DocID024511 Rev 2

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ST8034HN, ST8034HC

Functional description

1. Deactivation caused by card withdrawal.

2. Deactivation caused by short-circuit on card side.

6.11

Table 13.

6.12

Chip select (ST8034HC only)

The chip select (CS) input pin of the ST8034HC replaces the CLKDIV1 pin and is active

high, meaning normal operation of the device when CS is in logic high state. When the CS

pin goes low, the status of the ST8034HC device is frozen (i.e. status of control inputs

RSTIN, CMDVCC, CLKDIV, VCC_SEL1 and VCC_SEL2 is latched) and the I/OUC,

AUX1UC, and AUX2UC pins on the microcontroller interface go into high impedance mode

output pin also goes into high impedance mode. This allows the microcontroller to share

interface pins among multiple smartcard interfaces connected in parallel. Status and all the

ST8034HC device functions (including the card) are maintained for immediate use when the

CS goes high again. For this reason clock input is not affected by the chip select, the clock

is provided to the ST8034HC device and to the card even when the CS is low.

VCC_SEL1 pin level

VCC_SEL2 pin level

Low

1. x = “don't care”. However keep in mind that combination VCC_SEL1 = VCC_SEL2 = GND and CMDVCC =

high initiates deep shutdown mode.

1.8 V

High

High

5 V

High

Low

3 V