Hi,

Thanks Peter for your great explanation.
 
> 7816-3:1997 section 8.2 on work waiting time:
>
> wwt = 960 * WI * (Fi / f)
>

This is exactly what I get doning variable
substitution and symplification in the formula that
comes in ISO 7816-3: 1992.

[snip]

> It seems, therefore, that changing the value of Di
> in the ATR does not
> change the value of the wwt, but changing the value
> of Fi does. Is this what
> the writers of 7816-3:1997 meant? I don't think so,
> because the wwt required
> is related to the values of clock sent to the card,
> the internal structure
> of the card's CPU and clock processing circuits, and
> the application
> algorithm programmed into the card. Changing Fi and
> Di doesn't change the
> way that the card runs its application code, and so
> should not change the
> wwt - but changing Fi does change the wwt.
>
> FI from the card, besides influencing I/O bit rate,
> also indicates the max
> clock frequency that the card can be run at. So:
>
> FI = 0 (means Fi = 372), Di = 1 gives a bit rate of
> 9600 in our example, a
> wwt of 1 sec, and indicates (Table 7) a max clock
> frequency of 4 MHz
> (typical for a card run at 3 Volts Vcc)
>
> FI = 1 (also means Fi = 372), Di = 1 gives a bit
> rate of 9600 in our
> example, a wwt of 1 sec, and indicates (Table 7) a
> max clock frequency of 5
> MHz (typical for a low cost card run at 5 Volts Vcc)
>
> FI = 3 (means Fi = 744), Di = 2 also gives a bit
> rate of 9600 in our
> example, but changes the wwt to 2 sec, and indicates
> (Table 7) a max clock
> frequency of 8 MHz (e.g. for a Hitachi 3109 card as
> used by "rollout spec"
> Mondex in a single application environment)
>

But the reader that I'm ussing provides 3.5712 MHz
constant clock rate to the smartcard regardless of the
ATR in the card.

So, must I assume that if the clock rate doesn't
change I must not change the wwt from the standard 1s
value ?

Does this apply to T=1 timeout values, BWT and CWT?

Thanks,
Carlos.

__________________________________________________
Do You Yahoo!?
Get personalized email addresses from Yahoo! Mail - only $35
a year! http://personal.mail.yahoo.com/
***************************************************************
Linux Smart Card Developers - M.U.S.C.L.E.
(Movement for the Use of Smart Cards in a Linux Environment)
http://www.linuxnet.com/smartcard/index.html
***************************************************************

• Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]