Datasheet

Multiplexed Mode

In the multiplexed mode of operation, the D7–D0 sig-

nals are multiplexed between address and data. The

falling edge of the address latch enable (ALE) signal

from the host microcontroller latches the address

(D3–D0), and the RD and WR strobe input signals are

used to enable a read or write operation, respectively, if

the DS8007 is selected (i.e., CS = 0). See the AC timing

for the multiplexed parallel bus mode found earlier in

this data sheet.

Nomultiplexed Mode

In the nonmultiplexed mode of operation, the address is

always provided on the AD3–AD0 signals, and the data

is always transacted on the D7–D0 signals. The RD input

signal is used as a read/write (R/W) operation select. The

WR and CS input signals serve as active-low enables,

and must be asserted for the read or write operation to

take place. See the AC timing for the nonmultiplexed

parallel bus mode found earlier in this data sheet.

DS8007

Multiprotocol Dual Smart Card Interface

14 ______________________________________________________________________________________

REGISTERS

AD3–AD0

D3–D0

D7–D0

LATCH

ALE

RST

CONTROL

LOGIC

RST

Figure 7. Parallel Bus Interface