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monitorwa

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Mifare access bits hex to binary covnersion

Hi,
I am trying to understand the conversion of binary code into hex for access bits on mifare cards. Nxp has plenty of free pages on this but I'm obviously missing some under standing on how the values in the documents relate to what is programed into the card e.g Ff0708 converts to C1 c2 c3 which equals the binary value of 001
I'm sure I'm not giving enough info so ask and I will answer where I can
Thanks
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kraiven

I'm afraid I don't know anything about the card you are using and I really don't understand how the Hex you gave gets to 001. But the general rule for converting Hex to binary is the each Hex number is equivalent to 4 binary values:

i.e. F (Hex) = 1 1 1 1 (Bin) = 15 (Dec)
      1 (Hex) = 0 0 0 1 (Bin) = 1 (Dec)
      2 (Hex) = 0 0 1 0 (Bin) = 2 (Dec)
      4 (Hex) = 0 1 0 0 (Bin) = 4 (Dec)
      8 (Hex) = 1 0 0 0 (Bin) = 8 (Dec)
      A (Hex) = 1 0 1 0 (Bin) = 10 (Dec)

hope that helps
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TommySzalapski
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ASKER

Thanks your advices got me through it, on the actualy Mifare 1 k classic which is the card concerned C1 - C3 actually have 4 values each e.g C1 (0-3) so C1(2) - C3(2) reltae to different blocks of the card. I used your method for the rest and it worked out OK

thanks again

Dave