ST25R3920B datasheet(60/158 Pages) STMICROELECTRONICS

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Application information

ST25R3920B

60/158

DS13890 Rev 4

4.4.1

Set default

This direct command puts the ST25R3920B in the same state as power-up initialization:

•

performs Stop all activities command

•

resets all registers to their default state

•

clears all collision bits

Results of previous calibration and adjust commands are lost. No IRQ due to termination of

direct command is produced.

4.4.2

Stop all activities

This direct command stops any ongoing activities:

•

performs Clear FIFO command

•

stops data transmission and reception

•

stops all timers, including FDT timer

•

clears IRQ line an IRQ status bits

•

stops Field ON commands

If Stop All Activities is received during RF collision avoidance the field detection is

terminated and field is not set, consequently no interrupts are sent

•

stops automatic field ON (same as above)

•

stops automatic field OFF

If Stop All Activities is received during waiting for automatic field off via GPT, the field

remains on

•

nfc_ar is set to 01b, then it clears the awareness that there was a previous reception

•

stops Temporary Enable

This command does not update any register apart from the FIFO status registers. Therefore

it does not disable the field detector in CE mode (if it was enabled), and it does not switch off

the field (if it was enabled).

4.4.3

Clear FIFO

This direct command clears the FIFO and the FIFO status registers. It does not clear the

IRQ line or IRQ status bits.

Enables R/W access to register

Space-B

Yes

all

Test access

Enable R/W access to Test register

Yes

All

Other

codes

RFU

Not used

1. Defines which Operation control register bits have to be set in order to accept a particular command.

2. Measure amplitude and Measure phase can be used directly from power down mode. In this case the command

temporarily enables the oscillator.

Table 12. List of direct commands (continued)

Code

(hex)

Name

Comments

Chaining

Interrupt after

termination

Operation

mode(1)

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