ST25DV04KC datasheet(42/203 Pages) STMICROELECTRONICS

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I2C_RF_OFF:

•

When I2C_RF_OFF is activated, a pulse of duration IT_TIME is emitted:

–

after the I2C STOP condition of a successful I2C “RFSwitchOff” command if no RF write to EEPROM is

ongoing.

–

after the end of all blocks programming if the STOP condition of a successful I2C “RFSwitchOff”

command happens during an RF write to EEPROM.

•

The purpose of this GPO interrupt is to inform the I2C master when the I2C RFSwitchOff command has

switched off the RF (RF is in off mode), as the timing action of the I2C RFSwitchOff can vary if an EEPROM

write from RF is ongoing.

Figure 25. GPO/I2C_RF_OFF chronogram

1) I2C host sends a valid I2C RFSwithcOff command and there is no write in progress to EEPROM

memory from RF. RF is swithced off immediately and GPO/I2C_RF_OFF generates a pulse during

IT_TIME after I2C STOP condition.

GPO/I2C_RF_OFF

3) I2C host sends a valid I2C RFSwitchOff command and I2C_RF_SWITCHOFF_EN = 0. RF is not

swithced off and the GPO/I2C_RF_OFF remains high-Z.

2) I2C host sends a valid I2C RFSwitchOff command and there is a write in progress to EEPROM

memory from RF. RF is switched off and GPO/I2C_RF_OFF generates a pulse during IT_TIME at end

of EEPROM programming.

GPO/I2C_RF_OFF

S I2C RFSwitchOff

A P

S I2C RFSwitchOff

A P

S I2C RFSwitchOff

A P

Wt(RF)

MS69216

5.4.3

GPO and power supply

When at the same time RF field is present and VCC is ON, GPO is acting as configured in GPO1, GPO2 and

GPO_CTRL_Dyn registers and both RF events ans I2C events are reflected to the GPO pin.

When VCC is ON and no RF field is present, GPO is acting as configured in GPO2 and GPO_CTRL_Dyn

registers, Only I2C events are reflected on the GPO pin. IT_STS_Dyn register is maintained unchanged until next

I2C read of VCC power off.

When RF field is present and VCC is OFF, GPO is acting as configured in GPO1 (and GPO2 for IT_TIME

configuration only) and GPO_CTRL_Dyn registers. Only RF events are reflected on the GPO pin (assuming

pull-up resistor is supplied with correct voltage for open drain version, or VDCG voltage is supplied for CMOS

version). Exception is FIELD_CHANGE when RF field is falling, which can’t be reported on GPO output if VCC is

off (no power supply on ST25DVxxKC).

ST25DV04KC ST25DV16KC ST25DV64KC

GPO

DS13519 - Rev 3

page 42/203

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