DS8007A Datasheet, PDF (12/41 Pages) Maxim Integrated Products – Multiprotocol Dual Smart Card Interface

Multiprotocol Dual Smart Card Interface
Pin Description (continued)
PIN
21
22
23
24
25
26
27
28–35
36
NAME
CPA1
CPB1
V_DDA
CPB2
AGND
CPA2
V_DD
D0–D7
RD
FUNCTION
Step-Up Converter Contact 1. Connect a low-ESR capacitor of 220nF between CPA1 and CPA2.
Step-Up Converter Contact 3. Connect a low-ESR capacitor of 220nF between CPB1 and CPB2.
Analog Supply Voltage. Positive analog-supply voltage for the step-up converter; can be higher but not
lower than V_DD. This pin should be decoupled to AGND with a good quality capacitor.
Step-Up Converter Contact 4. Connect a low-ESR capacitor of 220nF between CPB1 and CPB2.
Analog Ground
Step-Up Converter Contact 2. Connect a low-ESR capacitor of 220nF between CPA1 and CPA2.
Digital Supply Voltage. This pin should be decoupled to GND with a good quality capacitor.
8-Bit Digital I/O. This port functions as the data or address/data communication lines between the host
controller and the DS8007A for the nonmultiplexed and multiplexed operating modes, respectively.
Active-Low Parallel Bus Read Strobe Input. In multiplexed mode, this input indicates when the host
processor is reading information from the DS8007A. In nonmultiplexed mode, this pin signals the current
operation is a read (RD = 1) or a write (RD = 0) when CS and WR are low.
37
38
39
40
41
42–45
46, 47
WR
CS
ALE
INT
INTAUX
AD3–AD0
XTAL2,
XTAL1
Active-Low Parallel Bus Write Strobe Input. In multiplexed mode, this input indicates when the host
processor is writing information to the DS8007A. In nonmultiplexed mode, a low on this pin signals the
bus is engaged in a read or write operation.
Active-Low Chip-Select Input. This input indicates when the DS8007A is active on the parallel bus.
Address Latch Enable Input. This signal monitors the ALE signal when the host processor bus is
operating in multiplexed mode. Connect this signal to V_DD when operating in nonmultiplexed mode.
Active-Low Interrupt. This output indicates an interrupt is active.
Auxiliary Interrupt Input. This pin serves as an auxiliary interrupt.
Register Selection Address Inputs. These pins function as the address input lines for the nonmultiplexed
configuration and should be connected to ground or V_DD in the multiplexed configuration.
Crystal Oscillators. Place a crystal with appropriate load capacitors between these pins if that is the
desired clock source. XTAL1 also acts as an input if there is an external clock source in place of a
crystal.
48
DELAY
External Delay Capacitor Connection. Connect a capacitor from this pin to ground to set the power-on
reset delay.
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