Hello and thanks for reading. We are using the M24SR02 and are having a problem where, when the length of the payload is exactly 31 characters, we cannot read the payload with a phone or other device.
We tested both with our hardware and the dev board, and the problem is consistent with both, which rules out an antenna or power supply issue.
We know that when we add or subtract a byte, everything works fine. We also seem to have good and bad chips, although the bad chips always do the thing and the good chips never have the issue so at least its consistent and reproducible.
When we read back the data from the M24 everything looks good, here are the readbacks (all data in hex):
System: 00 12 01 00 11 00 01 00 02 82 00 23 77 9E 6B 00 FF 82
CC: 00 0F 20 00 F6 00 F6 04 06 00 01 01 00 00 80
NDEF: [ 00 24 D1 10 20 55 04 ] [61 62 63 64 65 66 67 68 69 6A 6B 6C 6D 6E 6F 70 71 72 73 74 75 76 77 78 79 7A 61 62 63 64 65]
Any help or suggestions would be appreciated, as everything looks right from what I see. When I have a good chip, or a different-length payload on a bad chip, it works fine and I can read my data on my phone with the NFC Tools app. When I have a bad chip with the bad length, the app detects the chip and gets some data like the serial number, which matches what we expect in the system readout, but no payload.
I cant just replace the bad chips because I have several thousand boards, and I could just add a an extra char to the payload but Id like to have an explanation whats going on first.
Thank you!
