Philips TDA8002C

1999 Oct 12 11

Philips Semiconductors Product speciﬁcation

IC card interface TDA8002C

Logic circuitry

After power-up, the circuit has six possible states of

operation. Figure 9 shows the state diagram.

IDLE MODE

After reset, the circuit enters the idle mode. A minimum

number of functions in the circuit are active while waiting

for the microcontroller to start a session:

•All card contacts are inactive

•I/OUC, AUX1UC and AUX2UC are high-impedance

•Oscillator (XTAL) runs, delivering CLKOUT

•Voltage supervisor is active.

LOW-POWER MODE

When pin MODE goes LOW, the circuit enters the

low-power (sleep) mode. As long as pin MODE is LOW no

activation is possible.

If pin MODE goes LOW in the active mode, a normal

deactivation sequence is performed before entering the

low-power mode. When pin MODE goes HIGH, the circuit

enters the normal operating mode after a delay of at least

6 ms (96 cycles of CLKOUT). During this time the

CLKOUT remains at 16 kHz.

•All card contacts are inactive

•Oscillator (XTAL) does not operate

•The VDD supervisor, ALARM output, card presence

detection and OFF output remain functional

•Internal oscillator is slowed to 32 kHz, providing 16 kHz

on CLKOUT.

ACTIVE MODE

When the activation sequence is completed, the

TDA8002C will be in the active mode. Data is exchanged

between the card and the microcontroller via the I/O lines.

Fig.9 State diagram.

handbook, full pagewidth

MGE735

POWER

OFF

ACTIVE

MODE

LOW-POWER

MODE

IDLE

MODE FAULT

ACTIVATION

DEACTIVATION