Questions about ST25 NFC Reader’s Tag Read Speed and Multi-Tag Handling

[StarryLiu]

Hi,

I’m exploring the ​ST25 NFC Reader for a ​bio-tracking application that requires ​fast tag read speeds and reliable ​multi-tag detection. However, I couldn’t find detailed specifications in the datasheet regarding these aspects.

I’ve also purchased the ​STEVAL-ST25R200SA kit, but its provided GUI doesn’t seem to support tag read speed evaluation. Could you help clarify:

1. ​Tag Read Speed:

   • What is the approximate ​read speed (tags/second) for the ST25 series (e.g., ST25R3916B)?
   • Is there a document (e.g., application note or performance report) that quantifies this?

2. ​Evaluation Tools:

   • Are there other ​ST evaluation boards (e.g., X-NUCLEO-NFC08A1) that include tools to measure read speed?

3. ​Multi-Tag Considerations:

   • When multiple tags are present in the ​ROI (e.g., 5 tags), what factors should I consider?
   • For example, could ​tag-to-tag coupling cause interference?

Context:

• Tags: Small ​ISO/IEC 15693 glass tubes (2mm × 12mm).

Thanks in advance for your insights!

[mike-john · Accepted solution]

I ran into similar limitations when evaluating ST’s NFC readers for a multi-tag application. The GUI tools are great for basic tests but fall short for benchmarking real-time performance. You might want to dig into ST’s application notes—especially those around ISO 15693 anti-collision and multi-tag reading. Also, switching to something like the X-NUCLEO-NFC08A1 with a custom firmware approach gave us more flexibility in measuring read speeds and handling interference.

[StarryLiu]

Thanks for sharing your experience! I think I’ll eventually switch to the ​X-NUCLEO-NFC08A1 since it offers more flexibility for development.

By the way, in your experience, what’s the approximate ​read speed achievable with this setup? I’m targeting around ​50 reads per second—is that feasible with ISO 15693 tags?

[Brian TIDAL]

Hi,

can you elaborate on "What is the approximate ​read speed (tags/second) for the ST25 series"? Do you mean Inventory of the various ISO15693 tags in the operating field (i.e. retrieve the UID of each tag) or Inventory + reading of the tag memory content?

Rgds

BT

[StarryLiu]

Thanks for the clarification! Yes, I specifically meant the inventory speed (tags/second) for ISO/IEC 15693 tags in the operating field—not including memory read operations.

[Brian TIDAL]

Hi,

the typical NFC Forum collision resolution process includes a 1-slot Inventory followed by a 16-slot Inventory in case of collision has been detected during the 1-slot Inventory. Further 16-slot Inventory commands may follow when further collisions are detected.

Here a typical sequence with 5 tags in the field of a ST25R3916B reader:

In dark blue, the Inventory Requests and in light blue the Inventory Responses. The 1st command is a 1-slot Inventory followed by collisions (5 tags replying). The 2nd command is a 16-slot Inventory followed by 5 answers in slots 1, 5, 7, 8 and 9 without collision. 

So basically the inventory speed is not reader dependent. Without collision during the 16-slot Inventory, one can expect to detect 5 tags in ~90ms if one of the tags replies in the last slot. In case of collision, further inventory commands are needed.

Hope this clarifies.

Rgds

BT

[StarryLiu]

Thanks for the details! The 90ms for 5 tags speed should work perfectly for my needs. Really helpful to know that inventory speed isn't reader-dependent.