TDA8005A Datasheet, PDF (11/36 Pages) NXP Semiconductors – Low-power 3 V/5 V smart card coupler

Philips Semiconductors
Low-power (3 V/5 V) smart card coupler
Preliminary specification
TDA8005A
Clock circuitry
The clock to the microcontroller and the clock to the card
are derived from the main clock signal (XTAL from
2 to 16 MHz, or an external clock signal).
Directly after reset and during power reduction modes the
microcontroller clock frequency f_clk equals ¹â„₈f_INT; f_INT is
always present because it is derived from the internal
oscillator and gives the lowest power consumption.
When required (for card session, serial communication or
anything else) the microcontroller may choose to clock
itself with ¹â„₂f_XTAL, ¹â„₄f_XTAL or ¹â„₂f_INT. All frequency changes
are synchronous, thereby ensuring no hang-up due to
short spikes etc.
Cards clock: the microcontroller may select to send the
card a card clock frequency of ¹â„₂f_XTAL, ¹â„₄f_XTAL, ¹â„₈f_XTAL or
1_{⁄2fINT (≈1.25 MHz), or to stop the clock HIGH or LOW.}
All transitions are synchronous, ensuring correct pulse
length during start or change in accordance with
ISO 7816.
After power on, CLK is set at STOP LOW and f_clk is set at
1_⁄8fINT.
Power-down and sleep modes
The TDA8005A offers a large flexibility for defining power
reduction modes by software. Some configurations are
described below.
In the power-down mode, the microcontroller is in
power-down and the supply and the internal oscillator are
active. The card is not active; this is the smallest power
consumption mode. Any change on P1 ports or on PRES
will wake-up the circuit (for example, a key pressed on the
keyboard, the card inserted or taken off).
In the sleep mode, the card is powered but configured in
the idle or sleep mode. The step-up converter will only be
active when it is necessary to reactivate V_step-up. When the
microcontroller is in power-down mode any change on P1
ports or on PRES will wake up the circuit.
In both power reduction modes the sequencer is active,
allowing automatic emergency deactivation in the event of
card take-off, hardware problems, or supply dropout.
The TDA8005A is set into power-down or sleep mode by
software. There are several ways to return to normal
mode: insertion or extraction of the card, detection of a
change on P1 (which can be a key pressed) or a command
from the system microcontroller. For example, if the
system monitors the clock signal on XTAL1, it may stop
this clock after setting the device into power-down mode
and then wake it up when sending the clock signal again.
In this situation, the internal clock should have been used
before the f_clk.
Peripheral interface
This block allows synchronous serial communication with
the three peripherals (ISO 7816 UART, clock circuitry and
output port extension); see Figs 1 and 5.
handbook, full pagewidth
RESET
P24
P06
P07
P27
P26
P25
P32
DATA STROBE ENABLE REG0 REG1 R/W
INT
PERIPHERAL CONTROL
clock configuration
CC0 CC1 CC2 CC3 CC4 CC5 CC6 CC7
UART configuration
UC0 UC1 UC2 UC3 UC4 UC5 UC6 UC7
UART transmit
UT0 UT1 UT2 UT3 UT4 UT5 UT6 UT7
ports extension
PE0 PE1 PE2 PE3 PE4 PE5 PE6 PE7
UART receive
UR0 UR1 UR2 UR3 UR4 UR5 UR6 UR7
UART status register
US0 US1 US2 US3 US4 US5 US6 US7
MGL334
Fig.5 Peripheral interface diagram.
1998 Mar 20
11