DS8007 Datasheet, PDF (28/41 Pages) Dallas Semiconductor – Multiprotocol Dual Smart Card Interface

Multiprotocol Dual Smart Card Interface
Activation Sequencing
An activation sequence can only be requested by a
host device through the parallel bus interface. The host
can request an activation sequence for a specific card
(card A or card B) by setting the START bit of the PCRx
register (where x = A or B as determined by the card
select SCx bits of the CSR). The host software can acti-
vate both cards at the same time, but only one card
can be selected to transmit/receive at a given time. The
activation sequence can only occur given satisfactory
operating conditions (e.g., the card is present and the
supply voltage is correct). These conditions can be
ascertained through the HSR, MSR, and CSR bits.
If the microcontroller attempts to write the PCRx.START
bit to 1 without having satisfied the necessary condi-
tions, the card is not activated and the bit does not
change. The activation time (from the assertion of the
START bit until the clock output is enabled) is less than
130µs. The activation sequence is detailed in Figure 9.
ACTIVATION SEQUENCE
1
2
3
4
5
6
START BIT
RSTIN BIT
RSTx
ACTIVATION NEEDS TO OCCUR IN UNDER 130μs
DEACTIVATION SEQUENCE
1
2
3
4
5
6
V_UP
V_CCx
CLKx
I/0x
C4x, C8x
UNDEFINED
VCCx NEEDS TO DECREASE TO LESS THAN 0.4V
TS
T0
ACCORDING TO PCRx.C4, PCRx.C8 BITS
TIMING t0
t1 t2 t3
t4
t5
t_ACT
ACTIVATION SEQUENCE
1. PCRx.START BIT IS SET BY SOFTWARE.
CONDITIONS NEEDED (IN HARDWARE) ARE:
MSR.PRx = 1 (CARD x PRESENT)
HSR.PRTLx, SUPL, PRLx, PTL = 0
2. STEP-UP CONVERTER ACTIVATED (MAY ALREADY BE ON IF ANOTHER CARD WAS ACTIVE).
3. VCCx ENABLED TO 1.8V, 3V, OR 5V AS SELECTED BY PCRx.1V8 AND PCR.3V/5V BITS.
VCCx RISES FROM 0V TO 1.8V, 3V, OR 5V WITH A CONTROLLED RISE TIME OF 0.17V/μs TYPICAL.
4. I/Ox IS PULLED HIGH. C4x, C8x ARE ALSO PULLED HIGH IF PCRx.C4 = 1, PCRx.C8 = 1
(RESPECTIVELY). THESE PINS HAVE INTEGRATED PULLUPS (14kΩ FOR I/Ox AND
10kΩ FOR C4x AND C8x) TO VCCx.
5. CLKx OUTPUT IS ENABLED AND RST OUTPUT IS ENABLED.
(PCRx.RSTIN SHOULD BE "0" FOR ACTIVE-LOW RSTx.)
6. PCRx.RSTIN WRITTEN TO "1" BY SOFTWARE AFTER USING TOC TO TIME SUFFICIENT
DURATION OF RSTx PIN ASSERTION.
t10 t11 t12
t13 t14
t15
t_DE
DEACTIVATION SEQUENCE
1. PCRx.START BIT IS CLEARED BY SOFTWARE.
2. THE ACTIVE-LOW RSTx SIGNAL IS ASSERTED BY SOFTWARE.
3. THE CLKx SIGNAL IS STOPPED.
4. I/Ox, C4x, AND C8x FALL TO 0V.
5. VCCx IS DISABLED AND FALLS TO 0V WITH A TYPICAL RATE OF 0.17V/μs.
6. STEP-UP CONVERTER IS DEACTIVATED IF NOT IN USE BY ANOTHER CARD AND
PINS CLKx, RSTx, I/Ox, AND VCCx BECOME LOW IMPEDANCE TO GROUND.
Figure 9. Card Activation, Deactivation Sequences
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