ISO7816 (part 1-3) asynchronous smartcard information

http://java.inf.elte.hu/java-1.3/javacard/iso7816.txt

=============================================================================
            ISO7816 (part 1-3) asynchronous smartcard information
=============================================================================
 
 - Contents -
 ------------
 
 I ) Introduction of the ISO7816 standard
 
II ) Summary of the ISO7816 standard
 
    2.1 - ISO7816-1 Standard
 
       2.2.1) Minimal Contact Size
       2.2.2) Pin's position
 
    2.2 - ISO7816-2 Standard
 
       2.2.3) Pin Assignement
       2.2.4) Contact Location
 
    2.3 - ISO7816-3 Standard
 
       2.3.1) Electrical Signals Description:
       2.3.2) Voltage and current values:
       2.3.3) Operating procedure for integrated circuit(s) cards:
       2.3.4) Answer to Reset:
 
-----------------------------------------------------------------------------
 
 I ) Introduction of the ISO7816 standard:
     ====================================
 
II ) Summary of the ISO7816 standard:
     ===============================
 
    The ISO7816 standard are separated in 3 different parts
 
     - ISO7816-1 which define the physical characteristics of the card.
     - ISO7816-2 which define dimension and contact position of the card.
     - ISO7816-3 which define the electical signals and transmission
       protocols.
 
     The following organisations should be contacted for more details:
 
       - CEN (Comit Eurpen de Normalisation)
           rue Brderote 2
           B-1000 Brussels
           Belgium
 
       - ISO (International Standard Institute)
           Case postale 56
           CH-1211 Genve 20
           Switzerland
 
    2.1 - ISO7816-1 Standard
          ------------------
     The ISO7816 Standard define many physical features, but here we are only
     going to describe the more intesting features.
 
   * Ultra violet light :
     Any protection beyond the ambiant UV light level shall be to the
     responsability of the card manufacturer.
 
   * X-rays :
     Exposure of either side of the card to a dose of 0.1 Gy relative to a
     medium-energy X radiation of 70 to 140 Kv (cumulative dose per year)
     shall not cause malfunction of the card.
 
   * Surface profile of the contacts :
     The difference in level between all contacts and the adjacent card
     surface shall be less than 0.1 mm.
 
   * Mecanical strenght (of the card and contact)
 
     The card shall resist damage to its surface and any components contained
     in it and shall remain intact during normal use, storage and handling.
 
     surface (with pins) must not be damaged by a pression caused by a steel
     ball of 1.5 mm diameter on which is applied a strenght of 1.5 N.
 
   * Electrical resistance : All the resistances measured between any two
     points of the pins must not be over 0.5 Ohm, with any current value
     from 50 uA to 300 mA.
 
   * Magnetic field : The chip of the card must not be damaged by a static
     magnetic field of 79500 A.tr/m
 
   * Static electricity : The card must not be damaged by a electrical
     discharge of 1500 V of a 100 pF capacitor trought a 1500 Ohm resistance.
 
   * card maximal bending :
 
                         __________
                 ___,---'          '---,___         ^
            _,--'                          '--,_    |  f
          ,'                                    ',  v
 
     a - large side of the card
           - deformation (f) : 2 cm
           - periodicity : 30 bendings a minute
 
     b - short side of the card
           - deformation (f) : 1 cm
           - periodicity : 30 bendings a minute
 
     Acceptance: The card must work correctly and must not have any
     crackings after 1000 bendings.
 
    2.2 - ISO7816-2 Standard
          ------------------
   2.2.1) Minimal Contact Size :
 
        ,-------------,  ^
        |             |  |
        |             |  | 1.7mm
        |             |  |
        '-------------'  v
        :<----------->:
             2mm
 
   2.2.2) Pin's position :
 
      ,-----------------------------------------------------------------
      |      :  :
      |      :  C
      |      D  :
      |      :  ---- ,----,            ,----,
      |      :       | C8 |            | C4 | -,
      |      ------- '----'            '----'  |
      |              ,----,            ,----,  |
      |              | C7 |            | C3 |  |
      |              '----'            '----'  |
      |              ,----,            ,----,  |  AFNOR position
      |              | C6 |            | C2 |  |
      |              '----'            '----'  |
      |              ,----,            ,----,  |
      |              | C5 |            | C1 | -'
      |              '----'            '----'
      |              ,----,            ,----,
      |              | C1 |            | C5 | -,
      |              '----'            '----'  |
      |              ,----,            ,----,  |
      |              | C2 |            | C6 |  |
      |              '----'            '----'  |  ISO7816 position
      |              ,----,            ,----,  |
      |              | C3 |            | C7 |  |
      |              '----'            '----'  |
      |              ,----,            ,----,  |
      |              | C4 |            | C8 | -'
      |              '----'            '----'
      |                                :    :
      |              A                 :    :
      |<------------------------------>:    :
      |                                     :
      |                  B                  :
      |<----------------------------------->:
      |
 
   2.2.3) Pin Assignement:    C1 : Vcc = 5V        C5 : Gnd
          ---------------     C2 : Reset           C6 : Vpp
                              C3 : Clock           C7 : I/O
                              C4 : RFU             C8 : RFU
 
   2.2.4) Contact Location:
          -----------------
 
   All the sizes are in milimeters
 
       |   A       B       C       D         |   A       B       C       D
   ----+-------------------------------  ----+-------------------------------
    C1 | 10.25   12.25   19.23   20.93    C1 | 17.87   19.87   16.69   18.39
    C2 | 10.25   12.25   21.77   23.47    C2 | 17.87   19.87   14.15   15.85
    C3 | 10.25   12.25   24.31   26.01    C3 | 17.87   19.87   11.61   13.31
    C4 | 10.25   12.25   26.85   28.55    C4 | 17.87   19.87    9.07   10.77
    C5 | 17.87   19.87   19.23   20.93    C5 | 10.25   12.25   16.69   18.39
    C6 | 17.87   19.87   21.77   23.47    C6 | 10.25   12.25   14.15   15.85
    C7 | 17.87   19.87   24.31   26.01    C7 | 10.25   12.25   11.61   13.31
    C8 | 17.87   19.87   28.85   28.55    C8 | 10.25   12.25    9.07   10.77
   ----+-------------------------------  ----+-------------------------------
              ISO7816 location                          AFNOR location
 
   NB: The AFNOR location is transitional, and has been used for
       compatibility reasons with existing magnetic stripe cards.
 
    2.3 - ISO7816-3 Standard
          ------------------
 
   2.3.1) Electrical Signals Description:
          ------------------------------
 
   I/O : Input or Output for serial data to the integrated circuit inside
         the card.
 
   VPP :  Programing voltage input (optional use by the card).
 
   GND : Ground (reference voltage).
 
   CLK : Clocking or timing signal (optional use by the card).
 
   RST : Either used itself (reset signal supplied from the interface device)
         or in combination with an interal reset control circuit (optional
         use by the card). If internal reset is implemented, the voltage
         supply on Vcc is mandatory.
 
   VCC : Power supply input (optional use by the card).
 
   NOTE - The use of the two remaining contacts will be defined in the
          appropriate application standards.
 
   2.3.2) Voltage and current values:
          --------------------------
 
   Abbreviations:
 
     Vih : High level input voltage
     Vil : Low level input voltage
     Vcc : Power supply voltage at VCC
     Vpp : Programming voltage  at VPP
     Voh : High level output voltage
     Vol : Low level output voltage
     tr  : Rise time between 10% and 90% of signal amplitude
     tf  : Fall time between 90% and 10% of signal amplitude
     Iih : High level input current
     Iil : Low level input current
     Icc : Supply current at VCC
     Ipp : Programming current at VPP
     Ioh : High level output current
     Iol : Low level output current
     Cin : Input capacitance
     Cout: Output capacitance
 
   * I/O
 
     This contact is used as input (reception mode) or output (transmission
     mode) for data exchange. Two possible states exist for I/O:
 
     - mark or high state (State Z), if the card and the interface device are
       in reception mode or if the state is imposed by the transmitter.
     - space or low state (State A), if this state is imposed by the
       transmitter.
 
     When the two ends of the line are in reception mode, the line shall be
     maintained in state Z. When the two ends are in non-matced transmit
     mode, the logic state of the line may be indeterminate. During
     operations, the interface device and the card shall not both be in
     transmit mode.
 
        Table 1 - Electrical characteristics of I/O under normal
        -------   operation conditions.
 
     ,--------+--------------------------------+---------+---------+------,
     | Symbol |          Conditions            | Minimum | Maximum | Unit |
     +--------+--------+-----------------------+---------+---------+------+
     |        | Either | Iih max = +/- 500uA   |    2    |    VCC  |   V  |
     |  Vih   |   (1)  +-----------------------+---------+---------+------+
     |        |   or   | Iih max = +/- 50uA    | 0.7 VCC | VCC (3) |   V  |
     +--------+--------+-----------------------+---------+---------+------+
     |  Vil   |          Iil max = 1mA         |    0    |    0.8  |   V  |
     +--------+--------------------------------+---------+---------+------+
     |        | Either | Iol max = +/- 100uA   |   2.4   |    VCC  |   V  |
     |  Voh   |        +-----------------------+---------+---------+------+
     |    (2) |   or   | Iol max = +/- 20uA    |   3.8   |    VCC  |   V  |
     +--------+--------+-----------------------+---------+---------+------+
     |  Vol   |          Iol max = 1mA         |    0    |    0.4  |   V  |
     +--------+--------------------------------+---------+---------+------+
     | tr, tf | Cin = 30pF;   Cout = 30pF      |         |      1  |   us |
     +--------+--------------------------------+---------+---------+------+
     | (1) For the interface device, take into account both conditions.   |
     | (2) It is assumed that a pull up resistor is used in the interface |
     |     device (recommended value 20k Ohm.                             |
     | (3) The voltage on I/O shall remain between 0.3V and VCC+0.3V.     |
     '--------------------------------------------------------------------'
 
   * VPP
 
     This contact may be to supply the voltage required to program or to
     erase the internal non-volatile memory. Two possible states exists for
     VPP: Idle state and active state, as defined in table 2. The idle state
     shall be maintained by the interface device unless the active state is
     required.
 
        Table 2 : Electrical characteristics of VPP under normal
        --------  operation conditions.
 
     ,--------+--------------------------------+---------+---------+------,
     | Symbol |          Conditions            | Minimum | Maximum | Unit |
     +--------+--------------------------------+---------+---------+------+
     |  Vpp   |         Idle State             | 0.95*Vcc| 1.05*Vcc|   V  |
     |  Ipp   |   (programming non active)     |         |   20    |  mA  |
     +--------+--------------------------------+---------+---------+------+
     |  Vpp   |        Active State            | 0.975*P | 1.025*P |   V  |
     |  Ipp   |    (programming the card)      |         |     I   |  mA  |
     +--------+--------------------------------+---------+---------+------+
     | The card provides the interface with the values of P and I         |
     | (default values: P=5 and I=50)                                     |
     '--------------------------------------------------------------------'
 
     Rise of fall time : 200 us maximum. The rate of change of Vpp shall not
     exceed 2V/us.
     The maximum power Vpp*Ipp shall not exceed 1.5W when averaged over any
     period of 1s.
 
   * CLK
 
     The actual frequency, delivered by the interface device on CLK, is
     designated either by fi the initial frequency during the answer to
     reset, or by fs the subsequent frequency during subsequent transmission.
 
     Duty cycle for asynchronous operations shall be between 45% and 55% of
     the period during stable operation. Care shall be taken when switching
     frequencies (from fi to fs) to ensure that no pulse is shorter than 45%
     of the shorter period.
 
        Table 3 - Electrical characteristics of CLK under normal
        -------   operation conditions.
 
     ,--------+--------------------------------+---------+---------+------,
     | Symbol |          Conditions            | Minimum | Maximum | Unit |
     +--------+--------+-----------------------+---------+---------+------+
     |        | Either | Iih max = +/- 200uA   |   2.4   | VCC (2) |   V  |
     |        |   (1)  +-----------------------+---------+---------+------+
     |  Vih   |   or   | Iih max = +/- 20uA    | 0.7*VCC | VCC (2) |   V  |
     |        |   (1)  +-----------------------+---------+---------+------+
     |        |   or   | Iih max = +/- 10uA    | VCC-0.7 | VCC (2) |   V  |
     +--------+--------+-----------------------+---------+---------+------+
     |  Vil   |          Iil max = +/-200 uA   |   0 (2) |    0.5  |   V  |
     +--------+--------------------------------+---------+---------+------+
     | tr, tf |          Cin = 30pF            |         |9% of the period|
     |        |                                |         |with a max:0.5us|
     +--------+--------------------------------+---------+---------+------+
     | (1) For the interface device, take into account three conditions.  |
     | (2) The voltage on CLK shall remain between 0.3V and Vcc+0.3V.     |
     '--------------------------------------------------------------------'
 
   * RST
 
        Table 4 - Electrical characteristics of RST under normal
        -------   operation conditions.
 
     ,--------+--------------------------------+---------+---------+------,
     | Symbol |          Conditions            | Minimum | Maximum | Unit |
     +--------+--------+-----------------------+---------+---------+------+
     |        | Either | Iih max = +/- 200uA   |    4    | VCC (2) |   V  |
     |  Vih   |   (1)  +-----------------------+---------+---------+------+
     |        |   or   | Iih max = +/- 10uA    | VCC-0.7 | VCC (2) |   V  |
     +--------+--------+-----------------------+---------+---------+------+
     |  Vil   |          Iil max = +/- 200uA   |   0 (2) |    0.6  |   V  |
     +--------+--------------------------------+---------+---------+------+
     | (1) For the interface device, take into account both conditions.   |
     | (2) The voltage on RST shall remain between 0.3V and VCC+0.3V.     |
     '--------------------------------------------------------------------'
 
   * VCC
 
     This contact is used to supply the power voltage Vcc.
 
        Table 5 - Electrical characteristics of VCC under normal
        -------   operation conditions.
 
              ,--------+---------+---------+-------,
              | Symbol | Minimum | Maximum |  Unit |
              +--------+---------+---------+-------+
              |  Vcc   |   4.75  |   5.25  |   V   |
              |  Icc   |         |    200  |  mA   |
              '--------+---------+---------+-------'
 
   2.3.3) Operating procedure for integrated circuit(s) cards:
          ---------------------------------------------------
   This operating procedure applies to every integrated circuit(s) card with
   contacts:
 
   The dialogue between the interface device and the the card shall be
   conducted through the consecutive operations:
 
      - connection and activation of the contacts by the interface device.
      - reset of the card.
      - answer to reset by the card.
      - subsequent information exchange between the card and the interface
        device.
      - desactivation of the contacts by the interface device.
 
   These operations are specified in the following subclauses.
 
   NOTE : An active state on VPP should not only be provided and maintained
          when requested by the card.
 
   a - Connection and activation of the contacts:
       -----------------------------------------
 
   The electrical circuits shall not be activated until the contacts are
   connected to the interface device so as to avoid possible damage to any
   card meeting these standards.
 
   The activation of the contacts by the interface device shall consist of
   the consecutive operations:
 
       - RST is in state L;
       - VCC shall be powered;
       - I/O in the interface device shall be put in reception mode;
       - VPP shall be raised to idle state;
       - CLK shallbe provided with a suitable and stable clock.
 
   b - Reset of the card:
       -----------------
   A card reset is initiated by the interface device, whereupon the card
   shall respond with an Answer to Reset as describe in 2.4.
 
   By the end of the activation of the contacts (RST is in L, VCC powered and
   stable, I/O in reception mode in the interface device, VPP stable at idle
   level, CLK provided with a suitable and stable clock), the card answering
   asynchronously is ready for reset.
 
   The clock signal is applied to CLK at time T0. The I/O line shall be set
   to state Z within 200 clcok cycles of the clock signal (t2) being applied
   to CLK (time t2 after T0).
 
   An internally reset card reset after a few cycles of clock signal. The
   Answer to Reset on I/O shall begin between 400 and 40 000 clock cycles
   (t1) after the clock signal is applied to CLK (time t1 after T0).
 
   A card with an active low reset is reset by maintaining RST in state L for
   at least 40 000 clock cycles (t3) after the clock signal is applied on CLK
   (time t3 after T0). Thus if no Answer to Reset begind within 40 000 clock
   cycles (t3) with RST in state L, RST is put to state H (at time T1). The
   Answer to Reset on I/O shall begin between 400 and 40 000 clock cycles
   (t1) after the rising edge of the signal on RST (time t1 after T1).
 
   If the Anwser to Reset does not begin within 40 000 clock cycles (t3) with
   RST in state H (t3 after T1), the signal on RST shall be returned to state
   L (at time T2) and the contacts shall be desactivated by the interface
   device.
 
GND ________________________________________________________________________
      __________________________________________________________________
VCC _| :                                                               :|___
       :_______________________________________________________________:
VPP __|:                                                               |____
       :             t3                            t3                  :
       :<--------------------------->:<------------------------------->:
       :                             :_________________________________:
RST ___:_____________________________|                                 |____
       :                             :                                 :
CLK ___|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||____
       :       t1                    :                                 :
       :<-------------->:            :                                 :
       :      __________:____________:_________________________________:
I/O __XXXXXXXX          |____________:_______Answer____________________:XXXX
(IR)   :      :                      :                                 :
       :  t2  :                      :      t1                         :
       :<---->:                      :<---------->:                    :
       :      _______________________:_________________________________:
I/O __XXXXXXXX                       :            |______Answer________:XXXX
(AL)   :  t2  :                      :                                 :
       :<---->:                      :                                 :
       :                             :_________________________________:
I/O __XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX:                                 :XXXXX
(SH)   :                             :                                 :
       T0                            T1                                T2
       IR : Internal Reset                t2 <= 200/fi
  AL : Asynchronous Reset            400/fi <= t1 <= 40000/fi
  SH : Syncronous Reset              40000/fi <= t3
 
                      Figure1 : Reset of the card
                      -------
 
   With a card answering synchonously, the interface device sets all the
   lines to state L (See figure 2). VCC is the powered, VPP is set to idle
   state, CLK and RST remain in L state, I/O is put in reception mode in the
   interface device, RST shall be maintained in state H for at least 50 us
   (t12), before returning to state L again.
 
   The clock pulse is applied after an interval (t10) from the rising edge of
   the reset signal. The duration of the state H of the clock pulse can be
   any value between 10 us and 50 us ; no more than one clock pulse during
   reset high is allowed. The time interval between the falling edges on CLK
   and RST is t11.
 
   The first data bit is obtained as an answer to reset on I/O while CLK is
   in state L and is valid after an interval t13 from the falling edge on RST.
 
      ______________________________________________________________________
VCC__/
 
       _____________________________________________________________________
VPP___/
                 t12
         :<---------------->:
         :__________________:
RST_____/:                   \_______________________________________________
         :                    :
         :  t10           t11 :          t15      t16
         :<---->:      :<---->:  t14   :<---->: :<---->:
                : ____ :      :<---->: :______: :      : _______
CLK_____________:/  1 \:______:______:/   2    \:______:/   3   \_______
                              :                 :
                              : t13             :  t17
                              :<---->:          :<---->:
       _____________________________ :______________   :______________   ___
I/O___//////////////////////////////\:_______1______X-X_______2_______X-X___
 
5us  <= t10                          10us <= t14 <= 100us Clock low after RST
5us  <= t11                          10us <= t15 <= 50us  Clock High
50us <= t12 ........ Reset High      10us <= t16 <= 100us Clock Low
t13  <= 10us  Propagation delay      t17 <= 10us  Propagation delay
 
           Figure2 : Reset of the card when a synchronous answer is expected.
           -------
 
   NOTES:
 
   1 -  The internal state of the card is assumed not to be defined before
   reset. Therefore the design of the card has to avoid inproper operation.
 
   2 - In order to continue the dialogue with the card, RST shall be
   maintained in the state where an answer occurs on I/O.
 
   3 - Reset of a card can be initiated by the interface device at its
   discetion at any time.
 
   4 - Interface devices may support one or more of these types of reset
   behaviour. The priority of testing for asynchronous or synchronous cards
   is not defined in this standard.
 
   c - Deactivation of the contacts
       ----------------------------
   When informations exchange is terminated or aborted (unresponsive card or
   detection of card removal), the electrical contacts shall be desactivated.
 
   The deactivation by the interface device shall consist of the consecutive
   operations:
 
       - State L on RST;
       - State L on CLK;
       - Vpp inactive;
       - State A on I/O;
       - VCC inactive;
 
   2.3.4) Answer to Reset:
          ---------------
   Two types of transmissions are considered:
 
   * Asynchronous transmission:
     In this type of transmission, characters are transmitted on the I/O line
     in an asynchronous half duplex mode. Each character includes an 8bit
     byte.
 
   * Synchronous transmission:
     In this type of transmission, a series of bits is transmitted on the I/O
     line in half duplex mode in synchronisation with the clock signal on CLK.
 
   a - Answer to Reset in asynchronous transmission
       --------------------------------------------
 
   * Bit duration
     """"""""""""
     The nominal bit duration used on I/O is defined as one Elementary Time
     Unit (etu).
 
     For cards having internal clock, the initial etu is 1/9600 s.
 
     For cards using the external clock, there is a linear relationship
     between the Elementary Time Unit used on I/O  and the period provided
     by the interface device on CLK.
 
        The initial etu is 372/fi s  where fi is in Hertz.
 
     The initial frequency fi is provided by the interface device on CLK
     during the Answer to Reset.
 
     In order to read the initial character (TS), all cards shall initially
     be operated with fi in the range of 1 MHz to 5 MHz.
 
   * Character frame during answer to reset
     """"""""""""""""""""""""""""""""""""""
     Prior to the transmission of a character, I/O shall be in state Z.
 
     A character consists of ten consecutive bits:
 
        - a start bit in state A;
        - eight bits of information, designated ba to bh and conveying a
          data byte;
        - a tenth bit bi used for even parity checking.
 
     A data byte consists of 8 bits designated b1 to b8, from the least
     significant bit (lsb, b1) to the most significant bit (msb, b8).
 
     Conventions (level coding, connecting levels Z/A to digits 1 or 0: and a
     bit significance, connecting ba...bh to b1...b8) are specified in the
     initial character, call TS, which is transmitted by the card in response
     to reset.
 
     Parity is correct when the number of ONES is even in the sequence from
     ba to bi.
 
     Whithin a character, the time from the leading edge of the start bit to
     the trailing edge of the nth bit shall equal (n+/-0.2) etu.
 
     When searching for a start, the receiver samples I/O periodically. The
     time origin being the mean between last observation of level Z and first
     observation of level A, the start shall be verified before 0.7 etu, and
     then ba is received at (1.5 +/-0.2) etu. Parity is checked on the fly.
 
     NOTE : When searching for a start, the sampling time shall be less than
     0.2 etu so that all the test zones are distinct from the transition
     zones.
 
     The delay between two consecutives characters (between start leading
     edges) is at least 12 etu, including a character duration (10+/-0.2) etu
     plus a guardtime, the interface device and the card reamain both in
     reception, so that I/O is in state Z.
 
            Start                          Parity             Next
             bit <----- 8 data bits -----> bit              Start bit
     Z   ____     ________________________________......______     __
             |   |  |  |  |  |  |  |  |  |  |                 |   |
     I/O     |   |ba|bb|bc|bd|be|bf|bg|bh|bi|     Guardtime   |   |
             |___|__|__|__|__|__|__|__|__|__|                 |___|_
     A       :   :                    :     :
             0   t1                   :    t10
             :                        :
             :<---- (n+/-0.2) etu --->:
 
                          Figure 3: Character frame
                          --------
 
     During the Answer to Reset, the delay between the start leading edges of
     two consecutives characters from the card shall not exeed 9600 etu. This
     maximum is named initial waiting time.
 
   * Error detection and character repetition
     """"""""""""""""""""""""""""""""""""""""
     During the answer to reset, the following characters repetition
     procedure depends on the protocol type. This procedure is mandatory for
     cards using the protocol type T=0; it is optional for the interface
     device and for the other cards.
 
     The transmitter tests I/O (11+/-0.2) etu after the start leading edge:
         - If I/O is in state Z, the correct reception is assumed.
         - If I/O is in state A, the transmission is assumed to have been
           incorrect. The disputed character shall be repeated after a delay
           of at least 2 etu after detection of the error signal.
 
     When parity is incorrect, from (10.5+/-0.2) etu, the receiver transmits
     an error signal at state A for 1 etu minimum and 2 etu maximum.  The
     receiver then shall expect a repetition of the disputed character (see
     figure 8).
 
     If no character repetition is provided by the card,
         - The card ignores and shall not suffer damage from the error signal
           coming from the interface device.
         - The interface device shall be able to initiate the reception and
           the whole Answer to Reset response sequence.
 
   * Structures and content
     """"""""""""""""""""""
     A reset operation results in the answer from the card consisting of the
     initial character TS followed by at most 32 characters in the following
     order:
 
         - T0 ................... Format character     (Mandatory)
         - TAi, TBi, TCi, TDi ... Interface characters  (Optional)
         - T1, T2, ... ,TK ...... Historical characters (Optional)
         - TCK .................. Check character    (Conditional)
 
Reset
 |
 |    _________________________________________         _______   _________
 |   |   |   |   |   |   |   |   |   |   |   |           |   |     |   |   |
 '-->| TS| T0|TA1|TB1|TC1|TD1|TA2|TB2|TC2|TD2| ......... | T1| ... | TK|TCK|
     |___|___|___|___|___|___|___|___|___|___|_         _|___|_   _|__ |___|
 
     TS  : Initial character
     TO  : Format character
     TAi : Interface character [ codes FI,DI ]
     TBi : Interface character [ codes II,PI1 ]
     TCi : Interface character [ codes N ]
     TDi : Interface character [ codes Yi+1, T ]
     T1, ... , TK : Historical characters (max,15)
     TCK : Check character
 
         Figure 4 : General configuration of the Answer to Reset
         --------
 
     The interface characters specify physical parameters of the integrated
     circuit in the card and logical characteristics of the subsequent
     exchange protocol.
 
     The historical characters designate general information, for exemple,
     the card manufacturer, the chip inserted in the card, the masked ROM
     in the chip, the state of the life of the card. The specification of
     the historical characters falls outside the scope of this part of
     ISO/IEC7816.
 
     For national simplicity, T0, TAi, ... ,TCK will designate the bytes as
     well as the characters in which they are contained.
 
     Structure of TS, the initial character
     --------------------------------------
     The initial character TS provides a bit shynchronisation sequence and
     defines the conventions to code data bytes in all subsequent characters.
     These conventions refer to ISO1177.
 
     I/O is initially in state Z. A bit synchronisation sequence (Z)AZZA is
     defined for the start bit and bits ba bb bc (see figure 5).
 
     The last 3 bits bg bh bi shall be AAZ for checking parity.
 
     NOTE : This allows the interface device to determinate the etu initially
     used by the card. An alternate measurement of etu is a third of the
     delay between the first two falling edges in TS. Transmission and
     reception mechanisms in the card shall be consistent with the alternate
     definition of etu.
 
     The two possible values of TS (ten consecutive bits from start to bi and
     corresponding hexadecimal value) are
 
         - Inverse convention : (Z)ZZAAAAAZ
           where logic level ONE is A, ba is b8 (msb is first), equal to $3F
           when decoded by inverse convention.
 
         - Direct convention  : (Z)ZZAZZZAAZ
           where logic level ONE is Z, ba is b1 (lsb first), equal to $3B
           when decoded by direct convention.
 
                 Start  ba  bb  bc  bd  be  bf  bg  bh  bi
          Z   ____     _______     ___________         ______
                  |   |   |   |   | Z   Z   Z |       |       |   |
               (Z)| A | Z   Z | A |     or    |       | Z  (Z)
          A       |___|       |___|_A___A___A_|___|___|
 
                    Figure 5 : Initial character TS
                    --------
 
     Structure of the subsequent characters in the Answer to Reset
     -------------------------------------------------------------
     The initial character TS is followed by a variable number of subsequent
     characters in the following order: The format character T0 and,
     optionally the interface characters TAi, TBi, TCi, TDi and the
     historical characters  T1, T2, ... , TK and conditionally, the check
     character TCK.
 
     The presence of the interface characters is indicated by a bit map
     technique explained below.
 
     The presence of the historical characters is indicated by the number of
     bytes as specified in the format character defined below.
 
     The presence of the check character TCK depends on the protocol type(s)
     as defined as below.
 
     - Format character T0
       -------------------
     The T0 character contains two parts:
 
         - The most significant half byte (b5, b6, b7, b8) is named Y1 and
           indicates with a logic level ONE the presence of subsequent
           characters TA1, TB1, TC1, TD1 respectively.
 
         - The least significant half byte (b4 to b1) is named K and
           indicates the number (0 to 15) of historical characters.
 
         ,----,----,----,----,----,----,----,----,
         | b8 | b7 | b6 | b5 | b4 | b3 | b2 | b1 |
         '----'----'----'----'----'----'----'----'
         :<------- Y1 ------>:<-------- K ------>:
 
         Y1 : indicator for the presence of the interface characters
                TA1 is transmitted when b5=1
                TB1 is transmitted when b6=1
                TC1 is transmitted when b7=1
                TD1 is transmitted when b8=1
 
         K : number of hitorical characters
 
                    Figure 6 : Informations provided by T0
                    --------
 
     - Interface characters TAi, TBi, TCi, TDi
       ---------------------------------------
 
     TAi, TBi, TCi (i=1, 2, 3, ... ) indicate the protocol parameters.
     TDi indicates the protocol type T and the presence of subsequent
     characters.
 
     Bits b5, b6, b7, b8 of the byte containing Yi (T0 contains Y1; TDi
     contains Yi+1) state whelther character TAi for b5, character TBi for
     b6, character TCi for b7, character TDi for b8 are or are not (depending
     on whether the relevant bit is 1 or 0) transmitted subsequently in this
     order after the character containing  Yi.
 
     When needed, the interface device shall attribute a default value to
     information corresponding to a non transmitted interface character.
 
     When TDi is not transmitted, the default value of Yi+1 is null,
     indicating that no further interface characters TAi+j, TBi+j,
     TCi+j, TDi+j will be transmitted.
 
         ,----,----,----,----,----,----,----,----,
         | b8 | b7 | b6 | b5 | b4 | b3 | b2 | b1 |
         '----'----'----'----'----'----'----'----'
         :<------ Yi+1 ----->:<------- T ------->:
 
         Yi+1 : indicator for the presence of the interface characters
                TAi+1 is transmitted when b5=1
                TBi+1 is transmitted when b6=1
                TCi+1 is transmitted when b7=1
                TDi+1 is transmitted when b8=1
 
         T : Protocol type for subsequent transmission.
 
                    Figure 7 : Informations provided by TDi
                    --------
 
     - Historical characters T1, T2, ... ,TK
       -------------------------------------
 
     When K is not null, the answer to reset is continued by transmitting
     K historical characters T1, T2, ... , TK.
 
     - Check character TCK
       -------------------
 
     The value of TCK shall be such that the exclusive-oring of all bytes
     from T0 to TCK included is null.
 
     The answer to reset is complete 12 etu after the leading edge of the
     last character.
 
     Protocol type T
     ---------------
     The four least significant bits of any interface character TDi indicate
     a protocol type T, specifying rules to be used to process transmission
     protocols. When TDi is not transmitted, T=0 is used.
 
     T=0 is the asynchronous half duplex character transmission protocol.
     T=1 is the asynchronous half duplex block transmission protocol.
     T=2 and T=3 are reserved for future full duplex operations.
     T=4 is reserved for an enhanced asynchronous half duplex character
         transmission protocol.
     T=5 to T=13 are reserved for future use.
     T=14 is reserved for protocols standardized by ISO.
     T=15 is reserved for future extension.
 
     NOTE : If only T=0 is indicated, TCK shall not be sent. In all other
     cases TCK shall be sent.
 
     Specifications of the global interface bytes
     --------------------------------------------
     Among the interface bytes possibly transmitted by the card in answering
     to reset, this subclaus defines only the global interface bytes TA1,
     TB1, TC1, TD1.
 
     These global interface bytes convey information to determine parameters
     which the interface device shall take into account.
 
     - Parameters F, D, I, P, N
       ------------------------
 
     This initial etu is used during answer to reset is replaced by the work
     etu during subsequent transmission. F is the clock rate conversion
     factor and D is the bit rate adjustment factor to determine the work etu
     in subsequent transmissions.
 
     For internal clock cards:
 
        initial etu = 1/9600 s        work etu = (1/D)*(1/9600) s
 
     For external clock cards:
 
        initial etu = 372/fi s        work etu = (1/D)*(F/fs) s
 
     The minimum value of fs shall be 1MHz.
     The maximum value of fs is given by table 6.
 
    I and P define the active state at VPP.
       - Maximum programming current : Ipp = 1mA
       - Programming voltage         : Vpp = P.V
 
     N is an extra guardtime requested by the card. Before receiving the next
     character, the card requires a delay of at least (12+N) etu from the
     start leading edge of the previous character. No extra guardtme is used
     to send characters from the card to the interface device.
 
     The default values of these parameters are:
        F = 372 ;   D = 1 ;  I = 50 ;  P = 5 ;  N = 0
 
     - Integer values in global interface bytes
       ----------------------------------------
 
     The global interface bytes, TA1, TB1, TC1, TB2 code integer values FI,
     DI II, PI1, N, PI2 which are either equal to or used to compute the
     values of the parameters F, D, I, P, N presented above.
 
     TA1 codes FI over the most significant half byte (b8 to b5) and DI over
     the least significant half byte (b4 to b1).
 
     TB1 codes II over the bits b7 and b6, and PI1 over the 5 least
     significant bits b5 to b1. The most significant bit b8 equals to 0.
 
     NOTE : The interface device may ignore the bit b8 of TB1.
 
     TC1 codes N over the eight bits (b8 to b1).
 
     TB2 codes PI2 over the eight bits (b8 to b1).
 
     Table 6: Clock rate conversion factor F
     -------
 
     ----------------------------------------------------------------------
            FI     |     0000      0001  0010  0011  0100  0101  0110  0111
     --------------+-------------------------------------------------------
            F      | Internal clk   372   558   744  1116  1488  1860  RFU
     --------------+-------------------------------------------------------
      fs (max) MHz |      -           5     6     8    12    16    20   -
     ----------------------------------------------------------------------
 
     ---------------------------------------------------------------
            FI     | 1000  1001  1010  1011  1100  1101  1110  1111
     --------------+------------------------------------------------
            F      |  RFU   512   768  1024  1536  2048   RFU  RFU
     --------------+------------------------------------------------
      fs (max) MHz |  -       5   7.5    10    15    20    -    -
     ---------------------------------------------------------------
      RFU : Reserved for Future Use
 
     Table 7: Bit rate afjustment factor D
     -------
 
     -------------------------------------------------------
        DI | 0000  0001  0010  0011  0100  0101  0110  0111
     ------+------------------------------------------------
        D  |  RFU     1     2     4     8    16   RFU   RFU
     -------------------------------------------------------
 
     -------------------------------------------------------
        DI | 1000  1001  1010  1011  1100  1101  1110  1111
     ------+------------------------------------------------
        D  |  RFU   RFU   1/2   1/4   1/8  1/16  1/32  1/64
     -------------------------------------------------------
      RFU : Reserved for Future Use
 
     - Programming voltage factor P
       ----------------------------
 
     PI1 from 5 to 25 gives the value of P in volts. PI1=0 indicates that VPP
     is connected in the card which generates an internal programming voltage
     from VCC. Other values of PI1 are reserved for future use.
 
     When PI2 is present, the indication of PI1 should be ignores. PI2 from
     50 to 250 gives the value of P in 0.1V. Other values of PI2 are reserved
     for future use.
 
     Table 8 : Maximum programming current factor I
     -------
     -------------------------------
      II  |   00    01    10    11
     -----+-------------------------
      I   |   25    50   100   RFU
     -------------------------------
 
     - Extra guardtime N
       -----------------
 
     N codes directly the extra guard time, from 0 to 254 etu. N=255
     indicates that the minimum delay between the start edges of two
     consecutives characters is reduced to 11 etu.
 
   b - Answer to Reset in synchronous transmission
       -------------------------------------------
   * Clock frequency and bit rate
     """"""""""""""""""""""""""""
     There is a linear relationship between the bit rate on the I/O line and
     the clock frequency provided by the clock interface device on CLK.
 
     Any clock frequency between 7kHz and 50kHz may be chosen for the reset
     sequence. A clock frequency of 7kHz corresponds to 7kbit/s, and values
     of the clock frequency up to 50kHz cause corresponding bit rates to be
     transmitted.
 
   * Structure of the header of the Answer to Reset
     """"""""""""""""""""""""""""""""""""""""""""""
     The reset operation results in an answer from the card containing a
     header transmitted from the card to the interface. The header has a
     fixed length of 32 bits and begins with two mandatory fields of 8 bits,
     H1 and H2.
 
     The chronological order of transmission of information bits shall
     correcpond to bit identification b1 to b32 with the least significant
     bit transmitted first. The numerical meaning corresponding to each
     information bit considered in isolation is that of the digit.
 
           - 0 for a unit corresponding to state A (space)
           - 1 for a unit corresponding to state Z (mark)
 
   * Timing of the haeder
     """"""""""""""""""""
     After the reset procedure, the output information is controlled by clock
     pulses. The first clock pulse is applied between 10us and 100us (t14)
     after the falling edge on RST to read the data bits from the card. State
     H of the clock pulses can be varied between 10us and 50us (t15) and
     state L between 10us and 100us (t16).
 
     The first data bit is obtained on I/O while the clock is low and is
     valid 10us (t13) at least after the falling edge on RST. The following
     data bits are valid 10us (t17) at least after the falling edge on CLK.
     Each data bit is valid until the next falling edge the following clock
     pulse on CLK. The data bits can therefore be sampled at the rising edge
     of the following clock pulses.
 
   * Data content of the header
     """"""""""""""""""""""""""
     The header allows a quick determination of whelther the card and the
     interface device are compatible. If there is no compatibility, the
     contacts shall be desactivated.
 
     The first field H1 codes the protocol type. The values of the codes and
     the corresponding protocol type are
 
          Hexadecimal value   protocol type
          -----------------------------------
           00 and ff          not to be used
           01 to FE           each value is assigned
                              by ISO/IEC JTC1/SC17 to
                              one protocol type
 
     The second field H2 codes parameters for the protocol type coded in
     field H1. The values of H2 are to be assigned by ISO/IEC JTC1/SC17.
 
   2.3.5) Protocol type selection (PTS)
          -----------------------------
   If only one protocol type and FI=D=1 (default value of TA1) and N smaller
   than 255 is indicated in the answer to reset. The transmission protocol
   associated to the protocol type may be started immediately after the
   transmission of answer to reset.
 
   If more than one protocol type and/or TA1 parameter values other than the
   default values and/or N equeal to 255 is/are indicated in the answer to
   reset, the card shall know unambiguously, after having sent the answer to
   reset, which protocol type or/and transmission parameter values (FI, D, N)
   will be used. Consequently a selection of the protocol type and/or the
   transmission parameters values shall be specified.
 
   If the card is able to process more than one protocol type and if one of
   those protocol types is indicated as T=0, then the protocol type T=0 shall
   indicated in TD1 as the first offered protocol, and is assumed if no PTS
   is performed.
 
   If a card offers more than one protocol and if the interface device
   supports only one of these protocols which is not T=0 and does not support
   PTS, the interface should reject or reset the card.
 
   2.3.5.a - PTS protocol
             ------------
   Only the interface device is permitted to start a PTS procedure:
 
      - The interface device sends a PTS request to the card.
      - If the card receives a correct PTS request, it answers by sending a
        PTS confirm, if implemented or the initial waiting time will be
        exceeded.
      - After the succesfull exchange of PTS request and PTS confirm, data
        shall be transmitted from the interface device using the selected
        protocol type and/or transmission parameters.
      - If the card receives an erronous PTS request, it will not send a PTS
        confirm.
      - If the initial waiting time is exceeded, the interface device should
        resetor reject the card.
      - If the interface device receives an erroneous PTS confirm, it should
        reset or reject the card.
 
   The parameters for the transmission of the PTS request and PTS confirm
   shall correspond to those used within the Answer to Reset regarding the
   bit rate and the convention detected by TS and possibly modified by TC1.
 
   2.3.5.b - Structure and content of PTS request and PTS confirm
             ----------------------------------------------------
   The PTS request and PTS response each consist of one initial character
   PTSS, followed by a format character PTS0, three optional parameter
   characters PTS1 PTS2 PTS3, and a character check PCK at the last byte.
 
   PTSS identifies the PTS request or PTS confirm and is coded FF.
 
   PTS0 indicates by the bits b5, b6, b7 set to 1 the presence of the
   subsequently sent optional characters PTS1, PTS2, PTS3 respectively. It
   codes over the least significant bits b4 to b1 the selected protocol type
   T as coded in TD bytes. The most significant bit b8 (default b8=0) is
   reserved for future use.
 
   PTS1 codes the parameter values FI and D as coded in TA1. The interface
   device may send PTS1 in order to indicate the selection FI and/or D values
   to the card. If PTS1 is not sent, FI=1 and D=1 are assumed as defaults.
   The card either acknowledges both the FI and D values by echoing PTS1 or
   does not send PTS1 indicating the use of the default values.
 
   PTS2 indicates the support of N=255, when bit b1 is set to 1. Bit b1 set
   to 0 is the default and indicates that the 11 etu period is not used. If
   bit b2 is set to 1, the card shall use an extra guardtime of 12 etu for
   its transmssion of characters to the interface device. Bit b2 set to 0 is
   the default and indicates that no extra guardtime is required. Bit b3 to
   b8 are reserved for future use.
 
   If PTS2 is sent by the interface device and is not echoed by the card, the
   interface device should reject or reset the card.
 
   The coding and use of PTS3 is not defined.
 
   The value of PCK shall be such that the exclusive-oring of all charcters
   from PTSS to PCK included is null.
 
   2.3.6) Protocol type T=0, asynchronous half duplex character transmission
          protocol----------------------------------------------------------
          --------
   This clause defines the structure and processing of commands initiated by
   an interface device for transmission control and for card specific control
   in an asynchronous half duplex character transmission protocol.
 
   This protocol uses the parameters indicated by the answer to reset, unless
   modified by the protocol type selection.
 
   2.3.6.a - Specific interface parameters: the work waiting time
             ----------------------------------------------------
   In an answer to reset, the interface character TC2 codes the integer value
   WI over eight bits b8 to b1. When no TC2 appears in the answer to reset,
   the default value of WI is 10.
 
   The interval between the start leading edge of any character sent by the
   card and the start leading edge of the previous character (sent either by
   the card or by the interface device) shall not exceed 960*OWI work etu.
   This maximum delay is named the work waiting time.
 
   2.3.6.b - Structure and processing of commands
             ------------------------------------
   A command is always initiated by the interface device. It tells the card
   what to do in a 5-byte header, and allow a transfer of data bytes under
   control of procedure bytes sent by the card.
 
   It is assumed that the card and the interface device know a priori the
   direction of data, in order to ditinguish between instructions for
   incoming data transfer (where data enter the card during execution) and
   instructions for outgoing data transfers (where data leave the card during
   execution).
 
without parity error
--------------------
 
        Start                                    Start
   _____    _____________________________________    ___________
        |  |  |  |  Byte i   |  |  |P |          |  |  Byte i+1
        |__|__|__|__|__|__|__|__|__|__| guartime |__|___________
 
                                   Even
with a parity error               parity
-------------------                bit
        Start                                        Start
   _____    ______________________________ Error   __    ___________
        |  |  |  |  Byte i   |  |  |P |  | signal |  |  |  Byte i+1
        |__|__|__|__|__|__|__|__|__|__|  |________|  |__|___________
 
           Figure 8 : Byte transmission diagram
           --------
 
   * Command header sent by the interface device
     """""""""""""""""""""""""""""""""""""""""""
     The interface device transmits a header over five successive bytes
     designated CLA, INS, A1, A2, L.
 
     - CLA is an instruction class. The value FF is reserved for PTS.
 
     - INS is an instruction code in the instruction class. The instruction
       code is valid only if the least significant bit is 0, and the most
       significant half byte is neither 6 nor 9.
 
     - P1, P2 are a reference (e.g. an address) completing the instruction
       code
 
     - P3 codes the number n of data bytes (D1, ... , Dn) which are to be
       transmitted during the command. The direction of movement of these
       data is a function of the instruction. In an outgoing data transfer
       command, P3=0 introduces a 256 byte data transfer from the card. In an
       incoming data transfer command, P3=0 introduces no transfer of data.
 
     All remaining encoding possibilities for the header are specified in
     subsequent parts of ISO7816.
 
     After transmission of such 5 byte header, the interface device waits for
     a procedure byte.
 
   * Procedure bytes sent by the card
     """"""""""""""""""""""""""""""""
     The value of the procedure bytes shall indicate the action requested by
     the interface device. Three types of procedure bytes are specified:
 
     - ACK : (The seven most significant bits in an ACK byte are all equal or
       complementary to those in the INS byte, apart from the values 6x and
       9x) The interface device control VPP state and exchanges data
       depending on ACK values.
 
     - NULL : (=$60) This byte is sent by the card to restart the working
       time, end to anticipate a subsequent procedure byte. It requests no
       further action neither on VPP nor on Data.
 
     - SW1 (= $6x or $9x, expect $60); The interface device maintains or sets
       VPP at idle and waits for a SW2 byte to complete the command.
 
     Any transition of VPP state (active/idle) must occur within the
     guardtime of the procedure byte, or on the work waiting time overflow.
 
     At each procedure byte, the card can proceed with the command by an ACK
     or NULL byte, or show its disaproval by becoming unresponsive, or
     conclude by an end sequence SW1-SW2.
 
  Byte | Value |  Result
  -----+-------+------------------------------------------------------------
       | INS   | VPP is idle. All remaining data bytes are transferred
       |       | subsequently.
       |       |
       | INS+1 | VPP is active. All remaining data bytes are transferred
       |       | subsequently.
  ACK  | ___   |
       | INS   | VPP is idle. Next data byte is transferred subsequently.
       | _____ |
       | INS+1 | VPP is active. Newt data byte is transferred subsequently.
  -----+-------+------------------------------------------------------------
  NULL | $60   | No futher action on VPP. The interface device waits for a
       |       | new procedure byte
  -----+-------+------------------------------------------------------------
  SW1  | SW1   | VPP is idle. The interface device waits for a SW2 byte
 
     Acknoledge bytes
     ----------------
     The ACK bytes are used to control VPP state and data transfer.
 
       - When exclusive-oring the ACK byte with the INS byte gives $00 or
         $FF, the interface device maintains or sets VPP as idle.
 
       - When exclusive-oring the ACK byte with the INS byte gives $01 or
         $FE, the interface device maintains or sets VPP as active.
 
       - When the seven most significant bits in the ACK byte have the same
         value as those in the INS byte, all remaining data bytes (Di, ...,
         Dn) if any remain, are transferred subsequently.
 
       - When the seven most significant bits in the ACK byte are
         complementary to those in the INS byte, only the next data byte
         (Di), if one remains is transferred.
 
     After these actions, the interface device waits for a new procedure.
 
     Null byte (= $60)
     -----------------
     This byte is sent by the card to reset the workwaiting time and to
     anticipate a subsequent procedure byte.
 
     Status bytes (SW1=$6x or $9x, expect $60; SW2 any value)
     --------------------------------------------------------
     The end sequence SW1-SW2 gives the card status at the end of the command.
 
     The normal ending is indicated by SW1-SW2 = $90-$00.
 
     When the most significant half byte SW1 is $6, the meaning of SW1 is
     independant of the application. The following five values are defined:
 
       $6E The card does not support the instruction class.
       $6D The instruction code is not programmed or is invalid.
       $6B The reference is incorrect.
       $67 The length is incorrect.
       $6F No precise diagnostic is given.
 
     Other values are reserved for future use by ISO7816.
     When SW1 is neither $6E nor $6D, the card support the instruction.
     This part of ISO7816 does not interprets neither $9X SW1 bytes, nor SW2
     bytes; Their meaning relates to the application itself.
 
     Supplement (were seen sometimes):
     ---------------------------------
     SW1  SW2  Meaning
 
     62   81   Returned data may be corrupted.
     62   82   The end of the file has been reached before the end of reading.
     62   84   Selected file is not valid.
     65   01   Memory failure. There have been problems in writing or reading
               the EEPROM. Other hardware problems may also bring this error.
     68   00   The request function is not supported by the card.
     6A   00   Bytes P1 and/or P2 are incorrect.
     6A   80   The parameters in the data field are incorrect.
     6A   82   File not found.
     6A   83   Record not found.
     6A   84   There is insufficient memory space in record or file.
     6A   87   The P3 value is not consistent with the P1 and P2 values.
     6A   88   Referenced data not found.
     6C   XX   Incorrect P3 length.