ST25DV04K datasheet(35/200 Pages) STMICROELECTRONICS

35 / 200 page

5.2.2

GPO and power supply

When at the same time RF field is present and VCC is ON, GPO is acting as configured in GPO, GPO_CTRL_Dyn

and IT_TIME registers.

When the RF field disappears, the GPO state is reset and the output level is set to high-Z (open drain) or tied low

(CMOS). Interruption status in IT_STS_Dyn register is maintained until next I2C read or VCC power off.

Table 23. GPO interrupt capabilities in function of RF field

RF field on

RF field off

GPO state is function of RF events (1)

GPO remains High-Z (OD) or tied low (CMOS)

1. If pull-up resistor is powered (Open Drain-IE version), and VDCG is powered (CMOS –JF version).

When VCC is not present, or ST25DVxxx is in low power mode, all events are available on GPO pin, assuming

pull-up resistor is supplied with correct voltage (Open Drain-IE version) or VDCG is powered (CMOS-JF version).

The host can be waken up using GPO interrupt in any power condition.

The exception is FIELD_CHANGE when RF field is falling, which can’t be reported on GPO output if VCC is off or

in low power mode (no power supply on ST25DVxxx).

Table 24. GPO interrupt capabilities in function of VCC power supply

GPO events

VCC OFF

VCC ON and LPD high (1)

(low power mode)

VCC ON and LPD low(1)

FIELD_CHANGE if RF field

disappears

GPO remains High-Z (OD)

or tied low (CMOS)

GPO remains High-Z (OD) or tied

low (CMOS) (2)

Pulse emitted on GPO

Any other activated RF event

GPO state is function of RF

events(2)

GPO state is function of RF events(2)

GPO state is function of

RF events(2)

1. For STM25DVxxK-JF only.

2. If pull-up resistor is powered (Open Drain-IE version) and VDCG is powered (CMOS-JF version).

ST25DV04K ST25DV16K ST25DV64K

GPO

DS10925 - Rev 9

page 35/200

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