DS8007A Datasheet, PDF (33/41 Pages) Maxim Integrated Products – Multiprotocol Dual Smart Card Interface

Multiprotocol Dual Smart Card Interface
CLOCK
PRESCALER
/31: PSC = 0
/32: PSC = 1
PDR
PD7:PD0 =
00h TO FFh
f_CLK
0
2 x f_CLK
1
UCR2x.CKU
RSTx
START BIT
CLR
UCR2x.PSC
CLOCK
PRESCALER
/31: PSC = 0
/32: PSC = 1
(ALIGNED
ETU GENERATOR)
PDR
PD7:PD0 =
00h TO FFh
CLR
GATE
ETU
1
0
SOFTWARE
MODE
ETU
0.5ETU
0.25ETU
EN TOC COUNTERS
CLK
TO3, TO2,
TO1
EN FRACTIONAL ETU
COUNTERS
CLK
10.5 ETU
TO 15 ETU
EN FRAME-ERROR-
DETECTED COUNTER
CLK
10.25 ETU
Figure 11. ETU Generation
Standard Clock Frequencies
and Baud Rates
The DS8007A supports I/O communication and CLKx
frequency generation compliant to the following stan-
dards: ISO 7816, EMV2000, and GSM11-11. Each of
these standards has an allowable CLKx frequency
range and a defined relationship between CLKx fre-
quency and ETU (baud rate) generation that is support-
ed initially and after negotiation.
For ISO 7816, the relationship between ETU (baud rate)
timing and CLKx frequency is as follows:
ETU = (F / D) x (1 / f_CLKX)
The minimum CLKx frequency is fixed at 1MHz. The
default maximum CLKx frequency is 5MHz, however
the maximum CLKx frequency can be increased
according to the Fi parameter given by the card during
ATR. The ISO 7816-1997(3) specification recommends
in Section 4.3.4 that CLKx frequency switches be made
a) immediately after ATR or b) immediately after a suc-
cessful PPS exchange. The transmission parameters F
and D are respectively the clock-rate conversion and
baud-rate adjustment factors. The notations Fd and Dd
are used to represent the ‘d’efault values for these
parameters, which are Fd = 372 and Dd = 1. The nota-
tion Fi and Di are used to represent the values ‘i’ndicat-
ed by the card within the TA(1) character of ATR. If
TA(1) is not present, then Fi,Di are set to the default
Fd,Dd values. The notation Fn and Dn represent values
‘n’egotiated during a successful PPS exchange, which
should be in the range Fd-Fi and Dd-Di, respectively.
During ATR, the default Fd, Dd values shall apply. If the
card comes up in negotiable mode (i.e., TA(2) is
absent from the ATR), then the Fd, Dd parameters con-
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