DS8007A Datasheet, PDF (13/41 Pages) Maxim Integrated Products – Multiprotocol Dual Smart Card Interface

Multiprotocol Dual Smart Card Interface
Detailed Description
The following describes the major functional features of
the device. Use of this document requires the reader
have a basic understanding of ISO 7816 terminology.
Parallel Bus Interface
The device interfaces to a host computer/processor
through a multiplexed or demultiplexed, parallel, 8-bit
data bus (D0–D7). The parallel bus interface monitors
the ALE signal and automatically detects whether a
multiplexed or nonmultiplexed external bus interface is
intended. The nonmultiplexed external bus interface is
the default configuration and is maintained so long as
no edge (activity) is detected on the ALE pin. Once a
rising edge is detected on the ALE pin, the DS8007A is
placed into the multiplexed mode of operation. Once in
the multiplexed mode of operation, a reset/power cycle
or the deassertion of CS forces the device to the non-
multiplexed mode. Connecting the ALE pin to V_DD or
ground forces the device into nonmultiplexed parallel
bus mode. Figure 7 shows that the bus recognition dic-
tates whether the external address lines (AD3–AD0)
can be used directly or whether the external data lines
(D7–D0) must be latched according to the ALE input
signal. In the multiplexed mode of operation, a new
address is latched irrespective of the state of CS.
GNDB
I/OB
C4B
C8B
PRESB
RSTB
CLKB
VCCB
GNDA
I/OA
C4A
C8A
PRESA
RSTA
CLKA
VCCA
RSTOUT
DELAY
VDD
GND
CPA1
CPA2
CPB1
CPB2
VDDA
AGND
VUP
DS8007A
ANALOG
INTERFACE
ISO
UART
DIGITAL
INTERFACE
POWER-SUPPLY
SUPERVISOR
DC-DC
CONVERTER
CONTROL
SEQUENCERS
TIMEOUT
COUNTER
CLOCK
GENERATION
Figure 6. Block Diagram
INT
CS
INTAUX
I/OAUX
AD0
AD1
AD2
AD3
ALE
RD
WR
D0
D1
D2
D3
D4
D5
D6
D7
XTAL1
XTAL2
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