How Can I Logically Partition User Memory in a Bank of High-Capacity UHF RFID Tags?

I require ease of access for particular memory locations during read-write operation, similar to the partitioning of our pen-drives and hard disk. What would you recommend?

—Ssudhanshu

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Ssudhanshu,

To answer your question, I reached out to Ken Traub, principal at Ken Traub Consulting and a leading authority on passive ultrahigh-frequency (UHF) RFID software and standards. Here is Ken's response:

"The UHF Gen2V2 specification has a new feature called 'files,' which allows the user memory to be partitioned. In a tag that supports the file feature, it is possible to divide user memory into one or more partitions. When the reader communicates with the tag, it sends a command to select a particular partition; subsequent commands to read or write user memory are interpreted relative to that partition. Each partition can have a different size, and different access privileges."

NXP Semiconductors' Ucode DNA chip and Impinj's Monza R6 and Monza R6-P chips comply with the EPC Gen2V2 standard. Tageos makes nine tags that are available with these Monza chips. Avery Dennison offers four such tags, including the AD-661R6-P and the AD-680R6-P.

Smartrac manufactures two tags with the Ucode DNA chip, two tags with the Monza R6-P and seven tags with the Monza R6. You can find listings of the Smartrac EPC Gen2V2 tags here, here and here.

If you are working with a tag that doesn't have a chip fully supporting the UHF Gen2V2 specification, you can still arrange for your software to use different portions of memory for different purposes. "All software interacting with the tag has to be aware of the partitioning scheme you want to implement," Ken says. "Then it's a simple matter of using the right addresses. For example, if I want to have one partition that is 1,024 bits long, a second that is 512 bits long and a third that is 256 bits long, then software would use addresses 0 to 1,023 for the first partition, addresses 1,024 to 1,535 for the second and 1,536 to 1,791 for the third."

—Mark Roberti, Founder and Editor, RFID Journal