Using the ST25RU3993 how do I request the EPC and a tags TID

[CShac]

I have distilled the example code provided for the ST25RU3993 evaluation kit down to issue a query, look for an RN, issue an ack and read the fifo on successful reception of the EPC number. I there a command other than the Query command that I can use to issue a request for the EPC and the TID number?

I have attached the code I have implemented so far for a bit of clarity.

[Bart Herse]

Hello Chris,

the Query command is needed to initiate tag inventory - there is no other command for this purpose. Once the Query command has been issued the remaining anti-collision slots need to be serviced by the QueryRep command. After the Query command it is also possible to send QueryAdjust to resize the number of anti-collisions (AC) slots are just to command the tags to draw new AC slots.

To get the TID it is necessary to singulate the tag first and then (depending on the access PW) access the TID memory by a ReqRN + Read command.

Cheers,

B

[CShac]

Hi Bart,

Thanks for replying. I'm a complete newbie to RFID and Interrogators as is probably evident. In my application there should only ever be one tag readable by the interrogator. Given the code above how does the tag singulate?

With the ReqRN command I see that I need to write the code 0x9F out on the SPI line. Are there any other values that need to be written into the fifo in a similar way to the query command.

in an almost pseudo code fashion:

• singulate tag
• write REqRN command
• wait for response. ( I think I obtain a handle here)
• write into the fifo 0x02 (I think this is the command for reading the TID) followed by handle
• wait for response

[Bart Herse]

Hello Chris,

No need to build the code from scratch.

Please download the reference FW code from the ST25RU3993-EVAL specific webpage on ST.com. From there you can see and use the FW code for tag interaction.

Cheers,

B

[CShac]

Hi Bart,

The reason for rebuilding is so that I can use the St25RU3993 on another board with a different micro controller. I'm attempting to integrate RFID reading in another project. I dont have the memory to take the entire FW from the Eval kit. Hence the desire to trim back as much as possible.

Chris