AS3956 datasheet(50/107 Pages) AMSCO

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[v1-11] 2018-Nov-14

AS3956 − Detailed Description

The NFC device can then retrieve the data from the buffer by

sending a READ command to address FCh. The fourth word

contains the status flags as shown in Figure 48.

Figure 48:

Data Transmission from MCU to NFC Device

When the NFC device has successfully read all data from the

buffer, it shall clear the buffer and prepare for further data

transfer by issuing a WRITE command to address FFh. This will

trigger a Tx end interrupt.

If a READ command is received on address FCh prior to the

Transmit Buffer command, AS3956 will return zero data, io_busy

set to 1 and io_data_rdy set to 0. A NFC device can then poll

AS3956 by continuously sending READ commands at address

FCh and waiting until the last word equals 01h.

A READ command can be issued only to address FCh. Issuing a

READ command to any other address than FCh while in

Extended mode shall be treated as an error.

In Extended mode, it is assumed that AS3956 will always receive

16 bytes and transmit 12 bytes of data, 3 empty bytes and 1

byte for FLAGS. If the message size differs in any direction, then

the MCU or NFC device are responsible for proper error

management.

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AS3956 Datasheet(PDF) 50 Page - ams AG