test writing to external histogram memory measure baselines and compute BLcut for all modules find values of for all modules adjust offsets collect ADC traces start a new data run resume a data run stop a data run poll run status read histogram data and save it to a file read list mode buffer data and save it to a file offline list mode data parse routines parse list mode data file locate traces read traces read energies read PSA values read extended PSA values locate events read event custom parsing with user defined functions manually read MCA histogram from a MC
24. should be called to boot the modules The following code is an example showing how to boot the Pixie 4 modules using the API functions An Example Code Illustrating How to Boot Pixie 4 Modules 532 retval U8 d m c copy file names into Boot File Name List strcpy Boot File Name List 0 C Pixie4 firmware FippiP500 bin 0 29 Pixie 4 Programmer s Manual V3 11 XIA 2014 All rights reserved strcpy Boot File Name List 1 C Pixie4 firmware syspixie RevC bin 0 strcpy Boot File Name List 2 C Pixie4 firmware pixie bin 0 strcpy Boot File Name List 3 C Pixie4 dsp PXIcode bin 0 strcpy Boot File Name List 4 C Pixie4 configuration default set 0 strcpy Boot File Name List 5 C Pixie4 dsp PXIcode var 0 6 strcpy Boot File Name List etc for 7 12 7 C Pixie4 dsp PXIcode 1lst 0 initialize system parameter VALUES in C program Note indices have to be derived from NAME arrays table 3 5 System Parameter Values NUMBER MODULES Index 2 System Parameter Values OFFLINE ANALYSIS Index 0 System Parameter Values AUTO PROCESSLMDATA Index 0 System Parameter Values MAX NUMBER MODULES Index 7 System Parameter Values KEEP CW 1 System Parameter Values SLOT WAVE Index 110 System Parameter Values SLOT WAVE Index 1 111 do
25. tab C global XDT ControlTask to apply change none ENERGYLOW Removed LOG2EBIN This variable controls the binning of the histogram Energy values are always calculated to 16 bits precision The energy value corresponds to 4 times the 14 bit ADC amplitude The modules however do not have enough histogram memory available to record 64k spectra nor would this always be desirable The user is therefore free to choose a lower cutoff for the spectrum ENERGYLOW and control the binning by downshifting the computed energy The following formula describes which MCA bin a value of Energy will contribute MCAbin Energy 22LOG2bEBIN As can be seen Log2Ebin should be a negative number to achieve the correct behaviour At run start the DSP program ensures that Log2Ebin is indeed negative by replacing the stored value by abs Log2Ebin The C global BINFACTOR contains the absolute value of LOG2EBIN Constraints LOG2EBIN gt 65520 equiv 16 LOG2EBIN lt 65535 equiv 1 and additionally LOG2EBIN 0 is allowed 61 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved The histogramming routine of the DSP takes care of spectrum overflows and underflows Igor controls Binning Factor in the Advanced tab C global BINFACTOR ControlTask to apply change none CFDTHR This sets the threshold of the software constant fraction discriminator The threshold fraction CFD THRESHOLD f is encoded as round f 65536 with
26. would be those that depend on settings that may change in between runs UserChannel 75 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved This function is called for every event and every DGF 4C channel for which data are reported and for which bit 0 of the channel CSR B ChannelCSRB variable has been set It is called after all regular event processing for this channel has finished but before the energy has been histogrammed UserEvent This function is called after all event processing for this particular event has finished It may be used as an event finish routine or for purposes where the event as a whole is to be examined UserRunFinish This routine is called after the run has ended but before the host computer is notified of that fact Its purpose is to update run summary information Global variables UserIn 16 16 words of input data also visible to host UserOut 16 16 words of output data also visible to host Uglobals 32 32 words to pass global variables from the user code to the main code The use of these variables is controlled by the main code UretVal 6 User output data to be incorporated into list mode data The return value for UserChannel for list mode data is UretVal It is an array of 6 words If bit 1 of ChanCSRB is 0 only the first word is incorporated into the output data stream by the main code See Tables 4 2 to 4 6 in the user manual for the output data structure If the bit i
27. 0 lt f lt 1 Constraints CFDTHR gt 0 CFDTHR lt 65535 Igor controls CFD Threshold in the Waveform tab C global CFD THRESHOLD ControlTask to apply change none PSAOFFSET PSALENGTH When recording traces and requiring any pulse shape analysis by the DSP these two parameters govern the range over which the analysis will be applied The analysis begins at a point PSAOFFSET sampling clock ticks into the trace and is applied over a piece of the trace with a total length of PSALENGTH clock ticks PSAOFFSET PSA Start dt PSALENGTH PSA End PSA Start dt Constraints PSALENGTH gt 0 PSALENGTH lt TRACELENGTH PSAOFFSET PSAOFFSET gt 0 PSAOFFSET lt TRACELENGTH dt 13 3ns for Pixie 4 2ns for Pixie 500 and Pixie 500 Express Ignored for Pixie 500 Express Igor controls PSA Start PSA End in the Waveform tab C global PSA START PSA END ControlTask to apply change none INTEGRATOR This variable controls the energy reconstruction in the DSP INTEGRATOR 0 normal trapezoidal filtering INTEGRATOR 1 use gap sum only good for scintillator signals INTEGRATOR 2 ignore gap sum pulse height leading sum trailing sum good for step like pulses 62 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved For Pixie 4 and Pixie 500 INTEGRATOR 3 4 5 same as 1 but multiply energy by 2 4 or 8 Igor controls Integrator in the Energy tab C global INTEGRATOR ControlTask to apply change n
28. 2 is odd EM address block 1 128K EM address block 2 196K After readout the host must read the WordCount Register a second time to notify the DSP that the block just read is now freed up As an example see Write List Mode File in utilities c which is the only function in the Pixie 4 C library modified for the double buffer readout To stop runs it is recommended that the host keeps count of the number of spills and or time and issues a Stop Run command when a user defined number of spills and or acquisition time is reached There is no counting of time or spills in the DSP runs only stop when both EM blocks are filled or due to a host stop In the future the information in EMwords EMwords2 and DBLBUFCSR may be moved to CSR bits and the Word Count Register so that no reads writes to DSP memory are required during readout There will also be further modifications to reduce the transfer dead time 81 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved
29. 20 SGA amp 0x40 gt 0 53 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved The C library computes the closest SGA setting for a given voltage gain VGAIN and adjusts the parameter DIGGAIN to compensate differences between VGAIN and the gain from SGA up to 10 For the Pixie 500 and Pixie 500 Express only SGA bit zero is active and it changes the gain from 1 to 3 Constraints SGA 0 SGA lt 127 Igor controls Gain V V in the OsciL Loscors panel C global VGAIN ControlTask to apply change 0 DIGGAIN The digital gain factor for compensating the difference between the user desired voltage gain and the SGA gain This is computed by the C library and limited to 10 in the following way DG voltage gain SGA gain 1 0 DIGGAIN 65535 DG if DG gt 0 65536 65535 DG if DG 0 Constraints DIGGAIN gt 0 for positive DG DIGGAIN lt 6554 DIGGAIN gt 64K 6554 for negative DG DIGGAIN lt 64K Other values between 6554 and 64K 6554 are possible but may lead to binning errors or other undesirable effects Igor controls Gain V V in the OsciL Loscors panel C global VGAIN ControlTask to apply change none UNUSEDAO or UNUSEDA1 Reserved SLOWLENGTH The rise time of the energy filter also called peaking time depends on SLOWLENGTH Energy Filter Rise Time SLOWLENGTH 2 FILTERRANGE dt Constraints SLOWLENGTH gt 2 SLOWLENGTH SLOWGAP lt 127 dt 13 3ns for Pixie 4 8ns
30. 2014 All rights reserved be used in customized user interfaces or applications It can also be compiled for Linux and a sample ROOT interface is available from XIA In order to better illustrate the usage of these functions an overview of the Pixie operation is given below and the usage of these functions is described in the following At first the Pixie API needs to be initialized This is a process in which the names of system configuration files and variables are downloaded to the API The function Pixie Hand Down Names is used to achieve this The second step is to boot the Pixie modules It involves initializing each PXI e slot where a Pixie module is installed downloading all FPGA configurations and booting the digital signal processor DSP It concludes with downloading all DSP parameters the instrument settings and commanding the DSP to program the FPGAs and the on board digital to analog converters DACs All this has been encapsulated in a single function Pixie Boot System Now the instrument is ready for data acquisition The function used for this purpose is Pixie Acquire Data By setting different run types it can be used to start stop or poll a data acquisition run list mode run MCA run or special task runs like acquiring ADC traces It can also be used to retrieve list mode or histogram data from the Pixie modules After checking the quality of a MCA spectrum a Pixie user may decide to change one or more settings li
31. 3ns for Pixie 4 2ns for Pixie 500 2ns for the Pixie 500 Express 58 Pixie 4 Programmer s Manual V3 11 XIA 2014 All rights reserved TRACELENGTH must be a multiple of 4 for the Pixie 500 and a multiple of 32 for the Pixie 500 Express TLMAX 1024 for Pixie 4 8192 for Pixie 500 TLMAX min 4096 EFT for Pixie 500 Express where EFT is the energy filter time of the channel SLOWLENGTH SLOWGAP 2 FILTERRANGE Generally if TRACELENGTH gt TLMAX the size of the FIFO memory in the trigger filter FPGA the C library will force the TRACELENGTH to be equal to TLMAX In a debug test mode for Pixie 4 and Pixie 500 if direct download to the DSP sets a value greater than TLMAX the DSP will not read waveforms from FIFO memory but instead from the ADC register Since the DSP event readout occurs after the pileup inspection the waveform will in this case only contain data from after the pulse The time between samples is set by XWAIT Igor controls Trace Length in the Waveform tab C global TRACE LENGTH ControlTask to apply change 5 USERDELAY This variable specifies the number of pre trigger samples in the captured waveform USERDELAY Trace Delay dt Constraints USERDELAY 0 USERDELAY lt TRACELENGTH for Pixie 4 USERDELAY lt TRACELENGTH 32 for Pixie 500 USERDELAY lt 2047 for Pixie 500 dt 13 3ns for Pixie 4 2ns for Pixie 500 and Pixie 500 Express USERDELAY must be a multiple of 4 for the Pixie 500 and the Pi
32. 4 CHL contain the traces of channel 0 3 followed by some undefined values use tracelength to parse traces Summary of User data array in run task 0x7008 Location P4 Header P500e Header Value Pixie 500e or Pixie 4 Notes Location of event Location of event P500e unused Length of event TLO TLI TL2 TL3 BHO Unused or BUF NDATA BHI FHI Module number 9o oo 1 o0 tn Utt BH2 FH2 Run type data format indicator 0x100 0x403 BH3 CH6 TrigTimeHI or BUF_TIMEHI High 16 bits of Trigger or Buffer time 11 BH4 CH5 TrigTimeMI or BUF_TIMEMI Middle 16 bits of Trigger or Buffer time 12 BH5 CH4 TrigTimeLO or BUF TIMELO Lower 16 bits of Trigger or Buffer time 13 EHO CH1 0 EvtPattern and EvtInfo or EVT PATTERN 32 or 16 bit event info and hit pattern 14 EHI CH5 TrigTimeMI or EVT TIMEMI Middle 16 bits of Trigger or Event time 15 EH2 CH4 TrigTimeLO or EVT TIMELO Lower 16 bits of Trigger or Event time 16 CHO Unused or CHAN NDATA Channel data length 17 CHI CH5 4 TrigTimeMI and TrigTimeLO or CHAN TRIGTIME Lower 16 bits and middle 16 bits of Trigger time or all 16 bits of Channel time 17 Pixie 4 Programmer s Manual V3 11 XIA 2014 All rights reserved 18 CH2 CH8 CHAN_ENERG
33. 6 bit in COINCPATTERN cover all combinations Setting COINCPATTERN to OxFFFF causes the Pixie 4 to accept any hit pattern as valid Igor controls Checkboxes in the Coincidence tab C global COINCIDENCE PATTERN ControlTask to apply change 5 COINCWAIT Duration of the coincidence time window in clock cycles 13 3 ns for Pixie 4 or Pixie 500 8ns for Pixie 500 Express This parameter is used to define a time window from the first event validation until the final hit pattern is latched for the coincidence test This accommodates delays between channels due to cabling or the physics of the experiment Since the coincidence test is applied only after validation each channel may require individual delay if validation requires different amounts of time due to differences in the energy filter settings For example a channel with the energy filter rise time set to 6 us would start the coincidence window 2 ys before a channel with a filter rise time of 8 us and thus simultaneous events in the second channel will be lost unless the coincidence window is at least 2 us or the channel parameter COINCDELAY is set to 2 us for the faster channel The following formula should be used to determine COINCDELA Y COINCDELAY lt ch gt max PEAKSEP 2 FILTERRANGE cho chs PEAKSEP 2 FILTERRANGE Ja Only channels marked as good in the CHANCSRA need to be included in this computation The maximum pileup inspection time is reported back to the user for r
34. A file external memory EM I O read histogram memory section of EM write to histogram memory section of EM read list mode memory section of EM write to list mode memory section of EM User data has the following format for the run types listed below 0x84 Get ADC traces Length must be ADCTraceLen NumberOfChannels 1 e 8192 4 32K All array elements are return values the Nth 8K of data are the ADC trace of channel N 0x7001 Parse list mode data file Length must be 2 PRESET MAX MODULES i e 34 All array elements are return values User data 1 NumEvents of module i User dataliiPRESET MAX MODULES TotalTraces of module 1 0x7002 Locate Traces of all events Length must be TotalTraces of ModNum 3 NumberOfChannels Combined action of DSP and C library DSP will perform the controltask 3 or 4 described in section 4 5 and C library will use the results For backwards compatibility RunType 0x0003 or 0x0004 are translated into 0x0083 or 0x0084 respectively in the C library 15 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved All array elements are return values User data i 3n 7 Location of channel n s trace in file for event i word number User datali 3n 1 length of channel n s trace User data i 3n 2 energy for channel n 0x7003 Read Traces of one event Length must be NumberOfChannels 2 combined tracelength of channels First NumberOfChannels 2 elements are input values
35. AX MODULES i sum the total number of traces for all modules totaltraces List Data it PRESET MAX MODULES allocate memory to hold the starting address trace length and energy of each trace therefore 3 32 bit words are needed for each trace traceposlen U32 malloc totaltraces 3 NUMBER OF CHANNELS if traceposlen NULL if retval lt 0 Error handling locate traces in the data file retval Pixie Acquire Data 0x7002 traceposlen DataFile modnum if retval lt 0 Error handling allocate memory to hold the first trace 2 extra 16 bit words for notifying the API the trace position and length information Trace0 U16 malloc traceposlen 1 2 if retval lt 0 Error handling Trace0 0 traceposlen 0 position of the first trace 38 Pixie 4 Programmer s Manual V3 11 XIA 2014 All rights reserved Trace0 1 traceposlen 1 length of the first trace read out the first trace and put it into trace0 retval Pixie Acquire Data 0x7003 Trace0 DataFile modnum if retval 0 Error handling 39 Pixie 4 Programmer s Manual V3 11 XIA 2014 All rights reserved 4 User Accessible DSP Variables User parameters are stored in the data memory space of the on board DSP The organization is that of a linear memory with 16 bit words Subsequent memory locations are indicated by increasing a
36. C step and uses the last computed DC offset value to enter into the data buffer Due to electronic noise it may occasionally happen that none of the sixteen attempts at a base line measurement is successful in which case a zero is returned The user software must be able to cope with an 70 Pixie 4 Programmer s Manual V3 11 XIA 2014 All rights reserved ControlTask 4 ControlTask 5 ControlTask 6 occasional deviation from the expected straight line On exit the task restores the offset DAC values to the values they had on entry When called through the C library using Pixie Acquire Data 0x0083 the C library will call this task for each cannel and module and then use the ram data to adjust the offsets to the target value specified by the variable BASELINEPERCENT Untriggered Traces This task provides ADC values measured on all four channels and gives the user an idea of what the noise and the DC levels in the system are This function samples 8192 ADC words for the channel specified in CHANNUM The XWAIT variable determines the time between successive ADC samples In the Pixie Viewer XWAIT can be adjusted through the dT variable in the Oscilloscope panel The results are written to the 8192 words long I O buffer Use this function to check if the offset adjustment was successful When called through the C library using Pixie Acquire Data 0x0084 the C library will call this task for each cannel of the selected mo
37. KSEP 2 FILTERRANGE after the rising edge of a pulse Polarity can be reversed in CHANCSRC Histogram energies Set this bit to histogram energies from this channel in the on board MCA memory Reserved Set to 0 If set allow negative number as the result of the pulse height computation This may be useful in list mode runs to return a rough measure of an inverted pulse Due to the binary representation of negative numbers the pulse height will be histogrammed into bin 64K abs pulse height of the spectrum This option is ignored in MCA runs 50 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved Bit 10 Bit 11 Bit 12 Bit 13 Bit 14 Bit 15 Compute constant fraction timing This pulse shape analysis computes the time of arrival for the signal from the recorded waveform The result is stated in units of 1 256 of a sampling period 13 3 ns Time zero is the start of the waveform Ignored for Pixie 500 Express Reserved Enabled multiplicity contribution in DGF 4C GATE required Pixie 4 only Set this bit if you want to validate or veto events based on a individual signal GATE is distributed over a PXI left neighbor line for example from a PDM in the slot to the left of the Pixie 4 Each channel has its own line When the bit is set the event is accepted only if validated by GATE To be validated the GATE input must have a rising edge within a time window defined by GATEWINDOW and GATEDELA
38. OF CHANNELS I currently NUMBER OF CHANNELS is set to 4 Return values Error Handling 0 Success None Invalid module number Check Module Invalid channel number Check Channel Usage example Set current module to 1 and current channel to 3 Pixie Set Current ModChan 1 3 22 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved Pixie Buffer IO Syntax 532 Pixie Buffer IO U16 Values An unsigned 16 bit integer array containing the data to be transferred U8 type Data transfer type U8 direction Data transfer direction U8 file name File name U8 ModNum Module number Description Use this function to 1 Download or upload DSP parameters between the user interface and the Pixie modules 2 Save DSP parameters into a settings file or load DSP parameters from a settings file and applies to all modules present in the system 3 Copy parameters from one module to others or extracts parameters from a settings file and applies to the selected modules Parameter description Values is an unsigned 16 bit integer array used for data transfer between the user interface and Pixie modules type specifies the I O type direction indicates the data flow direction The string variable file name contains the name of settings files Different combinations of the three parameters Values type direction designate different I O operations as listed in Table 2 2
39. On the other hand if users want to read out the data memory the API will first convert these DSP values into the global variable values Tables 3 5a c give a complete description of all the global variables being used by the Pixie API The code shown below is an example of setting DSP variables through the API An Example Code Illustrating How to Set DSP Variables through the API 532 retval U8 direction modnum channum direction 0 download modnum 0 Module 0 channum 0 Channel 0 Note xxx Index has to be derived from NAME array table 3 5 set COINCIDENCE PATTERN to OxFFFF Module Parameter Values COINCIDENCE PATTERN Index OxFFFF download COINCIDENCE PATTERN to the DSP retval Pixie User Par IO Module Parameter Values COINCIDENCE PATTERN MODULE direction modnum channum if retval lt 0 Error handling set ENERGY RISETIME to 6 0 us Channel Parameter Values ENERGY RISETIME Index 6 0 download ENERGY RISETIME to the DSP retval Pixie User Par IO Channel Parameter Values ENERGY RISETIME CHANNEL direction modnum channum if retval 0 Error handling 31 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved Table 3 5a Descriptions of System Global Variables in Pixie 4
40. P code memory variable names file All file names should contain the complete path name 2 SYSTEM This indicates we are downloading System Parameter Names System Parameter Names are those global variables that are applicable to all modules in a Pixie system e g number of Pixie modules in the chassis etc System Parameter Names currently can hold 64 names If less than 64 names are needed which is the current case the remaining names should be defined as empty strings 3 MODULE This indicates we are downloading Module Parameter Names Module Parameter Names are those global variables that are applicable to each individual module e g module number module CSR coincidence pattern and run type etc Module Parameter Names can currently hold 64 names If less than 64 names are 3 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved needed which is the current case the remaining names should be defined as empty strings 4 CHANNEL This indicates we are downloading Channel Parameter Names Channel Parameter Names are those global variables that are applicable to individual channels of the Pixie modules e g channel CSR filter rise time filter flat top voltage gain and DC offset etc Channel Parameter Names currently can hold 64 names If less than 64 names are needed which is the current case the remaining names should be defined as empty strings A detailed description of System Module Channel Parameter Na
41. Programmer s Manual Digital Gamma Finder DGF Pixie 4 Pixie 500 Pixie 500 Express Version 3 11 June 2014 XIA LLC 31057 Genstar Road Hayward CA 94544 USA Phone 510 401 5760 Fax 510 401 5761 http www xia com Disclaimer Information furnished by XIA is believed to be accurate and reliable However XIA assumes no responsibility for its use or for any infringement of patents or other rights of third parties which may result from its use No license is granted by implication or otherwise under the patent rights of XIA XIA reserves the right to change the DGF product its documentation and the supporting software without prior notice Table of Contents Eve REN ER ER i SE RR e ol paie NR 1 Fe NN NE a pees 3 NNN Ad 5 Pee Uer Pir innar 7 Pode Get OR 10 Pie et Por PR REN ERR ELE EE 12 laki Reis p Doi e 14 EE ER p pL ip Bao aaa di dara 22 Paie Tuer Me 23 Optone tor Corp Pirie API ERE 26 3 Control Pixie Modules via C POTTS eas baskere nininini 28 JE IC A ONE 28 JET LE ke decide kid ed ord Lista a Malin d adus ko alc o oi 28 3 1 2 Boot Pixie Modules Rem 29 EL GLA RR EE 31 3 3 Access spectrum memory or list mode data smresesvrnressnnrnsnsesennnasssvrnnasssvrnannnnsnnsasoknsen 34 REE Je RR 34 ERFARE ENE 35 Her Acvessible DSP Vad udi ab sa 40 4 1 Module input PAST ks scenic i psit cpi d arr vade eee rk in prb 40 Eee kr GJEN 49 4 3 Module GL Ge ER 65 EG KELTERE PE age et ccdpaieeu
42. TRIGGER THRESHOLD causes triggering at the same pulse amplitude independent of FASTLENGTH FASTTHRESH TRIGGER THRESHOLD FASTLENGTH If FASTTHRESH 0 the trigger logic is switched off The trigger enable bit in ChanCSRA only disables triggers being sent to the DSP for event processing and to other channels modules for synchronous waveform capture FASTTHRESH 0 switches off local trigger generation so e g the input count rate becomes zero Constraints FASTTHRESH gt 0 FASTTHRESH lt 4095 the lower 3 bits are ignored Igor controls Threshold Rise Time in the Trigger tab C global TRIGGER THRESHOLD TRIGGER RISETIME ControlTask to apply change 5 MINWIDTH Unused 56 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved MAXWIDTH This value aids the pile up inspection MAXWIDTH is the maximum duration in sample clock ticks 13 3 ns which the output from the fast filter may spend over threshold Pulses longer than that will be rejected as piled up The recommended setting is zero to disable this feature Otherwise a possible starting value is MAXWIDTH FASTLENGTH FASTGAP SignalRiseTime dt Constraints MAXWIDTH gt 0 MAXWIDTH lt 255 dt 13 3ns for Pixie 4 8ns for Pixie 500 and Pixie 500 Express Once the other parameters have been optimized with MAXWIDTH 0 one can use the MAXWIDTH cut to improve the pile up rejection at high count rates MAXWIDTH should be tuned by observing the
43. Table 2 2 Different I O operations using function Pixie Buffer IO Direction Values I O Operation DSP I O variabl Write DSP I O variable values to modules variable values Read DSP I O variable values from modules 0 Values to be written Write to certain locations of the data memor 1 1 All DSP variable values Read all DSP variable values from modules Save current settings in all modules to a file 1 1 N A Read settings from a file and apply to all modules in the system Values 0 source module Extract settings from a file and apply to number Values 1 source selected modules channel number Values 2 copy extract pattern bit mask Copy settings from a source module to Values 3 Values 4 destination modules destination channel pattern 23 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved Values 0 address Values 1 Specify the location and number of words to be 4 N A length written into the data memor Notes Special care should be taken for this I O operation since mistakenly writing to some locations of the data memory will cause the system to crash The Type 4 I O operation should be called first to specify the location and the number of words to be written before calling this one If necessary please contact XIA for assistance Any unsigned 16 bit integer array could be used here Direction can be either 0 or 1 and it has no effect on the operation Re
44. When Igor is set to store output data in new files every N spills or seconds this function is called at the end of making the new files before the run has resumed It can be used to e g change acquisition parameters or save the Igor experiment during these multi file runs However it will interfere with the polling routine so the time to execute User NewFileDuringRun should be less than the polling time 77 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved Function User StopRun This function is called at the end of the run By default it calls another function to duplicate the output data displayed in the standard Igor graphs and panels into a data folder called root results It can be used to process output data Function User ChangeChannelModule This function is called when changing Module Number or Channel Number By default it calls a function to update the variables in the User Control panel Function User ReadEvent This function is called when changing event number in list mode trace display or digital filter display By default it duplicates traces and list mode data into the results data folder Function User TraceDataFile This function is called when changing the file name in list mode trace display Function User HomePaths This function is called when executing the UseHomePaths macro It can be used to specify custom file names 6 2 Igor User Panels The Igor user panels define
45. Y around the rising edge of a detector pulse When the bit is cleared the GATE input is not used for event validation but its status is reported in the list mode output data Polarities of the edge starting the Window and the status required for accepting events can be selected in CHANCSRC Local trigger timestamp If set use the local trigger to latch the time stamp even in group trigger mode else use the distributed group trigger Ignored for Pixie 500 Express Estimate energy if channel not hit If set the DSP reads out energy filter values and computes the pulse height for a channel that is not hit for example when read always in group trigger mode If not set the energy will be reported as zero if the channel is not hit For Pixie 500 Express pulse heights computed in group trigger mode are always based on the distributed not local trigger Reserved Igor controls Checkboxes in the PARAMETER SETUP panel C global CHANNEL CSRA ControlTask to apply change 5 CHANCSRB Control and status register B for user code Bit 0 Bit 1 Bit2 15 If set call user written DSP code If set all words in the channel header except Ndata TrigTime and Energy will be overwritten with the contents of URETVAL Depending on the run type this allows for 6 2 or 0 user return values in the channel header reserved Set to 0 Bits 2 and 3 are used in MPI custom code Igor controls Variables in the USER CONTROL panel C g
46. Y energy 19 CH3 CH11 CHAN XIAPSA XIA PSA value or user return 20 CH4 CH10 CHAN USERPSA USER PSA value or user return 21 CH5 CH12 Unused user return 22 CH6 CH13 Unused user return 23 CH7 CH14 Unused user return 24 CH8 CH15 Unused or TIME HI user return or High 16 bits of time Channel header repeated 4 times Followed by waveforms 0x8000 Read MCA data from file one module Length must be HISTOGRAM MEMORY LENGTH 131072 0x9001 Read MCA data from one module Length must be HISTOGRAM MEMORY LENGTH 131072 0x9002 Write MCA data to one module debug Length must be HISTOGRAM MEMORY LENGTH 131072 0x9003 Read List mode data in external memory from one module Length must be LIST MEMORY LENGTH 131072 0x9004 Write List mode data to external memory one module debug Length must be LIST MEMORY LENGTH 131072 file name is a string variable which specifies the name of the output file It needs to have the complete file path ModNum is the number of the module addressed counting from 0 to number of modules 1 If ModNum number of modules all modules are addressed in a for loop however this option is not valid for all RunTypes Return values Return values depend on the run type Run type 0x0000 None 0x1 Check ModNum 0x2 Reboot the module 0x3 Failure to acquire ADC traces Reboot the module 0x4 Failure to start the control task run Reboot the modu
47. alue to the DSP variables then report success or failure The function Pixie4 User Par IO should then be called with argument ALL CHANNEL PARAMETERS to update user interface parameters from the DSP variables ControlTask 131 Adjust offset for all modules This routine is used to adjust DC offsets to the target value BASELINEPERCENT for all channels and modules The C library will call ControlTask 3 in the DSP for each channel and module compute the offset and set the offset DACS to the appropriate value ControlTask 132 Read untriggered ADC traces This routine is used to read untriggered ADC traces for all channels or a module The C library will call ControlTask 4 in the DSP for each channel and return the result in the User data block ControlTask 2132 reserved for tasks performed by C library not DSP 73 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved 5 Appendix A User supplied DSP code 5 1 Introduction It is possible for users to enhance the capabilities of the Pixie 4 by adding their own DSP code XIA provides an interface on the DSP level and has built support for this into the Pixie 4 Viewer The following sections describe the interfaces and support features 5 2 The development environment For the DSP code development XIA uses and recommends version 5 or 6 of the assembler and linker distributed by Analog Devices Both versions are in use at XIA and work fine It may be inconvenient but is un
48. ameter values to and from the device Parameter description User Par Type is a string describing the type of the parameter in consideration SYSTEM MODULE or CHANNEL User Par Name is the name of the variable for which the index is being requested Return values Error Handling Handling i GENER ERE None 2s ro Invalid parameter type Check if SYSTEM MODULE or CHANNEL Invalid system parameter name Check spelling Invalid module parameter name Check spelling Invalid channel parameter name Check spelling 12 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved Usage example Write to module SysParVal SysParVal SysParVal SysParVal SysParVal Pixie User Par Pixie User Par Pixie User Par Pixie User Pa Pixie User Par Pixie Ge Pixie Ge Pixie Ge Pixie Ge ct ct ct ct c U U U o 9 U w l l U o R MO ry DU ANA ES YSIS F PROCESS gu Ti F B R MODULI MDATA SYSTEM SYSTEM SYST fi 1 r 0 a MODU ANA ES YSIS 13 PROCESS B AU MDATA SYST ER MODULES SYST EO VEKST SYST SYSTEM SYSTEM T 1 MOD WRITE MOD WRITE MOD WRITE MOD WRITE MOD WRITE r rz F a y a
49. ange Constraints BASELINEPERCENT gt 0 BASELINEPERCENT lt 100 Igor controls Offset in the OSCILLOSCOPE C global BASELINE PERCENT ControlTask to apply change none UNUSEDBO or UNUSEDBI Reserved CFDREG Removed 63 Pixie 4 Programmer s Manual V3 11 XIA 2014 All rights reserved LOG2BWEIGHT The Pixie 4 module measures baselines continuously and effectively extracts DC offsets from these measurements The DC offset value is needed to apply a correction to the computed energies To reduce the noise contribution from this correction baseline samples are averaged in a geometric weight scheme The averaging depends on LOG2BWEIGHT DC avg DC avgoaa DC DC avgua 22LOG2BWEIGHT DC is the latest measurement and DC avg is the average that is continuously being updated At the beginning and at the resuming of a run DC avg is seeded with the first available DC measurement The DSP ensures that LOG2BWEIGHT will be negative Larger absolute numbers mean the previous baseline measurements contribute more The noise contribution from the DC offset correction falls with increased averaging The standard deviation of DC avg falls in proportion to sqrt 22LOG2BWEIGHT When using a BLCUT value from a noise measurement cf control task 6 the Pixie 4 will internally adjust the effective Log2Bweight for best energy resolution up to the maximum value given by LOG2BWEIGHT Hence the LOG2BWEIGHT setting should be chos
50. annel parameter ENERGY RISETIME to 6 0 us Channel Parameter Values ENERGY RISETIME Index 6 0 download ENERGY RISETIME to DSP retval Pixie User Par IO Channel Parameter Values ENERGY RISETIME CHANNEL direction modnum channum if retval 0 error handling 9 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved Pixie Get Par Name Syntax 532 Pixie Get Par Name U16 Idx Parameter index in the array of parameter names U8 User Par Type A string variable indicating which type of user parameters is being requested U8 User Par Name The pointer to a string array to contain the variable name being requested Description Use this function to identify user parameters by type SYSTEM MODULE CHANNEL and index in the type associated list The typical use of this function is to check whether a particular variable exists in the list or to create a local copy of the entire list Parameter description Idxis an unsigned short variable indicating the sequential number of a user controlled parameter in the list of SYSTEM MODULE or CHANNEL type parameters User Par Type is a string describing the type of the parameter in consideration SYSTEM MODULE or CHANNEL User Par Name is a character array of at least size 80 to contain the name of the
51. ar Values A double precision array containing the user parameters to be transferred U8 User Par Name A string variable indicating which user parameter is being transferred U8 User Par Type A string variable indicating which type of user parameters is being transferred U16 Direction I O direction read or write U8 ModNum Number of the module to work on U8 ChaNum Channel number of the Pixie module Description Use this function to transfer user parameters between the user interface the API and DSP s I O memory Some of these parameters User Par Type SYSTEM are applicable to all Pixie modules in the system like the total number of Pixie modules in the system Other parameters User Par Type MODULE are applicable to a whole Pixie module independent of its four channels e g coincidence pattern Module CSRA etc The final set of parameters User Par Type CHANNEL are applicable to each individual channel in a Pixie module e g energy filter settings or voltage gain etc For those parameters which need to be transferred to or from DSP s internal memory other parameters such as number of modules are only used by the API this function will call another function UA PAR IO which first converts these parameters into numbers that are recognized by both the DSP and the API then performs the transfer Parameter description User Par Values is a double precision array containing th
52. atcal 68 ii Pixie 4 Programmer s Manual V3 10 XIA 2014 All rights reserved 1 Overview This manual is divided into three major sections The first section is a description of the Pixie application program interface API Advanced users can build their own user interface using these API functions The second section is a reference guide to program the Pixie modules using the Pixie 4 API This will be interesting to those users who want to integrate the Pixie modules into their own data acquisition system The third section describes the variables controlling the functions of the Pixie modules Advanced and curious users can use this section to better understand the operation of the Pixie modules Additionally this manual includes instructions on how to integrate custom user code into the digital signal processor DSP and Igor The API and most of the variables are identical for the Pixie 4 the Pixie 500 and the Pixie 500 Express Most of the text will mention Pixie modules and stand for all of the 3 devices For variables specific to a particular model the use and value are described explicitly and the text is highlighted Changes in Version 3 00 In version 3 00 WinDriver libraries and corresponding functions have been added to support the PCI Express I O for the Pixie 500 Express modules While many functions and features are identical and top level API functions are almost unchanged the following differences exist e P
53. avoidable to program the ADSP 2185 on board processor in assembler rather than in a higher level programming language like C We found that code generated by the C compiler is bloated and consequently runs very slow As the main piece of the code could not be written in C at all we did not burden our design by trying to be compatible with the C compiler Hence using the C compiler is currently not an option With the general software distribution we provide working executables and support files To support user DSP programming we provide files containing pre assembled forms of XIA s DSP code together with a source code file that has templates for the user functions The user templates have to be converted by the assembler and the whole project is brought together by the linker XIA provides a link and a make file to assist the process In the Pixie 4 Viewer we provide diagnostic tools to aid code developing and a data interface to exchange data between the host and the user code The Pixie 4 Viewer can at any time examine the complete memory content of the DSP and call any variable from any code section by name A particularly useful added feature is the capability to download data in native format into the DSP and pretend that they were just acquired The event processing routine which calls the user code is then activated and processes the data This in situ code testing allows the most control in the debugging process and is more powerful than ha
54. ays is in units of 2 2 5 ns Ignored for Pixie 500 Express timestamps are always in units of 2 ns 41 Pixie 4 Programmer s Manual V3 11 XIA 2014 All rights reserved Bit 11 Bit 12 Bit 13 Bit 14 Bit 15 reserved If set the module will drive low the TOKEN backplane line used to distribute the result of the global coincidence test 1f its local coincidence test fails This way a module can inhibit all other module from acquiring data according to its local coincidence test Ignored for Pixie 500 Express If set the module will send out its hit pattern to slot 2 using the PXI STAR trigger line for each event This option must not be enabled in slot 2 because slot 2 can not send signals to itself The line is instead used for chassis clock distribution and therefore should be left alone Ignored for Pixie 500 Express If set the front panel input DSP out is connected as an input to the Status line on the backplane The Status line is set up as a wire OR so more than one module can enable this option Ignored for Pixie 500 Express Controls sharing of triggers over backplane See bit 2 Igor controls checkboxes mostly in the CHASSIS SETUP panel C global MODULE CSRA The C library checks for the dependencies listed above ControlTask to apply change 5 MODCSRB The Module Control and Status Register B Bit 0 Execute user code routines programmed in user dsp Bits 1 15 Reserved for user
55. be correlated across channels At the end of a run the closing routine may call UserRunFinish typically for updating statistics and similar run end tasks The above mentioned routines are described below including the interface variables and the permissible use of resources 5 4 The interface The interface consists of five routines and a number of global variables Data exchange with the host computer is achieved via two data arrays that are part of the I O parameter blocks visible to the host The total amount of memory available to the user comprises 2048 instructions and 1100 data words Interface DSP routines UserBegin This routine is called after rebooting the DSP Its purpose is to establish values for variables that need to be known before the first run may start Address pointers to data buffers established by the user are an example The host will need know where to write essential data to before starting a run Since the DSP program comes up in a default state after rebooting UserBegin will always be called This is different for the routines listed below which will only be called if for at least one channel bit 0 of ChannelCSRB has been set UserRunlnit This function is called at each run start for new runs as well as for resumed runs The purpose is to precompute often needed variables and pointers here and make them available to the routines that are being called on an event by event basis The variables in question
56. cessing FPGA includes 1 2 3 4 5 and 6 Igor controls Filter Range in the Energy tab C global FILTER RANGE C library computes dependencies ControlTask to apply change 5 MODULEPATTERN To determine if an event is acceptable according to local or global coincidence tests the DSP computes the quantity MODULEPATTERN AND HITPATTERN AND OxOFFF If nonzero the event is accepted HITPATTERN bits 4 7 contain the following status information 4 Logic level of FRONT panel input 5 Result of LOCAL coincidence test 6 Logic level of backplane STATUS line 7 Result of GLOBAL coincidence test TOKEN backplane line Logic levels are captured at the time the coincidence window closes Consequently to accept events based only on the local coincidence test bit 5 of MODULEPATTERN must be 1 and all others zero To accept events based only on the global coincidence test bit 7 of MODULEPATTERN must be 1 and all others zero To accept events based on both tests either test passed accept set bits 5 and 7 of MODULEPATTERN to one others to zero Other values of MODULEPATTERN can in principle be used but are not tested and or supported at this time Igor controls Checkboxes in the CHASSIS SETUP panel C global MODULEPATTERN ControlTask to apply change none NNSHAREPATTERN 16 bit user defined control word for PXI PDM If enabled MODCSRA the Pixie 4 module writes this word to its left neighbor using a PXI left neighbor line which
57. code Igor controls variable in the USER CONTROL panel C global MODULE CSRB ControlTask to apply change none MODCSRC The Module Control and Status Register C Bits 0 15 Reserved Igor controls none C global MODULE CSRC ControlTask to apply change none MODFORMAT Removed RUNTASK This variable tells the Pixie 4 what kind of run to start in response to a run start request Six run tasks are currently supported 42 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved RunTask Mode Trace CHANHEADLEN Capture 256 0x100 Standard list mode P4 500 Yes 9 257 0x101 Compressed list mode Yes 19 258 0x102 Compressed list mode 259 0x103 769 0x301 1024 0x400 RunTask 0 is used to request slow control tasks These include programming the trigger filter FPGAs setting the DACs in the system transfers to from the external memory and calibration tasks RunTask 256 0x100 requests a standard list mode run for Pixie 4 or Pixie 500 In this run type all bells and whistles are available The scope of event processing includes computing energies to 16 bit accuracy and performing pulse shape analyses for improved energy resolution and better time of arrival measurements Nine words of results including time of arrival energy XIA pulse shape analysis user pulse shape analysis etc are written into the I O buffer for each channel Level 1 buffer is not used in this RunTask R
58. d there is a channel header containing energy and auxiliary information CHANHEADLEN is the length of this header CHANHEADLEN varies between 2 and 32 words depending on the run type see RUNTASK For Pixie 4 and Pixie 500 in runtasks 0x10 the event and channel header lengths plus the requested trace lengths determine the maximum logically possible event size The maximum event size is the sum of EVENTHEADLEN and the CHANHEADLENs plus the TraceLengths for all channels marked as good i e which have bit 2 in the CHANCSRA set Example With all four channels marked as good and required trace lengths of 1000 i e 13 3 s the maximum event size will be 66 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved MaxEventSize EVENTHEADLEN 4 CHANHEADLEN 1000 4039 In the last line typical values for EVENTHEADLEN 3 and CHANHEADLEN 9 were substituted BUFHEADLEN equals 6 Thus there is room for at least 2 events in the list mode data buffer which is 8192 words long But there is only room for I event in the level 1 buffer used in compressed RUNTASKs 0x101 103 which contains only 4060 words EMWORDS EMWORDS2 Each of these variables are two word arrays high word first counting the number of 16 bit words written to external memory Pixie 4 and Pixie 500 only USEROUT 16 words of user output data which may be used by user written DSP code AOUTBUFFER Address of the IO data buffer The addresses are generated
59. d in the current version of the user code are listed below Window User Control this is the main user control panel listing DSP input and output variables and showing several action buttons This panel can be modified to set user variables and control user procedures Window User Version ctrIName This panels displays the version and variants of the user code UserVersion the version of the user function calls defined by XIA UserVariant the variant of the code written by the user USEROUT 0 the version of the DSP code written by the user 78 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved 6 3 Igor User Variables The main Igor code defines the global variables and waves below for use in user procedures The user code can modify these values without interfering with the main code An exception is the User Version which should not be modified but used to ensure the user code is compatible with the main code NewDataFolder o root results the Igor data folder where results for user are stored Variable G root results RunTime Run Time from run statistics panel Variable G root results EventRate Event rate from run statistics panel Variable G root results NumEvents Total number of events Wave root results ChannelLiveTime Channel live time 0 3 Wave root results ChannelInputCountRate Channel input count rate 0 3 String G root results StartTime Start time from run statistics panel St
60. ddresses The data memory space as seen by the host computer starts at 0x4000 in the Pixie 4 and Pixie 500 and at 0 in the Pixie 500 Express There are two sets of user accessible parameters 256 words in data memory are used to store input parameters These can and must be set properly by the user application A second set of 256 words is used for results furnished by the Pixie module These should not be overwritten As of this writing the two blocks are contiguous in memory space We provide an ASCII file named PXIcode var or P500code var or P500e var which contains in a 2 column format the offset and name of every user accessible variable We suggest that user code use this information to create a name address lookup table rather than relying on the parameters retaining their address offsets with respect to the start address The input parameter block is partitioned into 5 subunits The first contains 64 words that pertain to the Pixie 4 as a whole It is followed by four blocks of 48 words which describe the settings of the four channels Below we describe the module and channel parameters in turn Also listed are the corresponding C global variable names and the corresponding control in Igor where the user can set the value of the variable Unless it is a simple 1 1 copy we also show the conversion process from the Igor variable or C global variable to the DSP parameter 4 1 Module input parameters MODNUM Logical number of the modu
61. dule and return four 8K traces in the User data block From the Pixie 4 Viewer this function is available through the Oscilloscope Panel by clicking on the Refresh button ProgramFiPPI This task writes all relevant data to the FiPPI control registers Measure Baselines This routine is used to collect baseline values Currently DSP collects six words BOL BOH BIL B1H time stamp and ADC value for each baseline 1365 baselines are collected until the 8192 word I O buffer is almost completely filled The host computer can then read the I O buffer and calculate the baseline according to the formula Baseline B1 B0 exp XP Bnorm with Bl BIL BIH 65536 BO BOL B0H 65536 XP SLOWLENGTH SLOWQGAP 2FLTERRANGE 75 TAU Bnorm 2 SLOWLENGTH for FILTERRANGE gt 2 2 SLOWLENGTH for FILTERRANGE 1 71 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved 27 SLOWLENGTH for FILTERRANGE 0 TAU PREAMPTAUA PREAMPTAUB 65536 Baseline values can then be statistically analyzed to determine the standard deviation associated with the averaged baseline value and to set the BLCUT BLCUT should be about 4 times the standard deviation Baseline values can also be plotted against time stamp or ADC value to explore the detector performance BLCUT should be set to zero while running ControlTask 6 ControlTask 22 Test EM write Pixie 4 and Pixie 500 only This routine is used to write a test pattern fr
62. e except RUN TYPE MODULE RUN STATISTICS read only read all module run statistics parameters of a module ALL CHANNEL PARAMETERS read only read all channel parameters of a channel of the 4 channel in a module Note The key words UPDATE FILTERRANGE PARAMS and FIND TAU are obsolete The former action is performed automatically after changing FILTERRANGE The latter is now a control task direction indicates the transfer direction of parameters 0 download write parameters from the user interface to the API I upload read parameters from the API to the user interface ModNum is the number of the Pixie module being communicated to ChanNum is the channel number of the Pixie module being communicated to Return values 0 Success Nome 1 z6 Invalid Pixie channel number Check ChanNum 8 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved Usage example U16 direction modnum channum S32 retval direction 0 download modnum 0 Module 0 channum 1 Channel 1 set module parameter COINCIDENCE PATTERN to OxFFFF Module Parameter Values Coincidence Pattern Index 0xFFFF download COINCIDENCE PATTERN to the DSP retval Pixie User Par IO Module Parameter Values COINCIDENCE PATTERN MODULE direction modnum channum if retval 0 error handling set ch
63. e parameters to be transferred Depending on another input parameter User Par Type different User Par Values array should be used Totally three User Par Values arrays should be defined and all of them are one dimensional arrays The corresponding relationship between User Par Values and User Par Type is shown in Table 2 1 Table 2 1 The Combination of User Par Name and User Par Values User Par Type User Par Values ie SYSTEM System Parameter Values MODULE Module Parameter Values 64317 Double precision CHANNEL Channel Parameter Values 6421724 Double precision The way to fill the Channel Parameter Values array is to fill the channel first then the module For instance first 64 values are stored in the array for channel 0 and then repeat this for other 7 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved three channels After that 6434 values have been filled for module 0 Then repeat this for the remaining modules For the Module Parameter Values array first store 64 values for module 0 and then repeat this for the other modules User Par Name is the name of the variable which is to be transferred It is one element of one of the arrays System Module Channel Parameter Names listed in Table 3 5 In addition the following keywords are recognized Key Word Action ALL SYSTEM PARAMETERS read only read all system parameters ALL MODULE PARAMETERS read only read all module parameters of a modul
64. eference in the variable MIN COINCIDENCE WAIT in clock cycles When energy filter rise time or flat top or CHANCSRA are changed from Igor the C library computes if channels need to be delayed to compensate for energy filter differences The application of the delay depends on the System global KEEP CW If KEEP CW is 0 COINCDELA YO 3 are set to the user specified time No compensation is applied 45 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved If KEEP CW is 1 COINCDELAYO 3 are set to the required compensation time Any user input is ignored The Igor control and the C global are in units of us the DSP variable is in units of clock cycles 13 3ns for both Pixie 4 and Pixie 500 8ns for Pixie 500 Express Constraints COINCWAIT gt I COINCWAIT lt 65531 for Pixie 4 and Pixie 500 COINCWAIT lt min 127 minEFT for Pixie 500 Express minEFT is the smallest energy filter time of the four channels SLOWLENGTH SLOWGAP 2 FILTERRANGE Igor controls Window Width in the Coincidence tab C global ACTUAL COINCIDENCE WAIT ControlTask to apply change 5 SYNCHWAIT Controls run start behavior When set to 0 the module simply starts or resumes a run in response to the corresponding request When set to 1 the module will pull down a wire OR line in the PXI e backplane during run initialization and start acquisition only when the line goes high again This ensures that the last module ready to actually begin da
65. en at low count rates dead time 10 Best energy resolutions are typically obtained at values of 3 to 4 in 16bit signed integer format and this parameter does not need to be adjusted afterwards Constraints LOG2BWEIGHT gt 65520 equiv 16 LOG2BWEIGHT lt 65535 equiv 1 and additionally LOG2BWEIGHT 0 Igor controls Baseline Averaging in the Advanced tab C global BLAVG ControlTask to apply change none PREAMPTAUA PREAMPTAUB High word and low word of the preamplifier s exponential decay time The two variables are used to store the value with higher precision The time 4s measured in Ss The two words are computed as follows PREAMPTAUA floor 4b PREAMPTAUB 65536 1 PreampTauA To recover quise gg PREAMPTAUA PREAMPTAUB 65536 Constraints TAU gt 1 65536 us TAU lt 65535 us Igor controls Tau in the Energy tab C global TAU ControlTask to apply change none 64 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved This ends the block of channel input data Note that there are four equivalent blocks of input channel data one for each Pixie 4 input channel 4 3 Module output parameters We now show the output variables again beginning with module variables and continuing afterwards with the channel variables The output data block begins at the address 0x4100 Note however that this address could change The output data block comprises of 160 words 1 block of 32 is rese
66. etermined and written into the list mode buffer At the end of the task the list mode buffer holds the following data Its 8192 words are divided up equally amongst the four channels Data for channel 0 occupy the lowest 2048 words followed by data for channel 1 etc The first entry for each channel s data block is for a DAC value of 0 the last entry is for a DAC value of 65504 In between entries the DAC value is incremented in steps of 32 An examination of the results will reveal a linearly rising or falling response of the ADC to the DAC increments The slope depends on the trigger polarity setting i e bit 5 of the channel control and status register A CHANCSRA For very low and very big DAC values the ADC will be driven out of range and an unpredictable but constant response is seen From the sloped parts a user program can find the DAC value that is necessary for a desired ADC offset It is recommended that for unipolar signals an ADC offset of 1638 units is chosen For bipolar signals like the induced waveforms from a segmented detector the ADC offset would be 8192 units i e midway between 0 and 16384 A user program would use the result from the calibration task to find set and program the correct offset DAC values Since the offset measurement has to take the preamplifier offset into account this measurement must be made with the preamplifier connected to the Pixie 4 input The control task makes 16 measurements at each DA
67. ewer a dynamic link library DLL or static library or can be used by a standalone C program The two latter options can be used by advanced users to integrate Pixie modules into their own data acquisition systems Sample make files and MS Visual Studio project files version 2005 are included in the distribution The following table summarizes the required files for these options Table 2 3 Options for compiling the Pixie C Driver Required Files Option boot h defs h globals h sharedfiles h utilities h PciRegs h PciTypes h PexApi h Plx h PLX sysdep h PIxApi h PIxApi lib PlxTypes h Reg9054 h PlxIoctl h PlxApi650 dll PIxNetloctl h PIxNetTypes h plxdefck h plxstat h pci Jungo h Boot c eeprom c pixie c c utilities c ua par io c Files required for all options Additional files for a dynamic link library pixie4VI DLL c DLL or static library pixie4 iface h IgorXOP h VCExtralncludes h XOP h XOPResources h bed XOPStandardHeaders h Additional files ee XOPSupport h XOPSupport lib for Igor XOP nA CER i XOPStructureAlignmentReset h IGOR lib pm XOPStructureAlignmentTwoByte h XOPSupportWin XOPWinMacSupport h XOPWMWinMacSupport h Additional files for standalone program e g sample c sample c or equivalent SystemConfig c sample h or equivalent There are two compiler switches options that have to be set by the makefiles or project files COMPILE IGOR_XOP if defined enable
68. for Pixie 500 and Pixie 500 Express Igor controls Energy Filter Rise Time in the Energy tab C global ENERGY RISETIME 54 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved ControlTask to apply change 5 SLOWGAP The flat top of the energy filter also called gap time depends on SLOWGAP Energy Filter Flat Top SLOWGAP 2 FILTERRANGE dt Constraints SLOWGAP gt 3 SLOWLENGTH SLOWGAP lt 127 dt 13 3ns for Pixie 4 8ns for Pixie 500 and Pixie 500 Express Igor controls Energy Filter Flat Top in the Energy tab C global ENERGY FLATTOP ControlTask to apply change 5 FASTLENGTH The rise time of the trigger filter depends on FASTLENGTH Trigger Filter Rise Time FASTLENGTH dt Constraints FASTLENGTH gt 2 FASTLENGTH FASTGAP lt 63 dt 13 3ns for Pixie 4 8ns for Pixie 500 and Pixie 500 Express FASTLENGTH is computed by the C library from the Trigger Filter Rise Time value entered by the user in the Trigger tab in Igor Igor controls Trigger Filter Rise Time in the Trigger tab C global TRIGGER RISETIME ControlTask to apply change 5 FASTGAP The flat top of the trigger filter depends on FASTGAP Trigger Filter Flat Top FASTGAP dt Constraints FASTGAP gt 0 FASTLENGTH FASTGAP lt 63 dt 13 3ns for Pixie 4 8ns for Pixie 500 and Pixie 500 Express FASTGAP is computed by the C library from the Trigger Filter Flat Top value entered by the user in the Trigger tab in Igor
69. ger filter FPGAs The following is a list of control tasks that will be of interest to the programmer To start a control task set RUNTASK 0 and choose a CONTROLTASK value from the list below Then start a run by setting bit 0 in the control and status register CSR Control tasks respond within a few hundred nanoseconds by setting the RUNACTIVE bit 13 in the CSR The host can poll the CSR and watch for the RUNACTIVE bit to be deasserted AII control tasks indicate task completion by clearing this bit Execution times vary considerably from task to task ranging from under a microsecond to 10 seconds Hence polling the CSR is the most effective way to check for completion of a control task Control Task 0 SetDACs Write the GAINDAC and TRACKDAC values of all channels into the 69 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved respective DACs Reprogramming the DACs is required to make effective changes in the values of the variables GAINDAC 0 3 TRACKDAC10 3 Control Task 1 Connect inputs Close the input relay to connect the Pixie electronics to the input connector Pixie 4 only Control Task 2 Disconnect inputs Open the input relay to disconnect the Pixie electronics from the input connector Pixie 4 only Control Task 3 Ramp offset DAC This task is used for calibrating the offset DAC For each channel the offset DAC is incremented in 2048 equal size steps At each DAC setting the DC offset is d
70. he DSP variable DBLBUFCSR to 1 and clear MODCSRA bit I in all modules During run poll the CSR by calling AcquireData with Runtype Ox40FF which returns the full CSR value Bit 14 is set to I by the DSP when data is ready Bit 13 is 1 while the run is active if it is zero the run ended because both EM blocks are filled To handle the possibility of stopped runs properly the polling routine should execute a readout whenever bit 14 is 1 independent of bit 13 The readout will clear bit 14 If bit 13 is zero perform an additional readout for the remaining data As an example see the Pixie RC CheckRun routine in the Igor interface To read out first read the WordCount Register the CSR and the DSP output parameters EMwords and EMwords2 Compute the number of 16 bit words in blocks 1 and 2 as Nw16 1 EMwords 65536 EMwords 1 Nw16 2 EMwords2 65536 EMwords2 1 If CSR bit 10 1 data is in block 1 else data is in block 2 This bit is not changed for the last data transfer before a run 1s stopped so in readouts when the run is stopped read from the other block The readout itself follows the usual procedure in Pixie IOEM of a setting bit 2 in the CSR to request access to the EM b waiting for CSR bit 7 to be clear c reading Nw32 1 or Nw32 2 32 bit words from block 1 or block 2 and finally d clearing bit 2 of the CSR again Number of words and address are defined as follows Nw32 1 2 Nw16 1 2 add I if Nw16 1
71. he output buffer 8K words Event length EVENTHEADLEN X CHANHEADLEN TRACELENGTH x good MAXEVENTS max 8K BUFHEADLEN Event length Set MAXEVENTS 0 if you want to switch off this feature e g when logging spectra or when there is no need to enforce a fixed number of events In particular if 4 channels are good and MAXEVENTS is computed accordingly but the majority of events have only a single channel with a pulse the buffer is only filled up to about 1 4 when MAXEVENTS is reached So in this case it would be more efficient to disable the MAXEVENT limit by setting it to zero The parameter is ignored in runtypes 0x301 and 0x400 Igor controls Events buffer in the Run Control tab C global MAX EVENTS The C library enforces an upper limit for MAXEVENTS ControlTask to apply change none 44 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved COINCPATTERN The user can request that certain coincidence anticoincidence patterns are required for the event to be accepted With four channels there are 16 different hit patterns and each can be individually selected or marked for rejection by setting the appropriate bit in the COINCPATTERN mask Consider the 4 bit hit pattern 1010 The two I s indicate that channel 3 MSB and channel 1 have reported a hit Channels 2 and 0 did not The 4 bit word reads as 10 decimal If this hit pattern qualifies as an acceptable event set bit 10 in the COINCPATTERN to 1 The 1
72. hed gate pulse and the local fast trigger Bit 11 4x traces Pixie 4 only If set each waveform sample contains the average of 4 ADC samples The time between waveform samples is 4x the ADC sampling time If this bit is enabled for channel 0 3 bit 4 7 in the List mode data RUNFORMAT word is set to indicate the 4x time scale Bit 12 Out of range to Veto Pixie 4 only If set whenever the signal goes out of range on the lower limit 0 the module issues a signal on the VETO backplane line for all modules Note Only one of bits 3 5 and 6 is meant to be set at the same time but this is not enforced Igor controls Checkboxes in the PARAMETER SETUP panel C global CHANNEL CSRC ControlTask to apply change 5 GAINDAC Reserved and not supported TRACKDAC This DAC determines the DC offset voltage The offset in volts displayed in Igor and contained in the C global VOFFSET can be calculated using the following formula Offset V 2 5V 32768 TRACKDAC 32768 Constraints TRACKDAC 0 TRACKDAC lt 65535 Igor controls Offset V in the OSCILLOSCOPE panel C global VOFFSET ControlTask to apply change 0 SGA The index of the relay combinations of the switchable gain amplifier For a given value of SGA the analog SGA gain is G 1 Rf Rg 2 with Rf 2150 120 SGA amp 0x1 gt 0 270 SGA amp 0x2 gt 0 560 SGA amp 0x4 gt 0 Rg 1320 100 SGA amp 0x10 gt 0 300 SGA amp 0x20 gt 0 8
73. hich are given in the variables AOUTBUFFER and LOUTBUFFER Next the user starts a data run and reads the results after the run has ended 6 Appendix B User supplied Igor code Starting in version 1 38 Igor contains a number of user procedures that are called at certain points in the operation These user procedures are contained in a separate Igor procedure file user ipf that is automatically loaded when opening the Pixie Viewer Pixie4 pxp By default the user procedures do nothing but they can be edited to perform custom functions It is recommended that the modified procedures be saved as a new procedure file user XXX ipf and the generic user ipf be removed killed from the main pxp file 6 1 Igor User Procedures The Igor user procedures called from the current version of the main code are listed below Function User Globals This function is called from InitGlobals It can be used to define and create global specific for the user procedures By default it creates a user variable UserVariant which can be used to track and identify different user procedure code variants Variant numbers Ox7FFF are reserved for user code written by XIA Function User StartRun This function is called at end of Pixie StartRun which is executed at beginning of a data acquisition run for runs with polling time gt 0 It can be used to set up customized runs i e initialize parameters etc Function User NewFileDuringRun
74. hopefully is a PDM The PDM uses this word to make a coincidence accept reject decision based on the hit pattern from all modules 47 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved Currently not implemented for the Pixie 500 Express Igor controls Checkboxes in the CHASSIS SETUP panel C global NNSHAREPATTERN ControlTask to apply change none CHANNUM The chosen channel number May be modified internally for tasks looping over all 4 channels or to pass on current channel to user code Should be set by host before starting controltask 4 and 6 to indicate which channel to operate on Previously HOSTIO was used in controltask 4 We recommend to always change CHANNUM when changing the channel that is addressed in the user interface Igor controls none C global none ControlTask to apply change none DBLBUFCSR A register containing several bits to control the double buffer ping pong Bit 0 Bit 1 Bit 2 Bit 3 mode to read out external memory In the future these control bits may be moved to the CSR register in the System FPGA Enable double buffer If this bit is set transfer list mode data to external memory in double buffer mode Must be set cleared for all modules in the system If set clear bit I of MODCSRA Set by host read by DSP Host read Host sets this bit after reading a block from external memory to indicate DSP can write into it again Set by host read and cleared by DSP reserved
75. ixie 500 Express list mode runs are type 0x400 uninterupted transfer of data to host List mode 0x400 output data is written as one file per module List mode 0x400 events are single channel records with a new data structure as described in the user manual However the same run tasks in Pixie Acquire Data are used to process list mode files and return data to a host program The file name list has been expanded to include files for Pixie 4 Pixie 500 and Pixie 500 Express N BOOT FILES 16 Pixie Acquire Data should always be called with a valid filename and the lower 12 bits set according to the runtype In the past this was not always required now it is used e g in Start Run to distinguish the different list mode types and write a file header in 0x400 list mode runs The number of DSP parameters has been increased to 512 was 416 Some parameters shifted position others have been removed Corresponding user global module and channel parameters have been removed as well see tables 3 5 b and c 2 Pixie API The Pixie API consists of a set of C functions for building various coincidence data acquisition applications It can be used to configure Pixie modules make MCA or list mode runs and retrieve data from the Pixie modules The API can be compiled as a WaveMetrics Igor XOP file which is currently used by the Pixie Viewer a dynamic link library DLL or a static library to 1 Pixie 4 Programmer s Manual V3 11 3 XIA
76. ke energy filter rise time or flat top The function used to change Pixie settings is Pixie User Par IO This function converts a user parameter like energy filter rise time in us into a number understood by the Pixie hardware or vice versa Pixie Get Par Idx and Pixie Get Par Name are the two functions employed to assist in using Pixie User Par IO when the Pixie 500e C library is linked dynamically to the user s application dll library In this case the names of the user controlled variables and their indexes in arrays are not accessible to the user s application The user therefore is lead to inquire the library regarding a particular parameter of interest either through an index or a string Another function Pixie Buffer IO is used to read data from DSP s internal memory to the host or write data from the host into the internal memory This is useful for diagnosing Pixie modules by looking at their internal memory values The other usage of this function is to read save copy or extract Pixie s configurations though its settings files In a multi module Pixie 4 system it is essential for the host to know which module or channel it is communicating to The function Pixie Set Current ModChan is used to set the current module and channel The detailed description of each function is given below 2 Pixie 4 Programmer s Manual V3 11 XIA 2014 All rights reserved Pixie Hand Down Names Syntax 532 Pixie Hand Down Names U8 Names
77. le 18 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved Run type 0x1000 Error Handling Handling None Invalid Pixie module number Check ModNum Failure to start the data run Reboot the module Run type 0x2000 None Run type 0x3000 Run type 0x4000 0 No run is in progress Run type 0x5000 Error Handling Failure to save histogram data to a Check the file name file Run type 0x6000 Error Handling Failure to save list mode data to a Check the file name file Run type 0x7000 EET 19 Pixie 4 Programmer s Manual V3 11 XIA 2014 All rights reserved Failure to read PSA values Check list mode data file Failure to read extended PSA values Check list mode data file Failure to locate events Check list mode data file Failure to read events Check list mode data file 0x79 Invalid list mode parse analysis request Check run type Run type 0x8000 Error Handling Handling None Failure to read out MCA spectrum from the file Check the MCA data file Run type 0x9000 Noe O Failure to read out LM section of external memor Reboot the module Failure to write to LM section of external memor Reboot the module Invalid external memory I O request Check the run type Usage example 32 retval U16 RunType U32 dummy 2 U8 ModNum RunType 0x1100 ModNum 0 retval Pixie Acquire Data
78. le This number will be written into the header of the list mode buffer to aid offline event reconstruction It is normally set by the settings file during the boot process Igor controls Slot Wave C global SLOT WAVE ControlTask to apply change none MODCSRA The Module Control and Status Register A Bit 0 reserved Bit 1 If set DSP acquires 32 data buffers in each list mode run and stores the data in external memory If not set only one buffer is acquired and the data is kept in local memory Must be set cleared for all modules in the system If set clear bit 0 of DBLBUFCSR Ignored for Pixie 500 Express 40 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 Bit 7 Bit 8 Bit 9 Bit 10 Bits 2 and 15 control trigger distribution over the backplane If neither bit 2 or bit 15 are set triggers are distributed only between channels of this module Otherwise triggers are distributed as follows ee Triggers are distributed within module only no connection to backplane Module shares triggers using bussed wire OR line In systems with less than 8 modules and no PXI bridge boundaries all modules sharing trigger should be set this way Module receives triggers from master trigger lines but uses neighboring lines to distribute triggers from right to left In systems with more than 7 modules and orPXI bridge boundaries all modules except the leftmost should be se
79. les The host computer communicates with the DSP by setting and reading a set of variables called DSP I O variables These variables totally 512 unsigned 16 bit integers sit in the first 512 words of the data memory The first 256 words which store input variables are both readable and writeable while the remaining 256 words which store pointers to various data buffers and run summary data are only readable The exact location of any particular variable in the DSP code will vary from one code version to another To facilitate writing robust user code we provide a reference table of variable names and addresses with each DSP code version Included with the software distribution is a file called PXIcode var or P500code var P500e var It contains a two column list of variable names and their respective addresses Thus you can write your code such that it addresses the DSP variables by name rather than by fixed location It should come as no surprise that many of the DSP variables have meaningful values and ranges depending on the values of other variables A complete description of all interdependencies can be found in Section 4 AII of these interdependencies have been taken care of by the Pixie API So instead of directly setting DSP variables users only need to set the values of those global variables defined in Table 3 5 The API will then convert these values into corresponding DSP variable values and download them into the DSP data memory
80. lications buffers might fill slowly so it might take a long time to get 16 buffers for the next update of list mode data For more frequent updates set MAXEVENTS to a smaller number so that the 8K buffers are only partially filled before transfer to the external memory The transfer dead time time between last event in a filled buffer and the start of the next buffer is about 550us This includes resetting counters etc when resuming acquisition Buffer fill times depend on runtype length of traces and count rates Host readout times are typically 30ms per module but may be longer if the host PC is busy with other processes As long as the host reads out faster than 16 buffers are filled and transferred there is no readout dead time only the 550us transfer time between buffers Otherwise since 32 buffers are read out in less than twice the time of 16 buffers PCI setup takes longer than actual burst read the older 32x buffer mode may still be more efficient To use this function in Igor select the corresponding checkbox in the Run Tab Select the number of 16 buffer spills and start a run as usual The run finishes when the number of spills is reached but there is likely one extra partial spill that was in progress when Igor read the last spill and ended the run When programming modules directly make the following changes 80 Pixie 4 Programmer s Manual V3 11 XIA 2014 All rights reserved To enable set bit 0 of t
81. lobal CHANNEL CSRB 51 Pixie 4 Programmer s Manual V3 11 XIA 2014 All rights reserved ControlTask to apply change none CHANCSRC Control and status register C Bit 0 Bit 1 Bit 2 Bit 3 Bit 4 Bit 5 Bit 6 Bit 7 Bit 8 Bit 9 GFLT polarity Pixie 4 only Controls polarity of GFLT to be considered present for accepting events i e GFLT must be zero to record events instead of 1 GATE acceptance polarity Pixie 4 only Controls polarity of GATE to be considered present for accepting events i e the GATE status latched at the time of the rising edge of the detector pulse must be Zero to record events instead of 1 Use GFLT for GATE Pixie 4 only If set use GFLT input for fast validation of signal rising edge of pulse Disable pileup inspection If set pulses are accepted even if a pileup was detected Disable out of range rejection Pixie 4 only If set pulses are accepted even if the ADC input goes out of range This can be used for detectors with occasional very large pulses The energy filter essentially saturates for the time the signal is out of range which means the reported energy is a measure of how long the signal is out of range and thus a coarse measure of the energy assuming exponential decay Invert pileup inspection If set only accept events with pileup May be useful to capture double pulse events Pause pileup inspection If set disable pileup inspection for 32 clock
82. measured time Convert the four words into a time using the formula GDT GDTX 64K 3 GDTA 64K 2 GDTB 64K GDTC dt dt 13 3ns 16 for Pixie 4 8ns 32 for Pixie 500 and Pixie 500 Express ICR Pixie 4 only ICR is an averaged measure of the current input count rate It is updated if a run is in progress or not The averaging is implemented such that at every update Averagenew Average Number fast triggers in update period 2 The value reported in the variable ICR is equal to 2 Averagenew Updates occur every 32 64K clock cycles Thus to compute the rate in counts s the value in ICR has to be divided by 32 64K 13 3ns The reported value is precise to about 50 counts s with a maximum count rate of about one million counts s OORF Pixie 4 only OORF is an averaged measure of the fraction of time the channel is out of range It is updated if a run is in progress or not The averaging is implemented such that at every update Averagenew Averageoa Time out of range 64 2 The value reported in the variable OORF is equal to 2 Averagenew Updates occur every 32 64K clock cycles Thus to compute the out of range fraction in percent the value in OORF has to be multiplied by 100 64K 4 5 Control Tasks The DSP can execute a number of control tasks which are necessary to perform functions that are not directly accessible from the host computer The most prominent tasks are those to set the DACs and program the trig
83. mes is given in Table 3 5 Return values Error Handling 0 Success None 4 1 Invalid name Check the second parameter Name Usage example S32 retval download system parameter names define System Parameter Names first retval Pixie Hand Down Names System Parameter Names SYSTEM if retval lt 0 error handling download module parameter names define Module Parameter Names first retval Pixie Hand Down Names Module Parameter Names MODULE if retval lt 0 error handling download channel parameter names define Channel Parameter Names first retval Pixie Hand Down Names Channel Parameter Names CHANNEL if retval lt 0 error handling download boot file names define All Files first retval Pixie Hand Down Names All Files ALL FILES if retval lt 0 error handling 4 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved Pixie Boot System Syntax 532 Pixie Boot System U16 Boot Pattern The Pixie 4 boot pattern Description Use this function to boot all Pixie modules in the system Before booting the modules it scans all PXI e crate slots and finds the address for each slot where a Pixie module is installed Parameter description Boot Pattern is a bit mask used to control the boot pattern of Pixie modules Bit 0 Boot communication FPGA Bi
84. mited to XWAIT 13 N 5 If XWAIT gt 12 a filter is implemented during the acquisition to return each data point as the average over XWAIT 3 5 samples In a test debug mode this parameter also controls how many extra clock cycles the DSP waits when reading extra long waveforms in real time from the ADC register rather than out of the FIFO memory This occurs when acquiring data in list mode and asking for trace lengths longer than FIFOlength 1024 which is possible if the C library s tests are bypassed The time between recorded samples is then T 3 XWAIT 13 3ns for Pixie 500 Express aT XWAIT 5 13 3ns Constraints XW AIT must be a power of 2 between 1 and 8192 60 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved If XWAIT gt 1 a filter is implemented during the acquisition to return each data point as the average over XWAIT samples Igor controls dT in the OSCILLOSCOPE C global XDT ControlTask to apply change none XAVG Only used in Controltask 0x84 for reading untriggered traces XAVG stores the weight in the geometric weight averaging scheme to remove higher frequency signal and noise components The value is calculated as follows for Pixie 4 and Pixie 500 For a given dT in 38 calculate the integer intdt dT 0 0133 If intdt gt 13 XAVG floor 65536 intdt 3 5 If intdt lt 13 XAVG 65535 for Pixie 500 Express XAVG log XWAIT Igor controls dT in the OSCILLOSCOPE
85. o a file retval Pixie Acquire Data 0x6100 User Data DataFile modnum if retval O k if k gt Nruns break while 1 read out the MCA Error handling spectrum and put it to array User Data retval Pixie Acquire Data 0x9001 User Data DataFile modnum if retval O Error handling 37 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved To process the list mode data after it is saved to a file the Pixie API provides several utility routines to parse the list mode data and read out the waveform energy of each individual trace or PSA values The code below shows how to read waveforms from a list mode file An Example Code Illustrating How to Parse List Mode Data 532 retval U8 direction modnum channum i U32 List Data 2 PRESET MAX MODULES list mode trace information for the maximum possible number of modules in a system char DataFile C XIA Pixie4 PulseShape Data bin U32 totaltraces total number of traces in the list mode data file U32 traceposlen point to positions of the traces in the file U32 Trace0 point to the first trace in the file direction 0 download modnum 0 Module 0 channum 0 Channel 0 parse list mode file retval Pixie Acquire Data 0x7001 List Data DataFile modnum if retval 0 Error handling totaltraces 0 for i 0 i PRESET M
86. of events detected by the fast filter is FAST PEAKS FASTPEAKSX 64K 2 FASTPEAKSA 64K FASTPEAKSB FTDTX FTDTA FTDTB FTDTC Fast Trigger dead time is the time the fast trigger output was above threshold and thus not ready to detect further triggers as measured by the trigger filter FPGA See the user manual for a description of the measured time Convert the four words into a time using the formula note missing factor 16 FTDT FTDTX 64K 3 FTDTA 64K 2 FTDTB 64K FTDTC dt dt 13 3ns for Pixie 4 8ns for Pixie 500 and Pixie 500 Express SFDTX SFDTA SFDTB SFDTC Slow Filter Dead Time is the time the associated with each pulse that prohibited acquisition of a second pulse for example due to pileup inspection or DSP readout See the user manual for a description of the measured time Convert the four words into a time using the formula SFDT SFDTX 64K 3 SFDTA 64K 2 SFDTB 64K SFDTC dt dt 13 3ns 16 for Pixie 4 8ns 32 for Pixie 500 and Pixie 500 Express GCOUNTX GCOUNTA GCOUNTB The number of gate pulses for this channel high low GCOUNT GCOUNTX 64K 2 GCOUNTA 64K GCOUNTB NOUTX NOUTA NOUTB The number of output counts in this channel high low NOUT NOUTX 64K 2 NOUTA 64K NOUTB 68 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved GDTX GDTA GDTB GDTC Gate Dead Time is the time during which a channel was gated See the user manual for a description of the
87. om the DSP into the external memory testing list mode data transfers The data written is as follows Word Value Notes 16bit o 18002 Works as buffer length MODNUM Can be used to identify a module by writing MODNUM through CAMAC and reading the EM through USB LOXAAAA 3 105558 OXCCCC GE UNEEEEEEMEEEEMEMEMEMEMEMEEN 6 Jouu S O 7 JOBBER 8 Ox8888 Ee OT qo cx ooo M Repeat above words 2 9 for 999 times 8104 testing odd sized buffer transfers 8207 testing odd sized buffer transfers ControlTask 26 Test histogramming This routine is used to write a test pattern to the external memory by incrementing bin N for N times for bins 0 4K The result is a spectrum in channel 0 that forms a line with Ncounts bin number for bins 0 4K This procedure will take several seconds to complete ControlTask 7 21 23 25 26 127 reserved for DSP tasks ControlTask 128 Measure baselines and compute BLCUT for all modules 72 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved This routine is used to compute the BLCUT value for all modules The C library will call ControlTask 6 in the DSP for each channel and module compute baselines and set BLCUT to 4x standard deviation ControlTask 129 Find values of for all modules This routine is used to compute the decay time for all channels and modules The C library will run a tau finder routine on every channel and write the new v
88. one BLCUT This variable sets the cutoff value for baselines in baseline measurements If BLCUT is not set to zero the DSP checks continuously each baseline value to see if it is outside of the limit set by BLCUT If the baseline value is within the limit it will be used to calculate the average baseline value Otherwise it will be discarded To reduce processing time set BLCUT to zero to not check baselines ControlTask 6 can be used to measure baselines The host computer can then histogram these baseline values and determine the appropriate value for BLCUT for each channel according to the standard deviation of the averaged baseline value This is done automatically in the C library every time the decay time or the energy filter rise time or flat top is changed setting BLCUT to 4 times the standard deviation The value of BLCUT depends on decay time gain filter settings and the noise from the detector Automatically computed values below 15 are suspicious and 15 is used instead Values have to be measured as above and can not be derived easily from first principles Constraints BLCUT gt 0 BLCUT lt 32767 Igor controls Baseline Cut in the Advanced tab C global BLCUT ControlTask to apply change none Calling Controltask 128 in the C library automatically determines BLCUT BASELINEPERCENT This variable sets the target DC offset level for automatic adjustment ControlTask 0x83 in terms of the percentage of the ADC r
89. ring G root results StopTime Stop time run statistics panel Wave root results MCAchO Channel 0 histogram Wave root results MCAch1 Channel 1 histogram Wave root results MCAch2 Channel 2 histogram Wave root results MCAch3 Channel 3 histogram Wave root results MCAsum Sum histogram Wave root results trace0 channel 0 list mode trace Wave root results tracel channel 1 list mode trace Wave root results trace2 channel 2 list mode trace Wave root results trace3 channel 3 list mode trace Wave root results eventposlen contains trace location in list mode file Wave root results eventwave contains data for selected list mode event NewDataFolder o root user create the folder for variables defined by user Variable G root user UserVersion the version of the user function calls defined by XIA Variable G root user UserVariant the variant of the code written by the user The format of the wave root results eventwave is as follows Position Content 0 1 Jen Lo event location in file location of corresponding buffer header in file length of event in file tracelength for channel 0 3 12 buffer header see user s manual 13 15 event header see user s manual 16 24 channel header for channel 0 see user s manual 79 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved 25 33 channel header for channel 1 34 42 channel header for channel 2 43 51 channel header for channel 3
90. rved for module data 4 blocks of 32 words each hold channel data DECIMATION This variable is a copy of the input parameter FILTERRANGE It is copied as an output parameter for backwards compatibility REALTIMEA REALTIMEB The real time clock A B are the high and middle word of a 48 bit counter the lowest 16 bit are not visible as an output parameter The clock is zeroed on power up and in response to a synch request at run start INSYNCH 0 SYNCHWAIT 1 Compute the real time since boot or synchronization using the following formula RealTime RealTimeA 64K 2 RealTimeB 64K 13 3ns RUNTIMEX RUNTIMEA RUNTIMEB RUNTIMEC The 64 bit run time X A B C words are as for the 16bit numbers that combine into the total 64 bit time This time counter is active only while a data acquisition run is in progress Comparing the run time with the total time allows judging the overhead due to data readout Compute the run time using the following formula RunTime 13 3ns RUNTimeX 64K 3 RUNTimeA 64K 2 RUNTimeB 64K RUNTimeC TOTALTIMEX TOTALTIMEA TOTALTIMEB TOTALTIMEC A timer to track the total time an acquisition was requested by the host RUNTIME excludes the time waiting for host readout TOTALTIME is the closest measure to the true lab time passed since the most recent new run command the first spill in a series X A B C words are as for the RunTime Compute the total time using the following formula TotalTime
91. s 1 up to six values are incorporated overwriting the XIA PSA value the USER PSA value the GSLT time and the reserved word in the channel header If the run type compresses the standard nine channel header words the number of user return values is reduced accordingly i e only 2 words are available in RunTask 0x102 and no words in RunTask 0x103 When entering UserChannel a number of global variables have been set by the DSP These are listed in the file INTRFACE INC as externals Register usage For register usage restrictions see the file INTRFACE INC 5 5 Debugging tools Besides the debugging tools that are accessible through the Pixie 4 Viewer it is also possible to download data into the Pixie data buffers and call the event processing routine This allows for an in situ test of the newly written code and allows exploring the valid parameter space systematically or through a Monte Carlo from the host computer For this to work the module has to halt the background activity of continuous base line measuring Next data have to be 76 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved downloaded and the event processing started When done the host can read the results from the known address The process is fairly simple The host writes the length of the data block that is to be downloaded into the variable XDATLENGTH Then the data are written to the linear output buffer the address and length of w
92. s in units of clock cycles 13 3ns for both Pixie 4 and Pixie 500 Currently not implemented for Pixie 500 Express Constraints COINCDELAY 0 COINCDELAY lt 65533 Igor controls Delay in the Coincidence tab C global none ControlTask to apply change 5 RESETDELAY This variable sets the timeout to restart processing in the trigger filter FPGA automatically after it captured an event but has not received event validation In most circumstances event capture constitutes validation and this timeout does not apply However if a channel is not trigger enabled or responds to group triggers only a local event by itself is not valid so the channel waits for RESETDELAY clock cycles to receive external validation In other words RESETDELAY is the window for trigger disabled channels to be included in an event ater triggered by another channel Constraints RESETDELAY 0 RESETDELAY lt 65535 The default value is max 29 CD 4 and should normally not be changed by the user CD is the value of COINCDELAY in processing clock ticks CD COINCDELAY for the Pixie 4 CD COINCDELAY 125 75 for the Pixie 500 Ignored for Pixie 500 Express Igor controls none C global none ControlTask to apply change 5 TRACELENGTH This variable determines the length of captured waveforms in list mode runs in clock cycles TRACELENGTH Trace Length dt Constraints TRACELENGTH gt 0 TRACELENGTH lt TLMAX but see below dt 13
93. s sections of the code used for compiling the Igor xop It must not be defined for compilation of the dll or sample code 26 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved e XIA WINDOZE if defined enables sections of the code used for compiling code for Windows XIA Linux if defined enables sections of the code used for compiling code for Linus The two options are exclusive The Pixie 4 C library is ANSI C compatible as much as possible but a number of non standard functions are used These are 19 Sleep Throughout the code the function Pixie Sleep is used to wait for a time in ms In utilities c this function is implemented using the Microsoft Visual C function S eep For other compilations e g in Linux this function has to implemented differently To compile under Linux files from the PLX software development kit have to be present This SDK is available from PLX www plxtech com and not distributed by XIA The Linux make file expects the complete SDK to be present under PixieClib Linux 27 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved 3 Control Pixie Modules via C program 3 1 Initializing We describe here how to initialize Pixie modules in a PXI e chassis using the functions described in Section 2 As an example we assume two Pixie 4 modules residing in slot 3 and 4 respectively Users are also encouraged to read the sample C code shipped with the API
94. t 1 Boot signal processing FPGA Bit 2 Boot DSP Bit 3 Load DSP parameters Bit 4 Apply DSP parameters call Set DACs and Program FIPPI Under most of the circumstances all the above tasks should be executed to initialize the Pixie modules i e the Boot Pattern should be Ox1F Programs executing only a subset of fucntions for example starting a list mode run after the Pixie modules have been booted by another program may have to use Boot Pattern 0x0 to initialize the communication without rebooting the modules Return values Error Handling None Unable to scan crate slots Check PXI slot map Unable to read communication FPGA configuration Rev Check comFPGA file B Unable to read communication FPGA configuration Rev Check comFPGA file C Unable to read signal processing FPGA configuration Check SPFPGA file Unable to read DSP executable code Check DSP code file Unable to read DSP parameter values Check DSP parameter file Unable to initialize DSP parameter names Check DSP var file 8 Failed to boot all modules present in the system Check Pixie modules 1 2 3 4 5 7 Usage example S32 intval retval Pixie_Boot_System 0x1F 5 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved if ret lt 0 error handling 6 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved Pixie User Par IO Syntax 532 Pixie User Par IO double User P
95. t this way Module puts own triggers and triggers received from right neighbor on the master trigger lines and responds to triggers on master trigger line In systems with more than 7 modules and orPXI bridge boundaries the leftmost module should be set this way If set compute sum of channel energies for events with more hits in more than one channel and put into addback spectrum Ignored for Pixie 500 Express If set spectra for individual channels contain only events with a single hit Only effective if bit 3 is set also Ignored for Pixie 500 Express If set use signal on front panel input DSP OUT between channel 1 and 2 and distribute on backplane to all modules as Veto signal GFLT Note that only one module may enable this option to avoid a conflict on the backplane Ignored for Pixie 500 Express If set channel 3 s hit status contributes to the STATUS backplane line Ignored for Pixie 500 Express Polarity of front panel pulse counter Ignored for Pixie 500 Express reserved If set module writes the value of NNSHAREPATTERN to its left neighbor during ControlTask 5 using a PXI neighbor line The left neighbor should be a PXI PDM The values specifies which coincidence test is applied in the PDM Ignored for Pixie 500 Express Pixie 500 only If set buffer header and event header time stamps are in units of 2 ns 2 5ns in 400 MHz version If not set time stamps are in units of 13 33 ns The channel trigger time alw
96. ta taking will start the run in all modules Similarly the first module to end the run will stop the run in all modules Igor controls Checkboxes in the Run Control tab C global SYNCH WAIT ControlTask to apply change none INSYNCH InSynch is an input output variable It is used to clear the Pixie on board clock at the start of the data acquisition When INSYNCH is 1 no particular action is taken If this variable is 0 and SYNCHWAIT 1 then all system timers are cleared at the beginning of the next data acquisition run After run start INSYNCH is automatically set to 1 In this way all clocks in a multi module system are synchronized to within 3 clock cycles Igor controls Checkboxes in the Run Control tab C global IN SYNCH ControlTask to apply change none HOSTIO A 4 word data block that is used to specify command options Igor controls none C global none ControlTask to apply change none 46 Pixie 4 Programmer s Manual V3 11 XIA 2014 All rights reserved RESUME Set this variable to 1 to resume a data run otherwise set it to 0 Set to 2 before stopping a list mode run prematurely Ignored for Pixie 500 Express Igor controls none C global none ControlTask to apply change none FILTERRANGE The energy filter range downloaded from the host to the DSP It sets the number of ADC samples 2 FILTERRANGE to be averaged before entering the filtering logic The currently supported filer range in the signal pro
97. turn values Success 1 Failure to set DACs after writing DSP parameters Failure to pro parameters 3 Failure to program Fippi after loading parameters zi Failure to program Fippi after copying or extracting Reboot the module 10 Invalid module number Check ModNum 12 8 Failure to set DACs after copying or extracting settings Reboot the module Invalid I O direction Check direction Invalid I O type Check type Usage example 32 retval U8 type direction modnum modnum 0 Module number Download DSP parameters to the current Pixie module DSP Values is a pointer pointing to the DSP parameters no need to specify file name here direction 0 Write type 0 DSP I O values retval Pixie Buffer IO DSP Values type direction modnum if retval 0 Error handling Read DSP memory values from the current Pixie module Memory Values is a pointer pointing to the memory block no need to specify file name Here 24 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved direction 1 Read type 1 DSP memory values retval Pixie Buffer IO Memory Values type direction modnum if retval 0 Error handling 25 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved Options for Compiling Pixie API The Pixie API can be compiled as either a WaveMetrics Igor XOP file used by the Pixie Vi
98. uld be started as a NEW run This clears all histograms and run statistics in the memory Once the data has been read out you can RESUME running Each RESUME run will acquire another either 32 or I 8K buffers of data depending on which buffer has been chosen In a RESUME run the histogram memory is kept intact and you can accumulate spectra over many runs The example code shown below illustrates this In the Pixie 500 Express there is only one data buffer the 256 MB SDRAM FIFO Runs do not stop and resume data is continuously added to the SDRAM and transferred to a 2MB buffer on the host PC The host hast to check periodically if the 2MB buffer is filled and write the data to file For a description of the list mode data formats see section 4 2 of the user manual 35 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved An Example Code Illustrating How to Access List Mode Data Pixie 4 and Pixie 500 532 retval U8 direction modnum channum U32 User Data 131072 an array for holding the MCA spectrum data of 4 channels Ul6 k Nruns char DataFile C XIA Pixie4 PulseShape Data bin direction 0 download modnum 0 Module 0 channum 0 Channel 0 Nruns 10 10 repeated list mode runs k 0 initialize counter start a general list mode run retval Pixie Acquire Data 0x1100 User Data DataFile modnum if retval lt 0 Error handling do
99. unTask 257 0x101 requests a compressed list mode run for Pixie 4 or Pixie 500 Both Level 1 buffer and I O buffer are used in this RunTask but no traces are written into the I O buffer Nine words of results including time of arrival energy XIA pulse shape analysis user pulse shape analysis etc are written into the I O buffer for each channel RunTask 258 0x102 requests a compressed list mode run for Pixie 4 or Pixie 500 The only difference between RunTask 258 and 257 is that in RunTask 258 only four words of results time of arrival energy XIA pulse shape analysis user pulse shape analysis are written into the I O buffer for each channel RunTask 259 0x103 requests a compressed list mode run for Pixie 4 or Pixie 500 The only difference between RunTask 259 and 257 is that in RunTask 259 only two words of results time of arrival and energy are written into the I O buffer for each channel RunTasks 512 515 0x200 0x203 are no longer supported RunTask 769 0x301 requests a MCA run The raw data stream is always sent to the level 1 buffer independent of MODCSRA The data gathering interrupt routine fills that buffer with raw data while the event processing routine removes events after processing If the interrupt routine finds the level 1 buffer to be full it will ignore events until there is room again in the buffer The run will not abort due to buffer full condition This run type does not write data to the I O buffer
100. ving to rely on real signal sources 5 3 Interfacing user code to XIA s DSP code When the DSP is booted it launches a general initialization routine to reach a known and useful state As part of this process a routine called UserBegin is executed It is used to communicate addresses and lengths of buffers local to the user code to the host The host finds this information in the USEROUT 16 buffer described in the main section of this document The calling of UserBegin is not maskable All other functions that are part of the user interface will be called only if bit 0 of MODCSRB is set at the time When a run starts the DSP executes a run start initialization during which it will call UserRunlnit It may be used to prepare data for the event procesing routines 74 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved When events are processed by the DSP code it may call user code in two different instances Events are processed one channel at the time For each channel with data UserChannel is called at the end of the processing but before the energy is histogrammed UserChannel has access to the energy the acquired wave form the trace and is permitted one return value This is the routine in which custom pulse shape analysis will be performed After the entire event consisting of data from one to four channels has been processed the function UserEvent may be called It may be used in applications in which data have to
101. wnload system parameter VALUES initialized above to API d 0 direction download m 0 Module 0 G0 Channel 0 retval Pixie User Par IO System Parameter Values NUMBER MODULES SYSTEM d m c if retval lt 0 Error handling retval Pixie User Par IO System Parameter Values OFFLINE ANALYSIS SYSTEM d m C if retval lt 0 Error handling retval Pixie User Par IO System Parameter Values AUTO PROCESSLMDATA SYSTEM d m c if retval lt 0 Error handling retval Pixie User Par IO System Parameter Values MAX NUMBER MODULES SYSTEM d m c if retval lt 0 Error handling retval Pixie User Par IO System Parameter Values KEEP CW SYSTEM d m C if retval lt O Error handling retval Pixie User Par IO System Parameter Values SLOT WAVE SYSTEM d m c if retval lt 0 Error handling Note System Parameter Values contains entries for module 0 and 1 slot 3 and 4 the last command argument SLOT WAVE applies both boot Pixie 4 modules retval Pixie Boot System 0x1F if retval lt 0 Error handling set current module and channel number Pixie Set Current ModChan 0 0 30 Pixie 4 Programmer s Manual V3 11 3 XIA 2014 All rights reserved 3 2 Setting DSP variab
102. xie 500 Express Igor controls 7race Delay in the Waveform tab C global TRACE DELAY ControlTask to apply change 5 FTPWIDTH Removed GATEDELAY GATEWINDOW These variables set the coincidence window for the Gate signal to reject events At the rising edge of the Gate signal and internal Gate status bit goes high for the duration of GATEWINDOW A GATEDELAY after a fast trigger the status bit is latched into GATEBIT GATEBIT can be used to 59 Pixie 4 Programmer s Manual V3 11 XIA 2014 All rights reserved reject events in the FPGA and it is reported in the hit pattern in the list mode data stream for offline processing if no online rejection is desirable GATEWINDOW Gate Window dt GATEDELAY Gate Delay dt Constraints GATEWINDOW gt I GATEWINDOW lt 255 GATEDELAY gt I GATEDELAY lt 255 GATEDELAY lt PEAKSEP 2 FILTERRANGE for online rejection only dt 13 3ns for Pixie 4 8ns for Pixie 500 and Pixie 500 Express Ignored for Pixie 500 Express Igor controls Gate Delay Gate Window in the Gate tab C global GATE WINDOW GATE DELAY ControlTask to apply change 5 XWAIT Extra wait states XWAIT is used when acquiring untriggered traces in a control run with ControlTask 0x84 e g the traces in the Igor oscilloscope display The time T between data points in the output buffer is for Pixie 4 and Pixie 500 aT XWAIT 13 3ns Constraints XWAIT gt 4 XWAIT lt 65533 If XWAIT gt 12 it is li

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