| 摘要 |
The contactless integrated circuit (IC2) comprises means for transmitting and receiving of data by an inductive coupling which include an antenna-inductor (L1) connected in parallel with a capacitor (C1), a decoding circuit (DECC2) which comprises two decoders (DEC20,DEC21) for decoding the coded data according to two protocols, and means which include the frame identification circuit (FIC) and a multiplexer (MUX) for automatic latching in one communication mode, that is for selecting the first or second decoding unit as a function of the profile of the frame start received at the beginning of the communication. The frame identification circuit (FIC) receives the falling and the rising edges detection signals (FED,RED), and delivers the start of frame detection signals (SOFD1,SOFD2) and a selection signal (SEL) directed to the multiplexer (MUX). The contactless integrated circuit also comprises a demodulator circuit (DEMC) which delivers the falling and the rising edges detection signals (FED,RED), and a clock signal extractor circuit (CEC2) which delivers the first clock signal (CK0) of determined frequency when the integrated circuit is in the first communication mode and the second clock signal (CK1) of different frequency when the integrated circuit is in the second communication mode. The frame identification circuit (FIC) comprises a counter, the decoding circuits for determining the times which define temporal windows, latches each with set and reset inputs and output Q, D-type synchronous bistables each with input D, clock input and output Q, AND gates, OR gates, and inverters. The output of multiplexer (MUX) is directed to a central unit (UC) connected to a memory unit (MEM) and to a coding circuit (CDC) which receives the data for transmission and delivers a load modulation signal (Slm) to a load modulation circuit (LMC), which is connected in parallel with the antenna-inductor (L1). The contactless integrated circuit comprises means for communicating with a reading unit according to at least two protocols, in particular the protocols ISO/IEC 15693 and ISO/IEC 14443-B, and means for automatic latching in a mode corresponding to one of the protocols as a function of the profile of the start of frame signal received at the beginning of the communication.
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