EP0968436A2 - Circuit integre et procede pour essayer ledit circuit integre - Google Patents

Circuit integre et procede pour essayer ledit circuit integre

Info

Publication number
EP0968436A2
EP0968436A2 EP98916822A EP98916822A EP0968436A2 EP 0968436 A2 EP0968436 A2 EP 0968436A2 EP 98916822 A EP98916822 A EP 98916822A EP 98916822 A EP98916822 A EP 98916822A EP 0968436 A2 EP0968436 A2 EP 0968436A2
Authority
EP
European Patent Office
Prior art keywords
test
rom
cpu
integrated circuit
ram
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP98916822A
Other languages
German (de)
English (en)
Inventor
Jürgen NOLLES
Hans-Heinrich Viehmann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Infineon Technologies AG
Original Assignee
Siemens AG
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 AG filed Critical Siemens AG
Publication of EP0968436A2 publication Critical patent/EP0968436A2/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F11/00—Error detection; Error correction; Monitoring
    • G06F11/22—Detection or location of defective computer hardware by testing during standby operation or during idle time, e.g. start-up testing
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
    • G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
    • G06K19/067—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
    • G06K19/07—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips

Definitions

  • the first generation of smart cards could essentially only carry out storage functions. Relatively simple logic functions such as comparing numbers or generating pseudo-additional numbers were added later.
  • a microprocessor is increasingly being used which can carry out the complex security, encryption and / or authentication operations .
  • Cryptological methods are also increasingly being used, which require considerable computing effort.
  • the semiconductor chips contained in today's chip cards thus contain complex and complex circuits, which are usually formed with a CPU, a ROM, an EEPROM (or EPROM) and in some cases further modules such as a UART or a co-processor and a bus connecting them .
  • the CPU is usually assigned a RAM, which is usually designed as static RAM. Since static RAMs take up a lot of space, they are usually very small and only have less than one KB of storage capacity. It is also characteristic of smart card products that they only have one or two serial interfaces to the outside world, which means that data transmission is very slow. Since 8-bit parallel processing takes place internally, a series / parallel conversion is necessary, which is software-controlled by means of the accumulator via CPU, which means that this conversion is also very slow. However, since normal data transmission is defined by an ISO standard and only takes place at a few kbits per second, this means normal operation, ie operation not a problem for the user for the intended use as a rechargeable wallet, for example.
  • chip card products contain a test memory which is designed as ROM.
  • the selftest software consists of various test routines that are called up using test vectors. These test vectors can be entered via the IO port. Since the size of the test memory is limited and fluctuates within the different products, it usually does not contain all test routines. Therefore, the remaining test routines must be loaded into the EEPROM and executed from there. This requires several programming and deletion processes, which take much longer compared to the actual test.
  • the test memory which is designed as a ROM, is part of the ROM on the semiconductor chip, which also contains user programs such as the operating system and frequently used subroutines such as EEPROM write and erase programs.
  • the test memory area thus takes up part of the address space of the ROM, so that an erroneous or deliberate and abusive entry into this address area is possible, even if certain measures attempt to prevent access to this address area of the ROM after the tests have been carried out.
  • the previous implementation thus has the disadvantage of being too slow on the one hand, so that the tests take too long and therefore expensive, and on the other hand to allow access to the test routines even after the test, since these are in one ROMs are hard-wired or can possibly remain non-volatile on the chip in an EEPROM.
  • the object of the present invention is therefore to provide a circuit arrangement which allows a quick test and offers high protection against misuse.
  • the object is achieved by an integrated circuit which comprises at least one CPU, a user ROM, a test ROM and a CPU-internal RAM.
  • the address space of the test ROM lies within the address space of the user ROM, a switching means being provided in the manner according to the invention which only allows access to either the user ROM or the test ROM.
  • the switching means can be irreversibly set into a state that only allows access to the user ROM. In this way, the test ROM can be locked after the end of the test phase without the former address space being no longer occupied. There is therefore no gap in the available address area in which blocked memory areas can lie, so that an attacker cannot benefit from this.
  • test ROM only contains a test start program that is absolutely necessary to start a test. This means that the actual test routines are written into an external RAM, ie additional RAM, a so-called X-RAM, from where they are then executed.
  • a method according to the invention is specified in claim 7.
  • Storing the test routine only in an X-RAM has the advantage that the test routines can be deleted after a test by switching off the supply voltage, since the X-RAM is volatile.
  • this shift register can be used to transfer signals that occur during a test to the outside into the test device for monitoring. This makes the test safer and faster. It is advantageous to encrypt these signals before transmission, which can be done advantageously by a linear or non-linear feedback of the shift register, for example by an XOR gate. However, other gate functions are also possible.
  • FIG. 1 shows a block diagram of an integrated circuit according to the invention
  • FIG. 2 is a more detailed circuit diagram of an advantageous embodiment of the invention.
  • a CPU together with its assigned RAM, an additional X-RAM and a non-volatile EEPROM are connected to one another via a bus.
  • a serial input / output port I / O is connected to the accumulator (not shown) contained in the CPU, which is also used for serial / parallel conversion via the bus.
  • a ROM which mainly contains user software, and a test ROM are also via a switching means MUX, which can be a multiplexer connected to the bus.
  • the switching means MUX can be controlled, for example, by the CPU via the input / output port I / O, which is indicated by an arrow St.
  • the ROM or the test ROM can be connected to the bus and addressed via the switching means MUX.
  • the addresses with which the ROM can be addressed are at least partially identical to the addresses with which the test ROM can be addressed. It is therefore not possible to tell from the addresses whether the ROM or the test ROM is addressed.
  • the bus can be irreversibly connected to the ROM via the switching means MUX, so that the test ROM can be completely separated from the bus after the test phase.
  • test routines can be loaded into the X-RAM from outside and executed from there.
  • the writing of the test routines in the X-RAM has the advantage that this process runs much faster on the one hand and is only volatile on the other hand, so that the test routines in the X-RAM can be quickly deleted again, for example by switching off the supply voltage.
  • the switching means MUX is irreversibly brought into a state which makes it impossible to access the test ROM via the bus.
  • FIG. 2 shows an advantageous further development of the integrated circuit according to the invention in somewhat more detail.
  • the input / output gate I / O can be addressed by the CPU via an address decoder using an SFR (Special Function Register) address via the bus, which in turn has parallel connections to the bus. If the input / output gate I / O is controlled via the SFR address, the incoming and outgoing data are sent to and from the bus CPU transported. A serial / parallel or parallel / serial conversion of incoming or outgoing data can take place in the CPU under program control by means of the accumulator.
  • a shift register SR is connected in parallel to this transmission path, by means of which a rapid series / parallel or parallel / series conversion can take place during the test phase.
  • the shift register SR is also addressed and read by the CPU via an SFR address.
  • a corresponding address decoder SFR is provided in the shift register SR.
  • the shift register can also be activated and deactivated by the CPU via this SFR address.
  • a counter Z which counts the clocks Cl with which the information is written into the shift register SR and a signal to the CPU after each word which controls the writing into the X-RAM.
  • a possible sequence of a test proceeds as follows: First, the tester sends a logical "0" to indicate the start of a data transfer. This releases the counter Z. It indicates after 8 clocks that a byte is to be fetched. The CPU can experience this through a special signal, but it is just as possible to set this period using software. In the waiting loop, in which the CPU waited for the start of a transfer, the address counter of the X-RAM was set to its start. After the transfer, the test routine is first called, then the CPU jumps back into the receive queue.
  • This advantageous development serves to increase the test coverage and the earlier detection of defective chips, provided that the defects can be recognized from the observed internal signals.

Landscapes

  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Quality & Reliability (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Microcomputers (AREA)
  • For Increasing The Reliability Of Semiconductor Memories (AREA)
  • Tests Of Electronic Circuits (AREA)
  • Techniques For Improving Reliability Of Storages (AREA)
  • Test And Diagnosis Of Digital Computers (AREA)

Abstract

L'invention concerne un circuit intégré comprenant une unité centrale (CPU) et une mémoire ROM utilisateur, caractérisé par une mémoire ROM d'essai, dont l'espace adresse se trouve à l'intérieur de l'espace adresse de la mémoire ROM utilisateur, par une mémoire RAM placée à l'extérieur de l'unité centrale (CPU), ainsi que par un dispositif de commutation qui permet un accès seulement soit à la mémoire ROM utilisateur, soit à la mémoire ROM d'essai et peut être mis, de façon irréversible, dans un état qui permet seulement un accès à la mémoire ROM utilisateur.
EP98916822A 1997-03-19 1998-03-02 Circuit integre et procede pour essayer ledit circuit integre Withdrawn EP0968436A2 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19711478A DE19711478A1 (de) 1997-03-19 1997-03-19 Integrierte Schaltung und Verfahren zum Testen der integrierten Schaltung
DE19711478 1997-03-19
PCT/DE1998/000608 WO1998041880A2 (fr) 1997-03-19 1998-03-02 Circuit integre et procede pour essayer ledit circuit integre

Publications (1)

Publication Number Publication Date
EP0968436A2 true EP0968436A2 (fr) 2000-01-05

Family

ID=7823916

Family Applications (1)

Application Number Title Priority Date Filing Date
EP98916822A Withdrawn EP0968436A2 (fr) 1997-03-19 1998-03-02 Circuit integre et procede pour essayer ledit circuit integre

Country Status (7)

Country Link
EP (1) EP0968436A2 (fr)
JP (1) JP2001527669A (fr)
KR (1) KR20000076351A (fr)
CN (1) CN1251183A (fr)
BR (1) BR9808381A (fr)
DE (1) DE19711478A1 (fr)
WO (1) WO1998041880A2 (fr)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3198997B2 (ja) 1997-08-28 2001-08-13 日本電気株式会社 マイクロコンピュータ及びそのバーンインテスト方法
EP0992809A1 (fr) 1998-09-28 2000-04-12 Siemens Aktiengesellschaft Circuit avec trajet d'analyse désactivable
DE10101234A1 (de) * 2001-01-11 2002-07-18 Giesecke & Devrient Gmbh Verfahren zum Text eines nichtflüchtigen Speichers und Verwendung eines solchen Verfahrens
DE602004020414D1 (de) 2003-02-24 2009-05-20 St Microelectronics Sa Verfahren und Vorrichtung zur Auswahl der Betriebsart einer Integrierten Schaltung
CN1829127B (zh) * 2006-04-20 2011-06-29 北京星河亮点通信软件有限责任公司 一种基于微内核的通信终端测试仪表控制平台的构建方法
CN102592683B (zh) * 2012-02-23 2014-12-10 苏州华芯微电子股份有限公司 一种芯片测试模式的进入方法及相关装置
CN103021471B (zh) * 2012-12-24 2016-08-03 上海新储集成电路有限公司 一种存储器及其存储方法
US10818374B2 (en) * 2018-10-29 2020-10-27 Texas Instruments Incorporated Testing read-only memory using memory built-in self-test controller

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0758502B2 (ja) * 1988-06-30 1995-06-21 三菱電機株式会社 Ｉｃカード
JP3125070B2 (ja) * 1990-12-14 2001-01-15 三菱電機株式会社 Ｉｃカード
JPH06236447A (ja) * 1993-02-09 1994-08-23 Mitsubishi Electric Corp Ｉｃカード用マイクロコンピュータ

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9841880A2 *

Also Published As

Publication number Publication date
WO1998041880A3 (fr) 1999-01-14
KR20000076351A (ko) 2000-12-26
JP2001527669A (ja) 2001-12-25
WO1998041880A2 (fr) 1998-09-24
DE19711478A1 (de) 1998-10-01
CN1251183A (zh) 2000-04-19
BR9808381A (pt) 2000-05-23

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