AN3433

Management of CR95HF or STRFNFCA activity

Doc ID 019046 Rev 2

9/34

2.3

Idle command parameters

The Idle command (Host to device) has the following structure (all values are hexadecimal):

CR95HF or

STRFNFCA

to Host

0x00

Result code

This response is sent only

when CR95HF or STRFNFCA

exits WFE mode.

<<<0x000101 Wakeup by

timeout

<<<0x000102 Wakeup by

tag detect

<<<0x000108 Wakeup by

low pulse on IRQ_IN pin

0x01

Length of data

<Data>

Data (Wakeup source)

CR95HF or

STRFNFCA

to Host

0x82

Error code

<<<0x8200

Invalid command

length

0x00

Length of data

1.

An initial calibration is necessary to determine DacDataL and DacDataH values required for leaving Tag

Detector state. For more information, contact your ST sales office for the corresponding application note.

Table 4.

Idle command description (continued)

Direction

Data

Comments

Example

Table 5.

Idle command structure

07

0E

xx

yy zz

yy zz

yy zz

aa

bb

cc

dd ee

ff

gg

Comma

nd code

Data

length

WU

source

Enter

Control

WU

Control

Leave

Control

WU

Period

Osc

Start

DAC

Start

DAC

Data

Swing

Count

Max

Sleep

Table 6.

Summary of parameters

Parameter

Description

Command code

This byte is the command code. ‘07’ represents the Idle command. This

command switches the device from Active mode to WFE mode.

Data length

This byte is the length of the command in bytes. Its value depends on the

following parameter values.

WU Source

This byte defines the authorized wakeup sources in the wakeup source

register. Predefined values are:

01: Time out

02: Tag Detection

08: Low pulse on IRQ_IN

10: Low pulse on SPI_SS

Enter Control

These two bytes (EnterCtrlL and EnterCtrlH) define the resources when

entering WFE mode.

0x0400: Hibernate

0x0100: Sleep (or 0x2100 if Timer source is enabled)

0xA100: Tag Detector Calibration

0x2100: Tag detection

WU Control

These two bytes (WuCtrlL and WuCtrlH) define the wakeup resources.

0x0400: Hibernate

0x3800: Sleep

0xF801: Tag Detector Calibration

0x7901: Tag detection