Mifare S50 card technology Analysis

Philips Electronics is a leading manufacturer of RFID chips. Therefore, this article takes Mifare S50 as an example to analyze the structure of RFID Card and the communication and storage technology of its chip. The chip has an unique MIFARE RF(radio frequency) contactless interface standard which has been established as an international standard--ISO/IEC 14443 TYPE A standard, which is widely used.

1. Mifare S50 card structure and main features

Mifare S50 card is a contactless IC card, also known as RFID card (radio frequency card). RFID card is a new technology that has developed vigorously in the world in recent years. It successfully combines RFID technology with IC card technology, solves the problem of no power supply and contactless use in the card, and is a great breakthrough in the field of electronic devices.

The electrical part of the Mifare S50 card consists only of an antenna and an RFID chip. The antenna is a set of coils with only a few wires wrapped in an ISO card. Data storage period is 10 years, can be rewritten 100,000 times, read unlimited times. The communication between card and reader adopts international DES and RES security cross algorithm, which has high security performance. 

2. Mifare S50 card's RFID chip internal structure

The chip of Mifare 1S50 card is composed of RF-interface (radio frequency Interface) and Digtal Section(digital module).

3. RFID chip communication technology for Mifare S50 card

The communication rate between the card and reader is 106 KB /s. When transmitting signals from card to reader, the subcarrier frequency is 847 kHz(FC /16), Manchester encoding method is adopted, and on-off Keying (OOK) is used to modulated signals. When the reader transmits the signal to the card, the RF carrier frequency is 13.56 MHz, using synchronous timing, improved: Miller encoding mode, modulation depth of 100% ASK(Amplirude Shift Keying) signal.

4. The RFID chip of Mifare S50 card supports multi-purpose storage technology

The capacity of E2PROM Memory in the chip is 8 kH, divided into 16 sectors, each sector is 4 blocks (block 0 ~ block 3), that is, the whole E2PROM Memory is 64 blocks, block number address is 0 ~ 63, each block is 16 bytes (0 ~ 15B), one access unit. Block 0 for each sector (note: block 0 of sector 0 is an exception, which is used to Store vendor code and is already solidified and cannot be overwritten.