MB89R119B datasheet(13/46 Pages) RAMXEED

13 / 46 page

MB89R119B

DS411-00002-4v0-E

3. FeRAM Data Protection from RF Power Shutdown during Accessing FeRAM

MB89R119B accesses to FeRAM with the unit of 1 byte. When RF power is shut down during accessing

FeRAM, writing in FeRAM is completed by the charges stored in a smoothing capacitor on the LSI and

FeRAM data writing error is prevented.

Therefore, the commands of 1 byte access such as Write AFI, Write DSFID, Write EAS, and Lock command

can protect the data from the power down.

On the other hands, the commands of more than 2 bytes access such as Write Single Block command may

not protect all the data from the power down during the access. In this case, it is recommended to confirm

the data correctness by a read command.

4. Requests/Responses

A request is sent from the reader/writer to the transponder. In replying to the request, the transponder sends

a response to the reader/writer.

Request, and response, are transmitted in a single frame.



Structure of requests and responses

Each request consists of the following fields :

• Flags

• Command code

• Parameter (required or optional depending on the command)

• Application data fields

• CRC

Each response consists of the following field :

• Flags

• Parameter (required or optional depending on the command)

• Application data fields

• CRC

Amultiple byte field is transmitted least significant byte (LS Byte) first, each byte is transmitted least significant

bit (LS Bit) first.

5. Operating Modes

The MB89R119B has the following 3 operating modes :

The term mode refers to the mechanism to specify in a request the set of reader/writer that shall answer to

the request :



Addressed mode

When the Address_flag is set to “1”, the request shall contain the unique ID (UID) of the addressed

MB89R119B. Any MB89R119B receiving a request with Address_flag set to “1” shall compare the UID to its

own ID. If it matches, it shall execute it and return a response to the VCD as specified by the command

description. If it does not match, it shall remain silent.



Non-Addressed mode

When the Address_flag is set to “0”, the request shall not contain a UID. Any MB89R119B receiving a request

with the Address_flag (bit 6) set to “0” shall execute it and shall return a response to the reader/writer as

specified by the command description.



Select mode

The MB89R119B enters Select mode when the Select_flag is set to “1”, and the Address_flag is set to “0”.

In Select mode, the request shall not contain a UID. When the transponders receive the command, only the

transponder in the select state executes processing and returns its response in accordance with the request-

ed command.

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