UM0853 datasheet(22/56 Pages) STMICROELECTRONICS

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How to control the RF and I²C channels from your screen

UM0853

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Doc ID 16609 Rev 3

Figure 33.

Selecting the Non-addressed mode

Addressed mode

Selecting the Addressed mode clears bit 5 and sets bit 6 in the Request_flags of the RF

request (bit 5 = 0, bit 6 = 1).

The request is addressed. The UID field is present (please refer to the M24LRxx datasheet

for details).

After an Inventory command (see Section 3.2.2: Inventory command), you will be able to

click on an UID to select a specific tag. The desired UID will be sent with the request if the

Addressed mode is chosen.

If no specific UID tag is selected, the device sends “00 00 00 00 00 00 00 00” instead of the

UID value.

Figure 34.

Selecting the Addressed mode

Select mode

Selecting the Select mode sets bit 5 and clears bit 6 in the Request_flags of the RF request

(bit 5 = 1 and bit 6 = 0).

The request is executed only by the M24LRxx device in the Select State (please refer to the

M24LRxx datasheet for details).

To select a tag, refer to the SELECT paragraph below, and to the M24LRxx datasheet

(Select paragraph).

Figure 35.

Selecting the Select mode

3.2.6

Managing M24LRxx states

The M24LRxx can be in different states: Power-off, Ready, Quiet and Selected (refer to the

M24LRxx datasheet for details).

The interface shown in Figure 36 is used to send three types of RF request to place the

M24LRxx in one out of three specific states: Selected, Quiet and Ready.

Figure 36.

Device state management interface

SELECT

The SELECT button is used to send a Select RF request with the UID of a specific tag

(Section 3.2.2: Inventory command) (refer to the M24LRxx datasheet for details).

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