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.
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