ST25DV04K datasheet(38/197 Pages) STMICROELECTRONICS

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5.2.4

Configuring GPO

GPO and interruption pulse duration can be configured by RF user or by I2C host. One or more interrupts can be

enabled at same time.

RF user can use Read Configuration and Write Configuration commands to set accordingly the GPO and

IT_TIME registers, after presenting a valid RF configuration password to open RF configuration security session.

I2C host can write GPO and IT_TIME registers, after presenting a valid I2C password to open I2C security

session.

Enabling or disabling GPO output:

•

RF user and I2C host can disable or enable GPO output at power up time by writing in GPO_EN bit 7 of

GPO register (if write access is granted).

•

I2C host can temporarily enable or disable GPO output at any time by toggling GPO_EN bit 7 of

GPO_CTRL_Dyn register. No password is required to write into GPO_CTRL_Dyn register.

•

Disabling GPO output by writing in GPO_EN bit (either in GPO or in GPO_CTRL_Dyn registers) does not

disable interruption report in IT_STS_Dyn status register.

Table 33. Enabling or disabling GPO interruptions

GPO bit 7:

GPO_EN

GPO_CTRL_Dyn bit 7:

GPO_EN

GPO output

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

Activated RF events are reported on GPO output (1)

Activated RF events are reported on GPO output(1)

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

Interruption pulse duration configuration:

•

Interrupt pulse duration is configured by writing pulse duration value in IT_TIME register.

•

Pulse duration is calculated with the following equation

IT pulse duration equation:

ITpulseduration=301μs−IT_TIME×37.65μs±2μs

(1)

ST25DV04K ST25DV16K ST25DV64K

GPO

DS10925 - Rev 11

page 38/197

ST25DV04K Datasheet(PDF) 38 Page - STMicroelectronics