Abstract:
An integrated semiconductor memory device includes external terminals to which an input signal can be applied to each external terminal, and a register circuit with registers. Each register stores a respective input signal. A programming circuit is also provided with programmable switching units configured such that, in a manner dependent on a respective programming state of the programmable switching units, each respective external terminal can be connected to a respective register of the register circuit. The programming circuit can be programmed by applying unit vectors of programming signals alternately to the external terminals. In this case, the programming signal having a first state is applied in each case to one of the external terminals and the programming signal having a second state is applied to the rest of the external terminals. The integrated semiconductor memory makes it possible for an unknown line scrambling to be resolved internally.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims priority under 35 USC § 119 to German Application No. DE 10 2004 052 589.7, filed on Oct. 29, 2004, and titled “Integrated Semiconductor Memory,” the entire contents of which are hereby incorporated by reference.  
       FIELD OF THE INVENTION  
       [0002]     The invention relates to an integrated semiconductor memory device whose data and address terminals are driven via feed lines.  
       BACKGROUND  
       [0003]     Integrated semiconductor memories, such as DRAM (Dynamic Random Access Memory) semiconductor memories, for example, are arranged on a circuit board, for example a motherboard of a computer, and are driven by a memory controller for the purpose of storing or reading out information items. In this case, the output terminals of the memory controller are generally connected to the address and data terminals of the integrated semiconductor product according to a specified standard, for example the JEDEC (Joint Electronic Device Engineering Council) standard. However, the situation arises where it is necessary to deviate from such specified standards for layout reasons.  
         [0004]      FIG. 1  shows a memory module including three integrated semiconductor memories  100 ,  200  and  300 , the data terminals  1 ′,  2 ′,  3 ′ and  4 ′ of which are driven in each case by a memory controller  400 . In this case, the memory controller  400  completely shields the memory products  100 ,  200  and  300  from the module-side driving. Consequently, for an access to memory cells of the memory products, the latter cannot be driven directly externally, but rather only via the memory controller  400  connected upstream. For this purpose, the latter is driven in a manner dependent on a read or write access at a control terminal S, at an address terminal A and in the case of a write access at a data terminal D by data. The memory controller  400  then drives the memory products connected to it via feed lines by means of a standard access protocol.  
         [0005]     For the sake of simplicity, in  FIG. 1  only data terminals of the data controller are connected to data terminals of the semiconductor products via the feed lines. The driving of control and address terminals of memory products by the memory controller is not illustrated. For driving the three memory products, the memory controller  400  has a total of twelve data terminals arranged in three identical groups. Each of the three groups of data terminals includes the data terminals  1 ,  2 ,  3  and  4 . According to the standard specified in the example of  FIG. 1 , the data terminals of the memory controller  400  are intended to be linearly connected in each case to the data terminals of the individual integrated semiconductor memories. This means that the data terminals  1  of the memory controller  400  are intended to be connected to a respective one of the data terminals  1 ′ of the semiconductor products. Correspondingly, a respective one of the data terminals  2  of the memory controller is intended to be connected to a respective one of the data terminals  2 ′ of the semiconductor memories, a respective one of the data terminals  3  of the memory controller is intended to be connected to a respective one of the data terminals  3 ′ of the memory products and a respective one of the data terminals  4  of the memory controller is intended to be connected to a respective one of the data terminals  4 ′ of the semiconductor memories. For reasons of an efficient layout, however, the data terminals of the semiconductor memory  300  are driven in interchanged fashion by the memory controller  400  in the example of  FIG. 1 . By way of example, one of the data terminals  1  of the memory controller  400 , instead of being connected to the data terminal  1 ′ of the memory product  300 , is connected to the data terminal  2 ′ thereof. Correspondingly, one of the data terminals  2  of the memory controller  400 , instead of being connected to the data terminal  2 ′ of the memory product  300 , is connected to the data terminal  1 ′ of the semiconductor memory  300 . Likewise, in comparison with the wiring of the memory products  100  and  200  with the memory controller  400 , the data terminals  3 ′ and  4 ′ of the memory product  300  are also driven in interchanged fashion by the memory controller  400 .  
         [0006]      FIG. 2  shows an enlarged illustration of one of the three groups of data terminals  1 ,  2 ,  3  and  4  of the memory controller  400 , which are connected to the data terminals  1 ′,  2 ′,  3 ′ and  4 ′ of the memory product  300  via lines L on a circuit board. The actual memory chip  30  is situated within the housing of the memory product  300 . The contacts of the memory chip  30  to the outside world, the so-called pads PD, are connected via bonding wires B to the data terminals, the so-called pins of the memory product  300 . Each pad of the memory chip  30  is connected to a register  1 ″,  2 ″,  3 ″ and  4 ″ of a register circuit R on the memory chip. If data signals are transmitted from the memory controller to the memory cell array via the pads, then said signals are buffer-stored in the register circuit R and from there stored in the memory cells SZ of a memory cell array SZF arranged on the semiconductor memory. The memory cells SZ of the memory cell array are generally arranged along word lines WL and bit lines BL. In the case of DRAM memory cells, a memory cell comprises a storage capacitor SC, which can be connected to a connected bit line BL via a selection transistor AT.  
         [0007]     The meaning of the individual pins  1 ′,  2 ′,  3 ′ and  4 ′ is given by the product pad definition. In the case of standard-conforming wiring, the information present at the pin  1 ′ is stored via the pad connected to the bonding wire in the register  1 ″ of the memory product. Likewise, the information items present at the pins  2 ′,  3 ′ and  4 ′ are stored within the product via the corresponding pads in the registers  2 ″,  3 ″ and  4 ″.  
         [0008]     In addition to a standard-deviating interchange of data lines between the memory controller and a connected memory product, however, interchanges may also occur among the address lines between the memory controller and the memory products.  
         [0009]     If the memory product has been tested as free of defects, however, and the interchange or deviation from a standard with regard to the wiring of data and/or address lines, so-called scrambling, between the memory controller and the memory product is known, the scrambling of the data and/or address terminals does not significantly influence the functioning of the products. In this case, on one memory chip, by way of example, a programmable logic circuit is arranged between the pads and further circuit components of the memory chip which are driven by signals applied to the pads.  
         [0010]     U.S. Pat. No. 6,665,782 describes a circuit group including a transmitting unit, for example a camera, and a receiving unit, for example a memory unit for storing digital photographs from the camera. In order to prevent unauthorized users from exchanging data between the transmitting and receiving units, terminals of the camera chip within the transmitting unit are connected via a programmable logic circuit to external output terminals of the transmitting unit. External input terminals of the receiving unit are thus driven with interchanged signals by the transmitting unit. In order to reverse the scrambling within the receiving unit, a further programmable logic circuit is situated between the external input terminals of the receiving unit and terminals of the memory chip of the receiving unit. If the scrambling scheme used in the transmitting unit is known, the programmable logic circuit of the receiving unit can be programmed complementarily with respect to the programmable logic circuit of the transmitting unit in order to resolve the scrambling.  
         [0011]     On the other hand, scrambling of data and/or address lines on a memory module becomes problematic and time-consuming, however, when testing the individual memory products on the module. After soldering on the memory products and wiring with the memory controller, the products generally have to be tested anew, since it is not possible to rule out degradation of memory cells within the memory products by the stress in the course of being soldered onto the module circuit board. In order to discover specific defect mechanisms, characteristic data or voltage topologies are written to the memory cell arrays.  
         [0012]     If the data topologies are generated within a tester, the actual test program is adapted to the respective module circuit board depending on scrambling of the data and/or address terminals on the module. Depending on the module type, it is thus possible to predefine an adapted line scrambling which is drawn up and maintained for the test run. Furthermore, modern test systems have a logical data scrambler which, in address-dependent fashion, chooses the polarity of the information to be written.  
         [0013]     Since the test programs have to be repeatedly rewritten depending on the scrambling used on the circuit board, the method is very time-consuming. If each memory product on a module is wired differently with the memory controller, a dedicated test program has to be used for each memory product and the same test has to be repeated multiply on a module depending on the number of memory products present. The associated outlay for ensuring a high test severity results in increased test costs. If, on the other hand, the individual adaptation of the test programs depending on the line scrambling used on a module test circuit board is dispensed with, individual memory products cannot be tested at all. The consequence is a deficient or not adapted and deterministic test severity.  
         [0014]     In addition to the generation of data topologies within a tester, memory modules often also have special circuits, so-called module self-test engines, which can generate corresponding data topologies for testing. On account of the simple and space-saving construction of these circuits, however, the test engines are usually unable to resolve the scrambling. In this case, products whose data and/or address line wiring between the corresponding terminals of the memory controller and of the semiconductor product deviates from the predefined standard cannot be tested at all or can only be tested inadequately.  
         [0015]     The document DE 101 31 277 A1 describes a semiconductor memory device having an address decoder device. In an address-decoded operating mode, an applied physical address specifying a physical position of a memory cell in a memory cell array is decoded into an electrical address of the memory cell to be addressed. If physical and electrical address diverge in the case of the semiconductor memory device, then an external test system can directly input the physical address of the memory cell to be addressed into an address input device of the semiconductor memory device. The “address scrambling” is thus effected directly by the address decoder device on the semiconductor memory device. In addition to the address decoder device, a data decoder device may also be provided on the semiconductor memory device. In a similar manner to the “address scrambling”, in a data-decoded operating mode, said data decoder device performs a “data scrambling” if “normal” memory cells, in which a logic “0” is stored for example by means of a negatively charged state and “inverted” memory cells, in which a logic “0” is stored for example by means of a positively charged state, are present.  
       SUMMARY OF THE INVENTION  
       [0016]     An object of the present invention is to provide an integrated semiconductor memory device in which signals which drive terminals of the integrated semiconductor memory in a manner that deviates from a definition are fed to a circuit component of the integrated semiconductor memory in a manner corresponding to the definition.  
         [0017]     Another object of the present invention is to provide a method in which signals which drive terminals of an integrated semiconductor memory in a manner that deviates from a definition are fed to a circuit component of the integrated semiconductor memory in a manner corresponding to the definition.  
         [0018]     The aforesaid objects are achieved individually and/or in combination, and it is not intended that the present invention be construed as requiring two or more of the objects to be combined unless expressly required by the claims attached hereto.  
         [0019]     In accordance with the invention, an integrated semiconductor memory comprises external terminals to which an input signal can be applied in each case, a register circuit with registers, where each register is provided to store a respective one of the input signals. The integrated semiconductor memory furthermore comprises a programming circuit with programmable switching units, via which, in a manner dependent on a respective programming state of the programmable switching units, a respective one of the external terminals can be connected to a respective one of the registers of the register circuit. The programming circuit is configured such that the programming state of one of the programmable switching units of the programming circuit is programmed by a respective programming signal being applied to the external terminals the programming signal applied to one of the external terminals having a first state and the programming signals respectively applied to the other of the external terminals having a second state.  
         [0020]     An integrated semiconductor memory designed in this way makes it possible to feed input signals according to a definition, for example a JEDEC standard, to registers of the integrated semiconductor memory independently of the order in which the input signals are fed to the external terminals of the integrated semiconductor memory. The programming circuit ensures that input signals which are applied to the external terminals of the integrated semiconductor memory by a tester, for example, are fed to the registers of the register circuit in accordance with the definition as defined, even if the external terminals are driven by the input signals in a manner counter to the definition, that is to say counter to a predefined standard. Consequently, a test system need not be reprogrammed in wiring-specific fashion for storing a data topology. On the output side, the tester generates at its data and/or address terminals data and/or address vectors which merely need to be adapted to the defect mechanism to be tested. Consequently, a reprogramming of the data and/or address vectors depending on the wiring of the semiconductor memory is not necessary.  
         [0021]     The programming circuit, which is connected between the external terminals of the integrated semiconductor memory and the registers of the register circuit, can be programmed in a simple manner for resolving the line scrambling. For this purpose, the programming signal having a first level is applied to a respective one of the external terminals and the programming signal having a second level is applied to the other programming terminals. Consequently, the interchange scheme with which the external terminals are driven by a transmitting unit, for example a tester or else a memory controller, does not need to be known for the memory-internal resolution of the line scrambling.  
         [0022]     In accordance with one embodiment of the integrated semiconductor memory device of the invention, the programming circuit includes a plurality of input terminals and a plurality of output terminals. A respective one of the external terminals can be connected to a respective one of the input terminals of the programming circuit. Furthermore, a respective one of the output terminals of the programming circuit can be connected to a respective one of the registers of the register circuit. A respective one of the input terminals of the programming circuit can be connected to a respective one of the output terminals of the programming circuit.  
         [0023]     In another embodiment of the integrated semiconductor memory device of the invention, first controllable switches and second controllable switches are provided. A respective one of the external terminals can be connected to a respective one of the input terminals of the programming circuit via a respective one of the first controllable switches. A respective one of the output terminals of the programming circuit can be connected to a respective one of the registers of the register circuit via a respective one of the controllable switches.  
         [0024]     The programmable switching units in each case can include a controllable switch, via which one of the input terminals of the programming circuit can be connected to one of the output terminals of the programming circuit.  
         [0025]     In accordance with one embodiment of the integrated semiconductor memory device of the invention, the programmable switching units are connected to a terminal for application of a control voltage. The programmable switching units in each case have a further controllable switch. The control voltage can be fed via the respective further controllable switch of the programmable switching units to a respective control terminal of the controllable switch of the programmable switching units.  
         [0026]     In another embodiment of the integrated semiconductor memory device of the invention, the programmable switching units in each case contain a programmable element. The respective programmable element of the programmable switching units is connected, on the output side, to a respective control terminal of the further controllable switch of the programmable switching units.  
         [0027]     In accordance with a further embodiment of the integrated semiconductor memory device of the invention, the respective programmable element of the programmable switching unit is further configured such that, in the programmed state, it controls the respective further controllable switch of the programmable switching units into the on state, so that the control voltage is fed to the respective control terminal of the controllable switch of the programmable switching units and controls the respective controllable switch of the programmable switching units into the on state. The respective programmable element of the programmable switching units is further configured such that, in the non-programmed state, it turns off the respective further controllable switch of the programmable switching units, so that the control voltage is isolated from the respective control terminal of the controllable switch of the programmable switching units and the respective controllable switch of the programmable switching units is thus turned off.  
         [0028]     The programmable elements can be formed in each case as fuse elements. The programmable elements are preferably formed in each case as a bistable multivibrator.  
         [0029]     In accordance with one embodiment of the integrated semiconductor memory device of the invention, the bistable multivibrators are arranged in rows and columns. The bistable multivibrators of a row are connected up as shift registers.  
         [0030]     In one preferred embodiment, the integrated semiconductor memory device includes third controllable switches. A respective one of the shift registers can be connected, on the input side, to a respective one of the registers of the register circuit via a respective one of the third controllable switches.  
         [0031]     The integrated semiconductor memory preferably includes fourth controllable switches. A respective one of the external terminals can be connected to a respective one of the registers of the register circuit via a respective one of the fourth controllable switches.  
         [0032]     For programming the programming circuit, the third and fourth controllable switches are controlled into the on state. The programming circuit is subsequently programmed by unit vectors of programming signals being applied alternately to the external terminals. In this case, the programming signal having a first state is applied in each case to one of the external terminals and the programming signal having a second state is applied to the rest of the external terminals. The method is repeated until the first programming state has been applied once to each of the external terminals. The programming circuit is then programmed and makes it possible for an unknown line scrambling to be resolved internally. For this purpose, the third and fourth controllable switches are turned off again and instead the first and second controllable switches are controlled into the on state, so that the external terminals are connected to the registers of the register circuit via the programmable switching units of the programming circuit. In this case, a programmed switching unit connects an external terminal to one of the registers of the register circuit. Signals that are applied to the external terminals are buffer-stored in the register circuit before they are forwarded from there to further circuit components of the integrated semiconductor memory.  
         [0033]     The external terminals can be in each case formed as address terminals or as data terminals.  
         [0034]     A method for operating an integrated semiconductor memory device in accordance with the invention comprises providing an integrated semiconductor memory device including external terminals to which an input signal can be applied in each case, a register circuit with registers, a respective one of the registers being provided for storing a respective one of the input signals, a programming circuit with programmable switching units, via which, in a manner dependent on a respective programming state of the programmable switching units, a respective one of the external terminals can be connected to a respective one of the registers of the register circuit. The programming circuit is configured such that the programming state of one of the programmable switching units of the programming circuit is programmed by a respective programming signal being applied to the external terminals, the programming signal applied to one of the external terminals having a first state and the programming signals respectively applied to the other of the external terminals having a second state. The method involves programming a number of programmable switching units, which corresponds to the number of external terminals, by carrying out a programming step. In this programming step, the programming signal having a first state is applied to one of the external terminals and the programming signal having a second state is applied to the rest of the external terminals. The programming step specified is repeated, in which, upon each repetition of the programming step, the programming signal having the first state is applied to another of the external terminals and the programming signal having the second state is applied to the rest of the external terminals until the programming signal having the first state has been applied precisely once to each of the external terminals.  
         [0035]     The programming of the programmable switching units is effected in the context of an initialization of the programming circuit. So-called unit data/address vectors are transmitted from the controller side on the feed lines to the data and/or address terminals of the integrated semiconductor memory. A logic “0” is communicated on all the feed lines apart from one. A logic “1” is transmitted, by contrast, on one of the feed lines. The unit vectors are collected in an address register or in a data register in the semi-conductor memory. From the address or data register, the unit vectors are forwarded to the programmable switching units for the stepwise programming thereof. If one of the programmable switching units is driven with a logic “1”, then it is in the programmed state. As a result, each of the external terminals of the programming circuit can be connected to each of the registers of the register circuit in a manner that reverses the interchanged driving of the external terminals.  
         [0036]     In one embodiment, the integrated semiconductor memory device is operable in a first or second operating state. A respective one of the external terminals is connected to one of the registers of the register circuit in the first operating state of the integrated semiconductor memory with bridging of the programming circuit. In the second operating state of the integrated semiconductor memory, a respective one of the external terminals is connected via a respective one of the programmable switching units of the programming circuit to a respective one of the registers of the register circuit.  
         [0037]     The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description of specific embodiments thereof, particularly when taken in conjunction with the accompanying drawings where like numerals designate like components. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0038]      FIG. 1  shows a memory module with different wiring of feed lines to data terminals between a memory controller and semiconductor memory products.  
         [0039]      FIG. 2  shows an enlarged illustration of a memory product whose data lines are driven by a memory controller with a wiring that deviates from a standard.  
         [0040]      FIG. 3  shows a circuit arrangement for carrying out a “rescrambling” according to the invention.  
         [0041]      FIG. 4A  shows an embodiment of a programmable programming circuit according to the invention.  
         [0042]      FIG. 4B  shows an embodiment of a programmable switching unit according to the invention.  
         [0043]      FIGS. 5A-5D  show a programming of a programming circuit according to the invention. 
     
    
     DETAILED DESCRIPTION  
       [0044]      FIG. 3  shows the data terminals  1 ,  2 ,  3  and  4  of the memory controller  400 , which are connected via data lines L to the data terminals  1 ′,  2 ′,  3 ′ and  4 ′ of the memory module  300 . The data pins  1 ′,  2 ′,  3 ′ and  4 ′ are connected via controllable switches  14  to the registers  1 ″,  2 ″,  3 ″ and  4 ″ of the register circuit R. On the output side, the register circuit R is connected to the memory cell array SZF of  FIG. 2 , where the memory cell array is not illustrated in  FIG. 3 . As a result of the scrambling of the lines L, the input signal ES 1  generated at the controller terminal  1  for the memory product is fed to the data pin  2 ′ and, via one of the controllable switches  14 , to the register  2 ″ of the register circuit R. The input signal ES 2  generated at the data output  2  of the memory controller  400  is fed to the data pin  1 ′ and, via one of the controllable switches  14 , to the register  1 ″ of the register circuit R. The input signal ES 3  generated at the controller output is fed to the data pin  4 ′ and, via one of the controllable switches  14 , to the register  4 ″ of the register circuit R. The input signal ES 4  generated at the data output  4  of the memory controller  400  is fed to the data pin  3 ′ and thus to the register  3 ″ of the register circuit R.  
         [0045]     In order to store data in accordance with a data topology in the memory cells of the memory cell array, it is required by way of a standard that the input signal ES 1  be fed to the data terminal  1 ′ and, respectively, to the register  1 ″, the input signal ES 2  be fed to the data terminal  2 ′ and, respectively, to the register  2 ″, the input signal ES 3  be fed to the data terminal  3 ′ and, respectively, to the register  3 ″, and the input signal ES 4  be fed to the data terminal  4 ′ and, respectively, to the register  4 ″. As explained above, the feeding of the input signals ES 1 , . . . , ES 4  deviates, however, from the required feeding to the data terminals  1 ′, . . . ,  4 ′ and, respectively, to the registers  1 ″, . . . ,  4 ″.  
         [0046]     The register circuit R is connected to a programming circuit  15  via a controllable switch  13 . The programming circuit  15  includes programmable switching units P 11 , . . . , P 44  arranged in matrix-type fashion within the programming circuit  15 . The input signal that is buffer-stored in the register  1 ″ can be fed via one of the controllable switches  13  to a programming terminal N 1  and thus to the programmable switching units P 11 , P 21 , P 31  and P 41 . The input signal that is buffer-stored in the register  2 ″ can be fed via one of the controllable switches  13  to a programming terminal N 2  and thus to the programmable switching units P 12 , P 22 , P 32  and P 42 . The input signal that is buffer-stored in the register  3 ″ can be fed via one of the controllable switches  13  to a programming terminal N 3  and thus to the programmable switching units P 13 , P 23 , P 33  and P 43 . The input signal that is buffer-stored in the register  4 ″ can be fed via one of the controllable switches  13  to a programming terminal N 4  and thus to the programmable switching units P 14 , P 24 , P 34  and P 44 .  
         [0047]     The programming circuit  15  has, in addition to the programming terminals N 1 , N 2 , N 3  and N 4 , input terminals E 1 , E 2 , E 3  and E 4 , which can be connected to the data pins  1 ′,  2 ′,  3 ′ and  4 ′ via controllable switches  11 . If the controllable switches  14  are turned off and in contrast the controllable switches  11  are controlled into the on state, then the input signals present at the data pins  1 ′,  2 ′,  3 ′ and  4 ′ are fed via the programmable switching units to output terminals A 1 , A 2 , A 3  and A 4  of the programming circuit  15 . The output terminals A 1 , A 2 , A 3  and A 4  are connected via controllable switches  12  to the registers  1 ″,  2 ″,  3 ″ and  4 ″ of the register circuit R. The input signals can thus be written directly to the registers of the register circuit R via the controllable switches  14  or, with switches  14  controlled into the off state and switches  111  and  12  controlled into the on state, be fed to the registers of the register circuit R via the programmable switching units.  
         [0048]     The programmable switching unit P 11 , in the programmed state, connects the input terminal E 1 , the programmable switching unit P 12 , in the programmed state, connects the input terminal E 2 , the programmable switching unit P 13 , in the programmed state, connects the input terminal E 3  and the programmable switching unit P 14 , in the programmed state, connects the input terminal E 4  to the output terminal A 1  of the programming circuit. The programmable switching unit P 21 , in the programmed state, connects the input terminal E 1 , the programmable switching unit P 22 , in the programmed state, connects the input terminal E 2 , the programmable switching unit P 23 , in the programmed state, connects the input terminal E 3  and the programmable switching unit P 24 , in the programmed state, connects the input terminal E 4  to the output terminal A 2  of the programming circuit. The programmable switching unit P 31 , in the programmed state, connects the input terminal E 1 , the programmable switching unit P 32 , in the programmed state, connects the input terminal E 2 , the programmable switching unit P 33 , in the programmed state, connects the input terminal E 3  and the programmable switching unit P 34 , in the programmed state, connects the input terminal E 4  to the output terminal A 3  of the programming circuit  15 . The programmable switching unit P 41 , in the programmed state, connects the input terminal E 1 , the programmable switching unit P 42 , in the programmed state, connects the input terminal E 2 , the programmable switching unit P 43 , in the programmed state, connects the input terminal E 3  and the programmable switching unit P 44 , in the programmed state, connects the input terminal E 4  to the output terminal A 4  of the programming circuit  15 .  
         [0049]     The programmable switching units P 11 , P 21 , P 31  and P 41  can in each case be programmed by a programming signal at the programming terminal N 1 . The programmable switching units P 12 , P 22 , P 32  and P 42  can in each case be programmed by a programming signal at the programming terminal N 2 . The programmable switching units P 13 , P 23 , P 33  and P 43  can in each case be programmed by a programming signal at the programming terminal N 3 . The programmable switching units P 14 , P 24 , P 34  and P 44  can in each case be programmed by a programming signal at the programming terminal N 4 .  
         [0050]      FIG. 4A  shows the matrix-type arrangement of the programmable switching units P 11 , . . . , P 44  of the programming circuit  15 . The programmable switching units each have programmable switches PS. In a programmed state of the programmable switch PS, the programmable switch in each case connects one of the input terminals E 1 , . . . , E 4  of the programming circuit to one of the output terminals A 1 , . . . , A 4  of the programming circuit. Furthermore, each of the programmable switching units is connected to a terminal AV for application of a voltage potential VPP. The voltage potential VPP is for example a voltage which is also used for driving the word lines of the memory cell array in order to control the selection transistors of the memory cells into the on state.  
         [0051]      FIG. 4B  illustrates the programmable switching unit P 44  with the programmable switch PS in enlarged fashion. The programmable switching unit P 44  furthermore includes a programmable element F, which is designed as a multivibrator in the exemplary embodiment. The set inputs of the multivibrator are connected to the programming terminal N 4 . On the output side, the multivibrator F is connected to a further multivibrator within the programmable switching unit P 34 . The multivibrators of the programmable switching units P 44 , P 34 , P 24  and P 14  thus form a shift register SR 4 .  
         [0052]     When the multivibrators of the shift register SR 4  are driven with a clock signal CLK, the state stored in one of the multivibrators of the shift register SR 4  is shifted in the shift register SR 4  by one position into the next multivibrator of the shift register SR 4 . In the same way as the multivibrators that are programmable via the programming terminal N 4 , the multivibrators that are programmable via the programming terminal N 3  also form a shift register SR 3 , the multivibrators that are programmable via the programming terminal N 2  also form a shift register SR 2 , and the multivibrators that are programmable via the programming terminal N 1  also form a shift register SR 1 .  
         [0053]     The programmable switching unit P 44  has an input terminal EP, which is connected to the input terminal E 4 , and an output terminal AP, which is connected to the output terminal A 4  of the programming circuit  15 . The input terminal EP is connected to the output terminal AP of the programmable switching unit via a switching transistor T 1 . A control terminal ST 1  of the switching transistor T 1  is connected via a switching transistor T 2  to the terminal AV for application of the control voltage VPP. A control terminal ST 2  of the switching transistor T 2  is controlled by the multivibrator F on the output side.  
         [0054]     If the programming terminal N 4  is driven with a high level of a programming signal, the multivibrator F is set with a state “1”. Upon the next clock signal CLK, the state “1” is advanced into the programmable switching unit P 34 . For this purpose, the multivibrator F generates on the output side a high signal level that controls the switching transistor T 2  into the on state, so that the control terminal ST 1  of the switching transistor T 1  is driven by the control voltage VPP. The control voltage VPP has a high potential level that also controls the switching transistor T 1  into the on state. Consequently, the input terminal E 4  of the programming circuit  15  is connected to the output terminal A 4 .  
         [0055]     The functioning of the programming circuit  15  will be explained in more detail below with reference to  FIGS. 5A, 5B ,  5 C and  5 D. The method can be applied in parallel to the memory products arranged on the memory module. For the sake of simplicity, the method is described below on the basis of the integrated semiconductor memory  300 .  
         [0056]     In order to initialize the programmable switching units of the programming circuit  15 , the memory product  300  is driven by the memory controller  400  with a control signal, for example the mode register set command, which is applied to the address terminals of the semiconductor product in order to set a bit in a mode register of the memory product. A control circuit of the memory product  300  thereupon switches the controllable switches  13  and  14  into the on state, whereas the controllable switches  11  and  12  remain turned off.  
         [0057]     In accordance with  FIG. 5A , the memory controller  400  first generates the input signals ES=(ES 1 , ES 2 , ES 3 , ES 4 )=(1, 0, 0, 0) at its data terminals  1 ,  2 ,  3  and  4 . On account of the line scrambling, the data pins  1 ′,  2 ′,  3 ′ and  4 ′ of the memory product  300  are thus driven by the input signal levels 0, 1, 0, 0. These values are stored in the registers  1 ″,  2 ″,  3 ″ and  4 ″ likewise in the order 0, 1, 0, 0. Via the controllable switches  13  controlled into the on state, the multivibrators within the programmable switching units of the column S 4  are programmed with the programming states (P 41 , P 42 , P 43 , P 44 )=(0, 1, 0, 0). Consequently, only the multivibrator of the programmable switching unit P 42  thus has a programmed state.  
         [0058]     The subsequent step for initializing the programming circuit  15  is illustrated in  FIG. 5B . The memory controller generates an input signal having the level ES=(ES 1 , ES 2 , ES 3 , ES 4 )=(0, 1, 0, 0) at its data terminals. On account of the line scrambling, the data pins  1 ′,  2 ′,  3 ′ and  4 ′ of the memory product  300  are thus driven by the signal levels 1, 0, 0, 0. Accordingly, the registers  1 ″,  2 ″,  3 ″ and  4 ″ of the register circuit R are programmed with the states 1, 0, 0, 0.  
         [0059]     Upon the subsequent clock signal, the states stored in the programmable switching units P 41 , P 42 , P 43  and P 44  are advanced into the column S 3 . The programmable switching units of the column S 3  thus assume the programming states (P 31 , P 32 , P 33 , P 34 )=(0, 1, 0, 0). Via the controllable switches  13 , the programming states (P 41 , P 42 , P 43 , P 44 )=(1, 0, 0, 0) are programmed into the column S 4  of the programming circuit  15 . Consequently, only the programmable element P 41  is in a programmed state.  
         [0060]     In the next initialization step, the memory controller then generates the input signal sequence ES=(ES 1 , ES 2 , ES 3 , ES 4 )=(0, 0, 1, 0) at its data terminals. The data pins  1 ′,  2 ′,  3 ′ and  4 ′ of the semiconductor products  300  are thus driven by the signal levels 0, 0, 0, 1 on account of the line scrambling illustrated in  FIG. 3 . These states are in turn buffer-stored in the same order in the registers of the register circuit by means of the linear connection between the data pins and the registers of the register circuit.  
         [0061]     During the subsequent clock cycle, the states stored in the column S 3  are advanced into the column S 2  and the states stored in the column S 4  up to that point are transferred into the column S 3 . The programmable switching units of the column S 4  of the programming circuit  15  are finally programmed, via the controllable switches  13 , with the programming states (P 41 , P 42 , P 43 , P 44 )=(0, 0, 0, 1) which are buffer-stored in the registers of the register circuit. Consequently, the programmable element P 44  is in a programmed state after the third clock cycle.  
         [0062]     The memory controller  400  subsequently generates the input signal levels (ES 1 , ES 2 , ES 3 , ES 4 )=(0, 0, 0, 1) as input signal sequence at its data terminals  1 ,  2 ,  3  and  4 . On account of the line scrambling, the data pins  1 ′,  2 ′,  3 ′,  4 ′ of the memory product  300  are thus driven by the signals 0, 0, 1, 0 which are buffer-stored in the registers  1 ″,  2 ″,  3 ″ and  4 ″ of the register circuit.  
         [0063]     In the subsequent fourth clock cycle, the programming states stored in the programmable switching units of the columns S 2 , S 3  and S 4  are in turn shifted by one column in each case, so that the programmable switching units of the column S 1  are ultimately programmed with the programming states (P 11 , P 12 , P 13 , P 14 )=(0, 1, 0, 0), the programmable switching units of the column S 2  are programmed with the programming states (P 21 , P 22 , P 23 , P 24 )=(1, 0, 0, 0) and the programmable switching units of the column S 3  are programmed with the programming states (P 31 , P 32 , P 33 , P 34 )=(0, 0, 0, 1). Via the registers  1 ″,  2 ″,  3 ″ and  4 ″ and the controllable switches  13 , the programmable switching units of the column S 4  of the programming circuit  15  are then programmed with the programming states (P 41 , P 42 , P 43 , P 44 )=(0, 0, 1, 0). Consequently, the programming states illustrated in  FIG. 5D  are stored in the programmable switching units or in the multivibrators F of the programmable switching units P 11, . . . , P 44 .  
         [0064]     In the programming circuit  15 , therefore, only the programmable switching units P 12 , P 21 , P 34  and P 43  are in a programmed state. In the programmed state, the switching transistors T 1  and T 2  of the programmable switching units are switched into the on state. Consequently, the input terminal E 2  is connected to the output terminal A 1  via the programmed switching unit P 12 . The input terminal E 1  is connected to the output terminal A 2  via the programmed switching unit P 21 . The input terminal E 4  is connected to the output terminal A 3  via the programmed switching unit P 34 , and the input terminal E 3  is connected to the output terminal A 4  via the programmed switching unit P 43 .  
         [0065]     In a subsequent test operating state of the integrated semiconductor memory, the controllable switches  13  and  14  are turned off and the controllable switches  11  and  12  are controlled into the on state. Consequently, a signal present at the data pin  1 ′ is fed to the register  2 ″, a signal present at the data pin  2 ′ is fed to the register  1 ″, a signal present at the data pin  3 ′ is fed to the register  4 ″, and a signal present at the data pin  4 ′ is fed to the register  3 ″. As a result, the signals generated by the memory controller at its data terminals  1 ,  2 ,  3  and  4  are stored in the registers  1 ″,  2 ″,  3 ″ and  4 ″ of the register circuit R.  
         [0066]     This linear connection of data terminals of the memory controller to the registers of the register circuit is independent of the line scrambling used. Consequently, in a functional test of the memory module, despite different line scrambling, all the memory products  100 ,  200  and  300  are driven by the memory controller  400  with the same signal sequence on the input side. The programming circuit  15  ensures that, independently of the line scrambling used, the signal generated at the data terminal  1  of the memory controller  400  is always stored in the register  1 ″ of the register circuit, the signal generated at the data terminal  2  of the memory controller  400  is stored in the register  2 ″ of the register circuit, the signal generated at the data terminal  3  of the memory controller  400  is stored in the register  3 ″ of the register circuit, and the signal generated at the data terminal  4  of the memory controller is stored in the register  4 ″ of the register circuit of the memory products  100 ,  200  and  300 .  
         [0067]     This means that, for the purpose of individually writing to the memory products a data signal sequence that is identical for all the memory products, the same data topology can be generated at the data terminals  1 ,  2 ,  3  and  4  of the memory controller in the respective memory cell array of the memory products. A register within the memory controller  400  which allocates data signals to the respective data terminals of each group of data terminals thus only needs to be programmed once and is therefore independent of the respective line scrambling of a memory product connected to the memory controller  400 .  
         [0068]     Even though the functioning of the programming circuit  15  for discovering the line scrambling of data lines has been explained with reference to the figures illustrated, it can also be used for discovering the line scrambling of address lines. In both cases, the programming circuit  15  is to be connected between the data/address pins and the downstream register of the memory product.  
         [0069]     The programming circuit  15  is preferably arranged on the semiconductor memory. However, it may also be used within the memory controller or within a tester. In this case, the unit vector signals ES=(1, 0, 0, 0); (0, 1, 0, 0); (0, 0, 1, 0); (0, 0, 0, 1) are generated by the memory products  100 ,  200  and  300 . Programming circuits corresponding to the number of memory products driven are contained on the memory controller or in the tester. As a result, a product-specific rescrambling matrix is stored within the memory controller or the tester.  
         [0070]     While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof. Accordingly, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.  
       LIST OF REFERENCE SYMBOLS  
       [0000]    
       
           1 ,  2 ,  3 ,  4  Data terminals of the memory controller  
           1 ′,  2 ′,  3 ′,  4 ′ Data terminals of the memory product  
           1 ″,  2 ″,  3 ″,  4 ″ Registers of the register circuit  
           100 ,  200 ,  300  Memory product  
           1000  Memory module  
           11 ,  12 ,  13 ,  14  Controllable switches  
           15  Programming circuit  
           30  Memory chip  
           400  Memory controller  
          A Address terminal  
          AT Selection transistor  
          AV Terminal for control voltage  
          B Bonding wire  
          BL Bit line  
          CLK Clock signal  
          D Data terminal  
          ES Input signal  
          F Multivibrator  
          L Conductor track  
          N Programming terminal  
          P Programmable switching unit  
          PD Pad  
          S Control terminal  
          SC Storage capacitor  
          SR Shift register  
          ST Control terminal  
          SZ Memory cell  
          SZF Memory cell array  
          T Switching transistor  
          VPP Control voltage  
          WL Word line