WO1999062065A1 - Evaluation de donnees binaires a l'aide d'une unite dma - Google Patents

Evaluation de donnees binaires a l'aide d'une unite dma Download PDF

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Publication number
WO1999062065A1
WO1999062065A1 PCT/DE1999/000578 DE9900578W WO9962065A1 WO 1999062065 A1 WO1999062065 A1 WO 1999062065A1 DE 9900578 W DE9900578 W DE 9900578W WO 9962065 A1 WO9962065 A1 WO 9962065A1
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WO
WIPO (PCT)
Prior art keywords
dma unit
count values
unit
counter
stored
Prior art date
Application number
PCT/DE1999/000578
Other languages
German (de)
English (en)
Inventor
Antonius Luettig
Original Assignee
Siemens Nixdorf Retail And Banking Systems Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens Nixdorf Retail And Banking Systems Gmbh filed Critical Siemens Nixdorf Retail And Banking Systems Gmbh
Publication of WO1999062065A1 publication Critical patent/WO1999062065A1/fr

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Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
    • G11B20/10—Digital recording or reproducing
    • G11B20/14—Digital recording or reproducing using self-clocking codes
    • G11B20/1403—Digital recording or reproducing using self-clocking codes characterised by the use of two levels
    • G11B20/1407—Digital recording or reproducing using self-clocking codes characterised by the use of two levels code representation depending on a single bit, i.e. where a one is always represented by a first code symbol while a zero is always represented by a second code symbol
    • G11B20/1419—Digital recording or reproducing using self-clocking codes characterised by the use of two levels code representation depending on a single bit, i.e. where a one is always represented by a first code symbol while a zero is always represented by a second code symbol to or from biphase level coding, i.e. to or from codes where a one is coded as a transition from a high to a low level during the middle of a bit cell and a zero is encoded as a transition from a low to a high level during the middle of a bit cell or vice versa, e.g. split phase code, Manchester code conversion to or from biphase space or mark coding, i.e. to or from codes where there is a transition at the beginning of every bit cell and a one has no second transition and a zero has a second transition one half of a bit period later or vice versa, e.g. double frequency code, FM code
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/08—Methods or arrangements for sensing record carriers, e.g. for reading patterns by means detecting the change of an electrostatic or magnetic field, e.g. by detecting change of capacitance between electrodes

Definitions

  • the invention relates to a device for evaluating information stored in a binary code, this information being stored in the magnetic track of a magnetic memory card in the form of flux changes, with an electromagnetic transducer which emits voltage pulses induced by magnetic flux changes when there is a relative movement between it and the magnetic memory card. wherein the mutual time intervals of the voltage pulses are detected by means of a clock pulse counter and represented in the form of count values, and with a microprocessor system with a central unit for extracting the binary information from the count values stored in a main memory.
  • the invention further relates to a method for evaluating binary information.
  • WO 91/13436 by the same applicant describes various methods for evaluating binary information from a magnetic memory card.
  • digital pulses are formed from the voltage pulses induced by magnetic flux changes and are supplied to the interrupt input of the microprocessor system.
  • the digital impulses then trigger interrupts; these interrupts are further processed in interrupt routines in order to obtain the binary information from the mutual time intervals of the voltage pulses. Since a large number of flux changes are stored on the magnetic track, which leads to a large number of interrupts, the microprocessor system must have a correspondingly fast and complex interrupt processing.
  • the processing of interrupts in interrupt routines has priority. Accordingly, simultaneous processing of data can scarcely take place during the reading of data from the magnetic memory card - the microprocessor system is not used optimally.
  • a DMA unit (DMA stands for Direct Memory Access) is used, in which a certain number of successive data from a start address are stored in cells of the working memory with successive memory addresses.
  • the DMA unit serves to relieve the load on the central unit, since this only initiates the process of directly storing data in the main memory, but is then no longer involved in the storage process itself.
  • a fast data transfer can follow with the help of the DMA unit, since not every data word is requested individually by specifying the memory address.
  • the count value of a free-running clock pulse counter is recorded when an induced voltage pulse occurs.
  • the DMA unit stores the count values of this clock pulse counter in succession in the predetermined area of the main memory. The count values indicate the time intervals of successive flow changes.
  • the time intervals correspond to the spatial distances by which the binary information is determined.
  • the binary information can thus be determined by evaluating the stored count values.
  • the microprocess Sorsystem can have a relatively long interrupt response time in the invention, because the storage of the count values and thus the information contained on the magnetic track is not interrupt-controlled, but detached from the central unit by the DMA unit. Accordingly, complex operating systems for the microprocessor system that have slow interrupt processing can be used.
  • the area in the working memory which is accessed by the DMA unit is divided into two parts.
  • the DMA unit enters the count values in a first part, while at the same time the central unit reads out count values in the other part. In this way, the information stored in the working memory can already be evaluated while the magnetic track is being scanned.
  • the device for evaluating binary information thus works with increased efficiency.
  • a method for evaluating binary information is specified. With this method, the previously described advantageous effects can also be achieved.
  • a read signal denoted by R is fed to an edge detector 10.
  • the read signal is obtained when reading the magnetic track of a magnetic memory card.
  • the binary information in the form of flow changes according to the two-frequency code is stored on this magnetic memory card.
  • binary "1" signals occur when scanning at an approximately constant speed. at twice the frequency of flow changes as with binary "0" signals.
  • the binary information is therefore contained in the distance between two river changes.
  • an electromagnetic transducer (not shown) detects voltage pulses which are caused by the changes in the magnetic flux.
  • the edge detector 10 uses the possibly pre-amplified voltage pulses of the electromagnetic converter to generate digital pulses J, which it supplies on the one hand to the control input of a DMA module 12 and on the other hand to an enable input E of a register 14.
  • the register 14 holds the count value Z of a free-running clock pulse counter 16.
  • This clock pulse counter 16 is driven by clock pulses ⁇ at a clock interval of, for example, one microsecond, as a result of which the temporal resolution is determined.
  • the DMA unit 12 stores the respective count value Z of the clock pulse counter 16 buffered by the register 14 into an area 18 of the main memory.
  • the DMA unit 12 is loaded beforehand with control information by a central unit of a microprocessor system (not shown).
  • This control information contains, inter alia, the start address and the length or the end address of the memory area 18 in which the count values Z are to be stored.
  • the MK 3883 from Mostek or 8089 from Intel can be used as the DMA unit 12.
  • the area 18 of the main memory is divided into two parts 18a and 18b.
  • the central unit first gives the DMA unit 12 the start address Xa for the first memory cell of the first area 18a and its end address dresse Ya or the length of the area.
  • the resulting count values Z are then gradually stored in part 18a with a descending address from Xa to Ya.
  • the DMA unit When the address Ya is reached, the DMA unit generates an interrupt TC1, which is processed by the central processing unit of the microprocessor system.
  • This central unit now transfers the address Xb to the DMA unit 12 as the new start address for the area 18b.
  • the DMA unit 12 then then transfers the count values Z of the clock pulse counter 16 into memory cells with a decreasing memory address of the area 18b.
  • an interrupt TC1 is again generated, whereupon the central unit switches the DMA unit 12 to the first part 18a in order to continue to store count values Z.
  • the incoming count values Z are therefore written into two subareas 18a and 18b which are different from one another.
  • the central unit can access that partial area 18a or 18b that is not currently being written by the DMA unit 12. By simultaneously writing and reading out count values Z, the central unit can already start evaluating binary information while scanning the magnetic memory card.
  • the DMA unit When the count values Z are read into the partial areas 18a, 18b, it can happen that the end of the magnetic track is reached, that is, no further count values are obtained, but the end address Ya, Yb of the respective partial area 18a, 18b has not yet been reached. Without further measures, the DMA unit would not generate an interrupt TC1. In order to avoid this, in one embodiment of the invention the time during which the DMA unit 12 stores count values in the respective partial area 18a, 18b is monitored for exceeding a limit value. When transferring If this limit value is exceeded, the effect of the interrupt TCl is then generated, whereupon the central unit again takes over control for the DMA unit 12 and either ends the scanning process for the magnetic memory card or continues the evaluation of binary information.
  • a DMA unit is expediently used, each of which has an additional register set for the start and end address or maximum length and which, at the same time as the interrupt TCl, TC2, adopts this into the current register set.
  • the microprocessor then has more time in response to the interrupt TCl, TC2 to reset the registers.
  • the time is preferably measured by a clock pulse-controlled counter, to which clock pulses of a predetermined duration are supplied.
  • This counter is released by the DMA unit 12 at the start of the writing of count values and is reset with each pulse of the edge detector 10.
  • the count values are measured for the maximum time between two clock pulses. In comparison to a time monitoring for the signal TCl or TC2, which only started at the beginning of the registration, a faster reaction is thus brought about.

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  • Engineering & Computer Science (AREA)
  • Artificial Intelligence (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Signal Processing (AREA)
  • Signal Processing For Digital Recording And Reproducing (AREA)

Abstract

L'invention concerne un procédé et un dispositif permettant d'évaluer des données binaires sur une carte mémoire magnétique. Les impulsions fournies par un transducteur électromagnétique provoquent le transfert de chacun des états d'un compteur non piloté dans la mémoire d'un système de microprocesseur, par l'intermédiaire d'une unité DMA, indépendamment de l'unité centrale.
PCT/DE1999/000578 1998-05-22 1999-03-04 Evaluation de donnees binaires a l'aide d'une unite dma WO1999062065A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE1998123065 DE19823065A1 (de) 1998-05-22 1998-05-22 Einrichtung und Verfahren zum Auswerten binärer Informationen unter Verwendung einer DMA Einheit
DE19823065.6 1998-05-22

Publications (1)

Publication Number Publication Date
WO1999062065A1 true WO1999062065A1 (fr) 1999-12-02

Family

ID=7868697

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE1999/000578 WO1999062065A1 (fr) 1998-05-22 1999-03-04 Evaluation de donnees binaires a l'aide d'une unite dma

Country Status (2)

Country Link
DE (1) DE19823065A1 (fr)
WO (1) WO1999062065A1 (fr)

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4239151A (en) * 1979-04-19 1980-12-16 International Business Machines Corporation Method and apparatus for reducing the number of rejected documents when reading bar codes
JPS5640946A (en) * 1979-09-12 1981-04-17 Omron Tateisi Electronics Co Reading device of magnetic recording medium
US4626670A (en) * 1983-06-16 1986-12-02 Xico, Inc. Method and system for decoding time-varying, two-frequency, coherent-phase data
US4845348A (en) * 1988-06-20 1989-07-04 Ncr Corporation Method and apparatus for reading bar code magnetic ink characters
FR2635606A1 (fr) * 1988-08-17 1990-02-23 France Etat Procede de lecture d'un code temporel longitudinal et dispositif pour la mise en oeuvre d'un tel procede
WO1991013436A2 (fr) * 1990-03-01 1991-09-05 Siemens Nixdorf Informationssysteme Aktiengesellschaft Procede d'evaluation des informations binaires d'une carte a memoire magnetique
EP0474908A1 (fr) * 1990-09-13 1992-03-18 Siemens Aktiengesellschaft Procédé d'évaluation de bits d'information contenus dans des séquences d'impulsions à codage biphase
JPH06349013A (ja) * 1993-06-01 1994-12-22 Omron Corp 周波数変調信号の２値データ読取り方法

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0670800B2 (ja) * 1989-12-29 1994-09-07 株式会社田村電機製作所 カード読み取り装置
US5687395A (en) * 1994-10-28 1997-11-11 Hewlett-Packard Company Main memory buffer for low cost / high performance input/output of data in a computer system

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4239151A (en) * 1979-04-19 1980-12-16 International Business Machines Corporation Method and apparatus for reducing the number of rejected documents when reading bar codes
JPS5640946A (en) * 1979-09-12 1981-04-17 Omron Tateisi Electronics Co Reading device of magnetic recording medium
US4626670A (en) * 1983-06-16 1986-12-02 Xico, Inc. Method and system for decoding time-varying, two-frequency, coherent-phase data
US4845348A (en) * 1988-06-20 1989-07-04 Ncr Corporation Method and apparatus for reading bar code magnetic ink characters
FR2635606A1 (fr) * 1988-08-17 1990-02-23 France Etat Procede de lecture d'un code temporel longitudinal et dispositif pour la mise en oeuvre d'un tel procede
WO1991013436A2 (fr) * 1990-03-01 1991-09-05 Siemens Nixdorf Informationssysteme Aktiengesellschaft Procede d'evaluation des informations binaires d'une carte a memoire magnetique
EP0474908A1 (fr) * 1990-09-13 1992-03-18 Siemens Aktiengesellschaft Procédé d'évaluation de bits d'information contenus dans des séquences d'impulsions à codage biphase
JPH06349013A (ja) * 1993-06-01 1994-12-22 Omron Corp 周波数変調信号の２値データ読取り方法

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 005, no. 096 (P - 067) 23 June 1981 (1981-06-23) *
PATENT ABSTRACTS OF JAPAN vol. 095, no. 003 28 April 1995 (1995-04-28) *

Also Published As

Publication number Publication date
DE19823065A1 (de) 1999-11-25

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