AFM,STM,SPALEED

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GXSM - supported Hardware

January 2009: New and SPM dedicated Analog-IO: the SR2-A810 is ready for GXSM!

This is going to be an exiting year for GXSM. The upgrade of the old SR, the SR-Mk2 was out for a while but missing a SPM dedicated analog module, as the new 8 or 16 channel AIC board was just too slow and had too much in/out sample delays, i.e. unacceptable long loop delay for good use with SPM.

In summer 2008 the GXSM team discussed there needs with SoftdB and they agreed to design a SPM dedicated analog extension and the all new SR2-A810 was born. The GXSM team is very glad and happy about this and now all known SR features are seamless 1:1 available on the new but much more powerful SR2-A810 with 8 channels in and 8 channels out high precision/stability and high-speed analog IO. This is from now on the default GXSM/SPM hardware and all new main stream developments will go into this new platform. The old SR was serving very well for 5 years by now and still will be supported, but do not expect many new features.

GXSM-2.0 and SignalRanger DSP SR-Mk2 with SR2-A810 board: All SPM functionalities are fully supported by the 5th generation of DSP software design:

  • Full support of the "all new SignalRanger Mk2 with Analog810" (SR2-A810) (designed by SoftdB with input of the GXSM SPM team) by GXSM -- real world laboratory tested!
  • Complete GXSM functionvaility known by the previous SRanger is available, just at higher performance.
  • Citing Softdb: "The SR2-A810 will be available from beginning of February 2009".
  • In brief: USB-2.0, 300MHz DSP, Spartan FPGA + SPM dedicated 8x in and 8x out 16-bit analog at up to 150kHz and digital IO module, two counter/timer channels (preliminary specs.:SR2_Analog_810_UsersManual.pdf)

January 2003: Signal Ranger DSP platform (SR-STD and SR-SP2) -- still full supported but going to be out-dated

The authors were proud to announce that we have managed to get the new 100MHz fixed point TMS320C5402 DSP board, connected via USB to any Linux host, supported by the current GXSM-2 (Gnome-2) SPM software!

GXSM-2.0 and SignalRanger SR-STD/-SP2 DSP board. All SPM functionalities are fully supported by the 4th generation of DSP software design:

  • Digital feedback loop: digital linear with optional two source FUZZY mixing and logarithmic transformation modes usable for AFM/DFM (external PLL) and STM
  • 2D scanning with multi-channel data acquisitation, 2nd scan option (AFM: MFM/EFM like modes) in progress
  • Multi-channel vector probing (STS, I(V), dI/dV using a digital LockIn method)
  • Automatic tip approach (Besocke design, but not limited to this in principle)
  • Coarse motion signal generation (X/Y/Z) for mover type actuators (ala Besocke)

The most recent DSP software (OpenSource, GPL) can be obtained as source or ready to load in binary form (COFF2) via SRanger CVS or from the author! See the Signal Ranger Linux Project for details and read about the current developments!

Introduction and Generic Informations about the GXSM Hardware Interface

GXSM uses a extendable structure of object orientated abstraction classes to support hardware of different types. On top of this the GXSM Hardware Interface Plugins (HwI) now implements the basic set of methods required by the fully abstracted hardware base class defined by Gxsm and thus providing basic SPM control and scan functionality to the whole Gxsm system. Any further more specialized task like, feedback controls, scan speed or spectroscopy has to be implemented by the HwI including the Graphical User Interface (GUI). This allows a maximum of flexibility in supporting any hardware and instrument by just adding HwI for it. Every HwI plugin can be set up to automatically store any additional parameters into the NetCDF data file at the time of data file saving.

The Signal Ranger HwI's (for the old SR and the new SR2-A810) are implemenings the methods to interact with the Signal Ranger DSP subsystem. It is responsible for setting all parameters and data streaming. For the users the controls are presented within one control window, ordered by tasks and separated into folders for feedback and scan control (as shown here).

In addition to standard SPM functions such as setting the bias voltage and IV-spectroscopy, the HwI plugin also provides several advanced functions. For instance, GXSM is able to perform automatic spectroscopic measurements during scanning (raster vector probe) and scan parameters can be changed automatically when passing given positions during scans (trigger function). For sample and tip manipulation, GXSM supports modes for lateral and vertical manipulation of atoms or molecules as well as voltage pulses that can also be used for tip shaping. A full description of available features can be found in the GXSM manual and on the web site. Its open design allows users to add there own custom designed "probe" or "manipulation" tasks simply by adding a new tab to enter the desired boundary conditions from which the DSP vector probe table is generated to set up the custom mode.

No hardware -- Data Visualisation/Analysis only

In case of 'no hardware use' the internal structure is mapped to a dummy object which does some instrument simulation. Basically a mode for data visualisation.

SPM mode: for any STM/AFM/SARLS and similar instuments

GXSM talks to a special DSP-program/interface or anything similar via the HwI plugin abstraction layer as explained above. The DSP program (in case of the SR and SR2-A810) has to be up and running before GXSM starts, as it just communicated with it. Gxsm can (re)start any time, even in the event of GXSM crashes, the DSP still keeps running and the tip/instrument will be just fine. You can restart GXSM and start over. However, you can not continue getting data of an potentially still runnning scan, as the FIFO dats stream is getting broken and data is lost inbetween and it can not re-syncronoize. So just hit the "STOP" button and restart a new scan.

KMDSP-HWI by Marcello Carla

This provides a Linux Kernel-Level DSP or simulation (possible runnign on an RealTime Linux system). The spm2 package provides the control of a Scanning Probe Microscope through one or two common use DAQ boards (SPM2) and a software simulated DSP. This module supports the use of the spm2 package from within the GXSM program.

In case of SPA-LEED

The new SR-A810 provides (similar to the SR with Coolrunner) now two counter channels. This means basic support for any "event/counts" data source is available. The Gate Time can be set for Line-Spectrums or is automatically matched to scan-speed. High precision gate windows are ensured by very fast hardware gating.

Getting some hardware and driver suport

  • Soft dB, SR2-A810, SignalRanger-SP2 or STD DSP board.
  • The Signal Ranger Linux support is independent of the GXSM project itself, please go here: Signal Ranger Linux Project The SPM-DSP software source is also provided via this project!
  • ----- Archive Info's only below -----

    In case of my Astro CCD

    (Note: very old and experimental) My small astro CCD camera (TC211), published by the c't magazine in the 90s, is controlled via the PC style parport using a special kernel module "ccd.o". The CCD plugin is used to set the exposure time.

    (Archive info only, OLD!) SR-STD/-SP2 DSP platform -- still good support

    GXSM-2.0 and SignalRanger-STD or SP2 DSP board from Soft dB. All basic SPM functionalities are supported by the complete new DSP software design (which is now the 4th DSP software generation of the project history!) as there are:

    • Digital feedback, including digital logarithmic transformation
    • 2D scanning with multi-channel data acquisitation
    • Multi-channel vector probing (STS, I(V), dI/dV using a digital LockIn method)
    • Automatic tip approach (Besocke design, but not limited to this in principle)
    • Coarse motion signal generation (X/Y/Z) for mover type actuators (ala Besocke)

    See also Signal Ranger Linux Project for details and read about the current developments at the discussion forum!

    You need additonally for PC31/PCI32 (not any longer recommended, old kernels only, ...):

    The GXSM Project includes the kernel modules (linux kernel >2.2.x needed!), the DSP program launcher (COFF-loader), a DSP monitoring tool "lcd" and a simple oscilloscope frontend "goszi" for testing:

    • the kernel module pc31.o or pci32.o
    • the DSP loader
    • the DSP monitor, "lcd" (older xforms version) or "dsp_applet"
    • the Goszi (libgpib needed), a simple Software oscilloscope Tool - but I recommend you to have a fine analog or even digital scope too.
    • GBM Hompage, DSP-Cards: GBM, Germany
    • USA site: Innovative, USA

    Internet device for RHK type electronics and more

    Extra and/or special documentations supplied by GXSM users can be viewed (and also new documents can be supplied) via the SourceForge hosted GXSM Documentation Manager.

    (Archive info only, OLD!) Supported DSP Cards -- may not work out-of-the box, outdated

    The GXSM Project supports two versions of (old) DSP-Cards from GBM/Innovative.

    The hardware is supported via a device "/dev/pcdsp" and the matching kernel module "pc31.o" or "pci32.o", which is used by GXSM in the same way for both cards. In the other way round, the device is independent of the program running on the DSP, because of the flexible command like comunication. This means, that different tasks on the DSP can be initiated from GXSM via the generalized device. Which is used to run SPA-LEED...

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