Hello,
You can get the size of a memory card from the second byte of its ATR.
According to ISO 7816-3, the 3 LSB of this byte define the length of data
units (in bits), and its 4 next bits, the number of data units as :
= No size specified
0001 = 128 data units
0010 = 256
0011 = 512
0100
Do you know if your cards comply with ISO 7816? Or perhaps they use one of
the other interface protocols not recognised by ISO (e.g. I2C). Or maybe its
the other way round: your cards are 7816 compliant but the reader is not.
Memory cards are an area where you have to be sure that the card and
