Spectrum Brands MC.31XX Fifo Mode, General Information, Background Fifo Read, Speed Limitations

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FIFO Mode

Overview

 

 

FIFO Mode

Overview

General Information

The FIFO mode allows to record data continuously and trans- fer it online to the PC (acquisition boards) or allows to write data continuously from the PC to the board (generation boards). Therefore the on-board memory of the board is used as a continuous buffer. On the PC the data can be used for any calculation or can be written to hard disk while recording is running (acquisition boards) or the data can be read from hard disk and calculated online before writing it to the board.

FIFO mode uses interrupts and is supported by the drivers on 32 bit operating systems like Window 9x/ME, Windows NT/2000/XP or Linux. Start of FIFO mode waits for a trigger event. If you wish to start FIFO mode immediately, you may use the software trigger.FIFO mode can be used together with the options Multiple Recording/Replay and Gated Sampling/Replay. Details on this can be found in the appropriate chapters about the options.

Background FIFO Read

On the hardware side the board memory is spilt in two buffers of the same length. These buffers can be up to half of the on-board memory in size. In addition to the hardware buffers the driver holds up to 256 software buffers of the same length as the hardware buffers are. When- ever a hardware buffer is full with data the hardware generates an interrupt and the driver transfers this hardware buffer to the next software buffer that is available. While transfering one buffer to the PC, the other one is filled up with data. The driver is doing this job automatically in the background.

After the driver has finsihed transferring the data, the application software gets a signal and can process data (e.g stores data to hard disk or makes some calculations). After processing the data the application software tells the driver that he can again use the software buffer for acquisition data.

This two stages buffering has big advantages when running FIFO mode at the speed limit. The software buffers extremly expand the acquisi- tion time that can be buffered and protects the whole system against buffer overruns.

Speed Limitations

The FIFO mode is running continuously all the time. Therefore the data must be read out from the board (data acquisition) or written to the board (data generation) at least with the same speed that it is recorded/replayed. If data is read out from the board or written to the board slower, the hardware buffers will overrun at a certain point and FIFO mode is stopped.

One bottleneck with the FIFO mode is the PCI bus. The standard PCI bus is theoretically capable of transferring data with 33 MHz and 32 Bit. As a result a maximum burst transfer rate of 132 MByte per second can be achieved. As several devices can share the PCI bus this maximum transfer rate is only available to a short transfer burst until a new bus arbitration is necessray. In real life the continuous transfer rate is limited to approximately 100-110 MBytes per second. The maximum FIFO speed one can achieve heavily depends on the PC system and the operating system and varies from system to system.

The maximum sample rate one can run in continuous FIFO mode depends on the number of activated channels:

(c) Spectrum GmbH

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Contents English version April 27 MC.31xxPage Software Driver Installation Hardware InstallationIntroduction SoftwareProgramming the Board Fifo ModeAnalog Inputs Standard acquisition modesOption Gated Sampling Option Multiple RecordingOption Timestamp Option Extra I/OPreface IntroductionGeneral Information PrefaceIntroduction Different models of the MC.31xx seriesMC.3110 MC.3120 MC.3130 MC.3111 MC.3121 MC.3131 MC.3112 MC.3122 MC.3132 Digital inputs Additional optionsExtra I/O Option -XMF Introduction Additional optionsTimestamp StarhubSpectrum type plate Hardware information Block diagram Technical DataOrder information Dynamic ParametersIntroductionHardware information Order No DescriptionSystem Requirements Hardware InstallationInstalling the board in the system Hardware Installation Installing a board with digital inputs/outputsInstalling a board with extra I/O Option -XMF Mounting the wired boards Installing multiple boards synchronized by starhubHooking up the boards Only use the included flat ribbon cablesInstalling multiple synchronized boards Interrupt Sharing Software Driver InstallationInterrupt Sharing Software Driver Installation Windows InstallationWindows Version controlDriver Update Windows Driver Update Windows XP Software Driver InstallationWindows XP Adding boards to the Windows NT driver Software Driver Installation Windows NTWindows NT Overview LinuxNow it is possible to access the board using this device Installing the deviceDriver info Automatic load of the driverSoftware Overview SoftwareFirst Test with SBench Software OverviewHeader files ++ Driver InterfaceMicrosoft Visual C++ Borland C++ BuilderNational Instruments LabWindows/CVI Other Windows C/C++ compilersDriver functions Include DriversFunction SpcSetParam Software ++ Driver Interface Using the Driver under LinuxFunction SpcSetParam Function SpcSetData WindowsType definition Delphi Pascal Programming InterfaceInclude Driver ExamplesSoftware VBA for Excel Examples Visual Basic Programming InterfaceVisual Basic Examples Visual Basic Programming Interface Programming the Board Error handlingOverview Register tablesInitialization Example for error checkingStarting the automatic initialization routine PCI RegisterInstalled features and options Installed memoryHardware version Date of productionUsed type of driver Used interrupt lineProgramming the Board Initialization Driver versionExample program for the board initialization Powerdown and resetSpcpcimemsize SpcpciserialnoChannel Selection Analog InputsImportant note on channels selection Analog InputsRerouting information for module Channel reroutingSPCCHROUTE0 SPCCHROUTE1Input ranges Setting up the inputsRegister Value Direction Description Offset range Input offsetInput termination Automatical adjustment of the offset settingsOverrange bit Spcadjsave ADJUSER0 Spcadjautoadj AdjallProgramming Standard acquisition modesMemory, Pre- and Posttrigger Pretrigger = memsize posttriggerCommand register Starting without interrupt classic modeMaximum posttrigger in MSamples Minimum memsize and posttrigger in samplesStatus register Starting with interrupt driven modeStandard acquisition modes Programming Fast 8 bit mode Normal mode201100 Enables the fast 8 bit mode Data organizationReading out the data with SpcGetData Standard modeValue ’start’ as a 32 bit integer value Value ’len’ as a 32 bit integer valueProgramming General Information Fifo ModeBackground Fifo Read Speed LimitationsSoftware Buffers Programming Fifo ModeTheoretical maximum sample rate PCI Bus Throughput 60040 Read out the number of available Fifo buffersBuffer processing Fifo Mode ProgrammingAnalog acquisition or generation boards Digital I/O 701x or 702x or pattern generator boardsFifo acquisition example Example Fifo acquisition modeSpcfifostart SpcfifowaitSample format Standard internal sample rate Clock generationInternally generated sample rate Maximum internal sample rate in MS/s normal mode Using plain quartz without PLLExternal reference clock Clock generationDirect external clock External clockingMinimum external sample rate Maximum external samplerate in MS/sFifo External clock with dividerCHANNEL0 CHANNEL1 CHANNEL2 CHANNEL3 General Description Trigger modes and appendant registersSoftware trigger External TTL triggerEdge triggers Example on how to set up the board for positive TTL triggerTrigger modes and appendant registers Positive TTL triggerPositive and negative TTL trigger Pulsewidth triggersTTL pulsewidth trigger for long High pulses TTL pulsewidth trigger for short High pulsesTTL pulsewidth trigger for short LOW pulses TTL pulsewidth trigger for long LOW pulsesSpctriggermode Tmttlhighlp SpcpulsewidthOverview of the channel trigger registers Channel TriggerSpctriggermode Tmchannel TmchxoffSpctriggermode Tmchor TriggerlevelSPCTRIGGERMODE0 Tmchxoff SPCTRIGGERMODE2 TmchxoffSPCTRIGGERMODE0 Tmchxpos Reading out the number of possible trigger levelsSPCHIGHLEVEL0 Input ranges Triggerlevel ±50 mV ±100 mV ±200 mV ±500 mVChannel trigger on positive edge Detailed description of the channel trigger modesChannel trigger on negative edge Channel trigger on positive and negative edgeChannel pulsewidth trigger for long negative pulses Channel pulsewidth trigger for long positive pulsesTmchxposgsp Channel pulsewidth trigger for short positive pulsesChannel pulsewidth trigger for short negative pulses Channel steepness trigger for flat negative pulses Channel steepness trigger for flat positive pulsesChannel steepness trigger for steep negative pulses Channel steepness trigger for steep positive pulsesChannel window trigger for leaving signals Channel window trigger for entering signalsChannel window trigger for long outer signals Channel window trigger for long inner signalsChannel window trigger for short outer signals Channel window trigger for short inner signalsWhen using Multiple Recording pretrigger is not available Standard ModeOption Multiple Recording Recording modesTrigger modesOption Multiple Recording Resulting start delaysSpcmemsize SpctriggermodeOption Gated Sampling General information and trigger delayOption Gated Sampling SpcgateAlignement samples per channel End of gate alignementAllowed trigger modes Number of samples on gate signalOption Gated SamplingTrigger modes External TTL edge triggerExample program Option Gated Sampling Example programChannel trigger Spctriggermode TmttlposOption Timestamp StartReset modeTimestamp modes LimitsFunctions for accessing the data RefClock mode optionalTimestamp Status Reading out timestamp dataSpctimestampcount Data formatSpcGetData nr, ch, start, len, data Acquisition with Multiple Recording Standard acquisition modeExample programs Digital I/Os Option Extra I/OAnalog Outputs Channel directionProgramming example Option Extra I/O Programming exampleOption Digital inputs Bit Standard Mode Digital Inputs enabledSample format SpcreaddigitalDifferent synchronization options Synchronization OptionSynchronization with option cascading Synchronization with option starhubSet up the board parameters Setup order for the different synchronization optionsLet the master calculate it’s clocking Write Data to on-board memory output boards onlyDefine the boards for trigger master Example for data writingExample of board #2 set as trigger master 4a Define synchronization or triggerExample board number 0 is clock master Define the board for clock masterDefine the remaining boards as clock slaves Arm the boards for synchronizationWait for the end of the measurement Start all of the trigger master boardsRead data from the on-board memory acquisition boards only Restarting the board for another synchronized run2a Write first data for output boards Example of Fifo buffer allocationSpcsyncmasterfifo SpcsyncslavefifoGeneral information Additions for synchronizing different boards20xx 30xx 31xx 40xx 45xx 60xx 61xx 70xx 72xx Calculating the clock dividersBoard type 3122 3120 Setting up the clock divider40 MS/s Board type 3025 3131Delay in standard non Fifo modes Resulting delays using different boards or speedsDelay in Fifo mode Additions for equal boards with different sample ratesError Codes Error CodesError name Value hex Value dec Error description AppendixOption Digital inputs Pin assignment of the multipin connectorExtra I/O with external connectorOption -XMF Pin assignment of the multipin cable
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