2020-09-29 07:54 AM
Hello all,
I have an issue with CR95HF chip that it cannot return more than 62 data bytes (after deducting control and CRC bytes ) . The FiFo buffer should contain about 256 bytes.
I am using STM8 and i have my own implementation .
The issue happens with me while sending Read binary APDU command with 255 bytes length
when i read the received data from chip i found that there is 62 bytes only .
Thanks alot in Advance
Solved! Go to Solution.
2020-09-29 10:23 AM
Hi,
as explained in the previous post, I recommend E0 70 (i.e. up to 128 bytes).
I would suggest to check in the tag datasheet the maximum read size and align the read binary APDU request accordingly.
Rgds
BT
2020-09-29 09:08 AM
Hi,
I suspect that the issue is due to the FSDI parameter in the RATS sent in your implementation. The FDSI codes the FSD. The FSD defines the maximum size of a frame the reader is able to receive. My guess is that you send RATS = E0 50 i.e. FSDI=5 (64 bytes) and CID=0.
I would suggest to use FSDI=7 (128 bytes). As the <Len> parameter of the response from the CR95HF to the host is one byte, it is not possible to receive 256 bytes.
Also, NFC Type 4 tags have a MLe parameter in the CC file that specifies the Maximum number of bytes that can be read. Which tag do you use?
Rgds
BT
2020-09-29 10:13 AM
Hi,
Thanks alot for you reply.
Yes you are right when i adapt RATS commands to be E0 80 currently i can receive 255 bytes
but now there is unstable behavior that some time i request to read 200 bytes and receive 60 bytes and while i am repeating the read binary APDU , i receive different numbers ( 10 bytes , 64 bytes , 20 bytes and 130 bytes) .
Iam using 32k smart card based on infenion chip
2020-09-29 10:23 AM
Hi,
as explained in the previous post, I recommend E0 70 (i.e. up to 128 bytes).
I would suggest to check in the tag datasheet the maximum read size and align the read binary APDU request accordingly.
Rgds
BT
2020-09-29 10:30 AM
Hi,
Actually i have checked the datasheet of the card and i found that is supports up to 255 bytes
but what about unstable behavior of receiving data
2020-09-29 11:31 AM
Hi,
the CR95HF returns what it has received from the tag, so if what you received is segmented, well, the issue is likely on tag side.
Rgds
BT