Forum › MIFARE and NFC Reader IC`s › OTP data › Reply To: OTP data
Hi Maratkuls,
Before you issue the card to the end-user you should set the maximal available rides left. If the user is allowed to get only 5 rides, you initialize the OTP counter with FFFFFFE0 (11…1100000). Of course you can also use 07FFFFFF, this depends on whether you prefer left or right shifting to count zeros or ones.
Your algorithm have to count the zeros of the OTP to determine if is any rides left. I would read the value and mask out 0x0000000001 and shift in a loop and check if it is zero or not.
The MIFARE Team
Before you issue the card to the end-user you should set the maximal available rides left. If the user is allowed to get only 5 rides, you initialize the OTP counter with FFFFFFE0 (11…1100000). Of course you can also use 07FFFFFF, this depends on whether you prefer left or right shifting to count zeros or ones.
Your algorithm have to count the zeros of the OTP to determine if is any rides left. I would read the value and mask out 0x0000000001 and shift in a loop and check if it is zero or not.
The MIFARE Team
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