RI-TRP-DR2B: Reading the Page 1 of DR2B-40, we found the data is wrong but the BCC is correct

Hello Ching,

I tried to understand the problem but was not able to understand the pictures. You wrote in the subject the data is wrong but the BCC is not.

Both pictures are described as data and BCC correct. In the second picture only 7 bytes of data are marked. Is this correct?

Please explain the problem with an example of the not correct data you receive.

Is the 13cm, where you noticed the problem, the far end of the reading distance?

Best regards,

Helfried

Hi Helfried,

Thank you for your info, we used the same transponder (DR2B-40) and RFID reader to do this test.

We put "RS0704" into the DR2B-40, we just moved the tag position from 12cm to 13cm and then we found the reading content is wrong but the BCC is correct. We used the other two DR2B-40 tags to do and got the same issue from reading results, too.
We suspect there is something wrong in the Tag IC of DR2B-40, so the RFID tag transited the wrong info to the RFID reader.

Another, we had used the old version DR2B-30 (wrote with the same data) and used the same RFID reader to test the reading status, we found the DR2B-30 never have the wrong data and the correct BCC. The DR2B-30 is very stable to transmit data to the RFID reader during one hundred cycle reading tests at the 13cm reading distance.

Regards,

Herbert Kang/ Ching Ying Kang

P.S. Herbert is my English name.

Hello Herbert,

the RD2B-40 and the DR2B-30 both have the same silicon chip. The differences between these transponders are production related and the DR2B-40 has a slightly longer antenna.

When looking at the screenshots you provided, I see that in the bad case the protocol is shifted by one bit (one bit is missing at the begin). To come closer to the problem we have to see if really the transponder is responding not the correct data, or if the reader is not able to detected it correct.

If you have the possibility to check the transponder response with a pickup coil and scope and check if the response is different when moving from 12cm to 13cm this would be helpful.

A few questions from my side:

What reader are you using? Is this a general problem with all your DR2B-40 transponders? Have you a different reader to check if it shows the same behavior? Is the bad response a response to a "Charge Only" read or a page read command?

Best regards,

Helfried

Hi Helfried,

Thank you for your help. We will analyze the data transit of TMS3705, we hope to clarify the relationship between raw data and the reading distance later.

Our answer is below,

Q1. What reader are you using?

Ans. This reader is made by ourselves and provides to our Semicon customers in Taiwan and South-east Asia.

Q2. Is this a general problem with all your DR2B-40 transponders?

Ans. Yes, we used the new five pcs to test and got the same result. And we used the DR2B-30 to test but did not have the same issue.

Q3. Have you a different reader to check if it shows the same behavior?

Ans. Yes, I used my friend's reader but this reader had the filter error content function, so these readers did not have the same issues.

I asked my friends why to add this filter function, he said that he even met the same issue, he can not resolve it before, so he used the firmware of the reader to resolve it.

Q4. Is the bad response a response to a "Charge Only" read or a page read command?

Ans. We used the page read command because we need to read page1 and page 2 for the customer's application.

Regards, Herbert