RFID Mifare card

- Apr 13, 2018-

Mifare card is a series of RF cards conforming to ISO14443A produced by NXP, including Mifare S50 card, Mifare S70 card, Mifare UltraLight card, Mifare Pro card, Mifare Desfire card, etc.

The mifare card most commonly used as membership card, payment cards, VIP cards, tickets, identification cards, etc.

Mifare series cards sometimes use Mifare UltraLight as MF0, Mifare S50 and S70 as MF1, Mifare Pro as MF2, and Mifare Desfire as MF3.

The common feature of the Mifare series is compliance with the ISO 14443A international standard. These common characteristics are described as follows:

1. They are close to the card PICC (Proximity ICC), reading and writing distance usually less than 10cm.

2. Their radio frequency is 13.56MHz±7KHz, also known as High frequecy cards.

3. These cards are passive and contactless, and the energy is provided by the RF field generated by the reader.

4. The magnetic field intensity of the RF field produced by the reader/writer is between 1.5A/m and 7.5A/m, and the card can work continuously and continuously within this field strength interval.

5. The card first enters the radio frequency field of the reader to complete initialization, and then waits for the reader's command. Data exchange between the reader and the card always uses the RTF mode, ie, the reader first issues a command and the card responds to the command within a specified time. If the reader does not have an order, the card cannot be spoken anyway.

6. The reader sends a Modified Miller code that uses 100% ASK modulation to the card, and a Manchester side code that uses subcarrier modulation for the card response.

7. When the card does not enter the RF field, it is called the Power-Off state. After entering the RF field, it enters the Idle state after power-on reset. After receiving the call command from the reader, it enters the Ready state. After the anti-collision cycle is selected, it enters the Active state, and enters the Halt state after receiving the dormant command or the unknown command in the active state.

8. These cards have a globally unique serial number, which may be 4 bytes, 7 bytes or 10 bytes in length. When multiple cards enter the reader's RF field at the same time, the cards observe the bit-oriented anti-collision mechanism and the card reader selects the only card to operate. After the reader has finished operating a card, a sleep command can be sent to put this card into hibernation, and the reader continues to operate on other cards.

9. The operation steps of these cards before the card selection (including) are the same. The operation after the card selection is not the same, for example, some need to verify the password, some do not need, and there are differences in the way to verify the password.