Hello!
Dear ST technician!
Using the chip STM32L476 +3993 provided by your company and the original code provided by the official,
I have encountered a problem of operating tags. I sincerely consult you here:
When the tags of GB29768 is inventory,
In tag memory, read from area:
Read operation of coding, Tag Information, Security, User,
"Could not read tag..." Warning, unable to operate,
Compared with gen2 tag, the above functions can successfully perform read and set operations,
detailed reading of the source code, see a complete preparation of GB29768 tags operation procedures,
the ST25RU3993 Reader Suite also feels perfectly functional,
So I'm glad to consult you, could you tell me what caused it?
I wish you good health!
ST loyal user
1 ACCEPTED SOLUTION
Accepted Solutions
Thank you very much for your reply.
There is no password and lock in these areas.
Using other companies' RFID reading and writing software, can access the GB29768 tag, and change the ID number of the tag.
The ST read-write software we use is as shown in the following figure. We also use the serial debugging tool and oscilloscope. The operation of the test level is as follows:
After ST "read" instruction was sent to 476MCU, 3993 found the corresponding tag and sent the access instruction to the tag. The oscilloscope tested that the complete wave pattern of access tag instruction was correct. So feel read and write GB29768 tag, code also write the corresponding program, But now can not access the tag, use serial debugging tool test code, error type is "-33", waiting for the response error, also hope to guide and help to solve, thank you very much!
best regards�?
伟民
Hello,
your issue cannot be reproduced in our lab.
Using the 2.0.0 from st.com (for your info, we released a new 2.1.0), I defined the same parameters as yours (cf attached).
I have been able to read the content of the tag (coding area, cf attached), this read is reproducible on multiple tags without error.
Your issue may be due to antenna tuning.
Are you using the near field antenna provided with the EVAL board or another one ?
Could you please try to change the pre-tuning algo to MEDIUM and disable the autotuning algo (cf attached) before the test ?
Last point, the error code -33 means "No response" so either the tag did not reply at all or the environment was so noisy (or antenna not tuned cf above) that the reader was not able to recognize the answer.
AFAIU you have an oscilloscope, could you check the tag is at least answering and that the reply is correctly formated ?
regards,
Cedric
Hello!
Dear ST technician!
Thank you very much for your timely reply.
And experienced the new code and new ST25RU3993 Reader Suite software in version v2-1-0-0.
According to the operation method you replied, the following Settings were made.
Strange is: access the tag yet error, using the serial debugging tool,
to find the error location and error message as shown in the figure below：
I hope to continue to receive your guidance. Thank you very much�?
best regards,
伟民
Hello,
It seems the tag is not answering to the access command, indeed as I mentioned above the code -33 means "No response" (the tag did not reply at all or the antenna is not tuned enough) but with the pre-tuning enabled I consider the tune is now OK.
Could you confirm this assumption by checking the waves with you oscilloscope and see if the tag is at least answering to the command ?
A small comment, you have to be really carefull with the printf, indeed the Gb29768 protocol is really sensitive to timings and printf may introduce extra timings that leads to out of ranges timings.
The least invasive approach would consist in filling up an array during execution and see the array content once the protocol has finished 😉
A test you could run: with 2.1.0 the GUI now allows to read the tag TID while inventorying (cf attached), this is roughly using the same mechanism being used for tag reading.
Could you try to launch inventories with different frequencies, coding, china profile, tc, rx/tx options, ... and check that at least a tag is inventoried (in main window, deploy a tag that has been found and its TID should be listed), then with this working setup try to read tag content.
regards,
Cedric.
Hello,
Dear Cedric，
Thank you very much for your continuous reply�?
"Printf" should be avoided in GB29768 as much as possible. I feel the same way as you.
What you said above：“...the GUI now allows to read the tag TID while inventorying...�?,
And there's a little bit of confusion here, but the “GB-29768 with TID�?setting is also used, and the tags cannot be search to.
Please refer to the following Settings for details:
Now using "gb-29768" setting can search to the tag, but cannot successfully access the tag, so I have added "printf" test error message to the error location. The test value is consistent with the result of the oscilloscope test. After the "SendCmdGetRn" command was send, the data returned by the tag has no response.
So as not to affect the program to normal execution, I also turned off the "printf" here, and continued to test, I still could not access the tag normally. The Error was: "FAIL: Could not read tag memory Coding (tag Error: memory overrun 0x3. Memory does not exist or is too small)", as shown in the figure below:
Above feedback, hope to continue to get your help, thank you very much!!
best regards,
伟民
