Writinging issue - 128 bit EPC tag with MC3090-Z

Team,   I managed to  write a tag via RFID API3 Sample3Plus App :


NXP U-Code G2iL

Interface Protocoll

EPC Class 1 Gen 2, ISO 18 000-6C


860 – 960 MHz


128 bit EPC

  But most of the time I receive following error message: Tag not found in the field (but it is there, nearby).

I suspect our demo appl. is not prepared for 128 bit EPC. Because all the new tags store the EPC on 128 bit and I suspect our "writer" manage only 96 bit.

Do you have some information concerning this? Or redirect me to the person who can help?

Rui Huang
There is no restriction on

There is no restriction on the length of EPC ID that can be written via RFIDSample3Plus application on MC3090-Z. User can follow steps below to write 128 bit EPC ID

1. In order to see tag's EPC ID whose length is greater than 96 bits, user should go to "Tag Storage Setting" window to set the maximum Tag ID length to a proper value, In this case, it shuld be 16 (bytes)  ( Menu -> Operations -> Tag Storage Settings )

2. If there is only one tag in the RF field that needs to be written, set the tag population value to 1 for both antennas (antenna index 1 & 2).
This value can be set in Singulation window ( Menu -> Config -> Configuration -> Singulation)

3. Set both antennas' power value to the max value(30 dBm) in the Antenna Config window
( Menu -> Config -> Configuration -> Antenna )

4. Write EPC ID in the Write Tag window 
Brief explanation on the various parameters in “Write Tag” Form 
Tag ID:  EPC ID of the selected tag
Password: If the tag has been locked, you need to enter the correct password before performing
                the write operation. If tag is not locked, then just enter 0
Memory Bank: select tag memory bank for write operation.
                 -   EPC MB: store tag’s EPC ID 
                 -   Reserved MB: contain tag’s kill and access passwords 
                 -   TID MB: Typically store tag’s chip info  
                 -   User MB: store user-specific data   
Offset: Offset of the first word to be written    
Length: the length of data    
Write Data - The data to write to the selected tag 

Note: The unit of both offset and Length is byte. And length should also be on word (2 bytes)  
         boundaries. In other words, it should be an even number

If you try to write 128 bit EPC ID, the Write Parameter settings should be:  
               Tag ID:  the selected tag's EPC ID in hex formate   
               Password:  0
               Memory Bank: EPC  
               Offset(Bytes):   4   ( bypass the CRC and PC words )
               Length(Bytes):  16
               Data(Hex):  total of 32 hex characters   

Hope the above information will be helpful!

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