Radio frequency identification label chip data receiving synchronous method

Abstract

The method provides a method for synchronously receiving data of an RF identification tag chip which is applicable to an ISO / IEC 18000-6 Type B protocol. In the method, two counters are used to respectively count the lengths of a high level and a low level in an instruction format which conform to the ISO / IEC 18000-6 Type B protocol, and an adder matched with the bits of the counter is used to perform an accumulation operation, a synchronous count value is temporarily stored in a register block, and a comparator is used during sampling to compare the count value with a reference value obtained by the accumulation operation and a division operation to give a correct sampling clock edge. The specific method comprises a stage of counting the length of the high level by a high-level counter in a set time; a stage of waiting for an instruction frame header to start; a stage of receiving the instruction frame header; a stage of receiving an identification separator and a stage of receiving sampling data. The method has strong adaptability to low-stability on-chip clocks, a simple circuit realization structure, and just needs two counters, i.e. the adder and the comparator, a plurality of registers and a small state machine controlling the synchronous data flow.

Description

technical field [0001] The invention relates to a method for synchronizing data reception of an identification tag chip. In particular, it relates to a radio frequency identification tag chip data reception synchronization method with strong adaptability to the low-stability on-chip clock. Background technique [0002] The radio frequency identification (RFID) system consists of three parts: a radio frequency tag (Tag), a card reader (Reader) and a data management system. A radio frequency tag chip usually consists of an analog front-end circuit, a digital processing unit and a memory. [0003] For passive RFID tags, the tag first waits for the reader to issue a command, and then responds. In this case, the tag needs to recover the data modulated and encoded by the reader. Since the operation of the card reader and the tag adopts independent clock sources, the two are in a completely asynchronous clock domain. In order to correctly sample the relevant commands, the tag m...

AI Technical Summary

Problems solved by technology

The synchronous sampling error is mainly due to the fact that when the clock frequency jitters, the correct sampling clock edge cannot be generated, resulting in data sampling errors

[0005] Another way to get synchronization with the card reader is to use double-edge triggering, this method can effectively reduce power consumption, but it will cause relatively complex timing issues

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