AS3956 datasheet(49/107 Pages) AMSCO

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ams Datasheet

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[v1-11] 2018-Nov-14

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AS3956 − Detailed Description

When MCU reads out the data from the buffer, data will be sent

to MCU in the same order as they were stored in the buffer

starting from address 00h. When MCU has read all buffer

content, it shall issue a Clear Buffer command to clear the flag

rf_data_rdy. At this point, a new data message can be received.

Figure 47:

Data Reception in Extended Mode

MCU to NFC Device Data Flow Protocol

NFC devices can receive data from a MCU through AS3956 by

using standard READ commands.

Prior to writing data into the buffer, the MCU shall issue a Clear

Buffer command to AS3956 to ensure data are correctly

mapped into the buffer. To start data transmission, the MCU

shall issue then a Transmit Buffer command. In this way, the flag

io_data_rdy is set and data can be transmitted to the reader.

The transmission of the data from the tag to the NFC device is

done by issuing a READ command on block FCh. The fourth

block being read during the read command contains the status

flags of the ongoing communication.

NFC devices can receive data from a MCU through AS3956 by

using standard READ commands.

Prior to writing data into the buffer, it is advisable that to issue

a Clear Buffer command to AS3956 to ensure data are correctly

mapped into the buffer. MCU can trigger data transmission by

writing three words of data into the buffer at addresses

FCh-FEh, and issuing a Transmit Buffer command. This will also

set io_data_rdy flag. The transmission of the data from the tag

to the read is done by issuing a read command on word 0xFC.

PCD

AS3956

MCU

Rx end

Rx start

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