CN102567696A

CN102567696A - Method for calculating time interval for ultrahigh-frequency electronic tag to respond to reader

Info

Publication number: CN102567696A
Application number: CN2010106223062A
Authority: CN
Inventors: 余秋芳; 张建平; 苏伟
Original assignee: Beijing CEC Huada Electronic Design Co Ltd
Current assignee: Beijing CEC Huada Electronic Design Co Ltd
Priority date: 2010-12-27
Filing date: 2010-12-27
Publication date: 2012-07-11

Abstract

The invention discloses a method for calculating a time interval T1 for an ultrahigh-frequency electronic tag to respond to a reader. The T1 refers to the time interval from the end of the transmitting of the reader to the responding of the tag. In the method, the tag judges whether to generate a backscattering clock according to the correctness of the received command and whether the tag needs to return back data, thereby calculating the T1. The method can realize the following aims of: 1, ensuring that the time interval T1 from the end of command transmitting of a card reader to the data returning of the tag is controlled in a range specified by a protocol; and 2, facilitating implementation of a low power consumption mode of the ultrahigh-frequency electronic tag.

Description

A kind of ultrahigh frequency electronic tag method in the response reader time interval of calculating

Technical field

The present invention proposes a kind of method of calculating ultrahigh frequency electronic tag response reader time interval T1.This invention is applicable to ultrahigh frequency electronic tag logical design field.

Background technology

The present invention proposes a kind of method of calculating ultrahigh frequency electronic tag response reader time interval T1.When reader and label communication, T1 is an important detection index, and it indicates that reader sends the time interval that finishes between the label response, if T1 is too short, reader possibly also not handled internal processes, thereby can't handle the response that label returns; If T1 is long, reader possibly think that label is not in this radio-frequency field.

T1=N*Tpri, Tpri are label backscattering clocks.Usually reader is with recognition cycle of Query order beginning, and Query has also confirmed the divide ratio of Tpri with respect to system clock simultaneously, generally speaking; After having confirmed divide ratio, label will produce new frequency-dividing clock, but this can bring a problem; It is exactly the clock that frequency division produces; Be that the data that backscattering clock and reader send are fully asynchronous, if first of ED point and backscattering clock is effective in maximal value and the minimum difference of the time that differs greater than T1, this difference+N*Tpri is just greater than T1 so; If other is T1=(N-1) * Tpri; When the maximal value of T1 and minimum difference approached 0, this difference+(N-1) Tpri will can not meet the demands less than T1 equally so.

Summary of the invention

To the problems referred to above, what the present invention proposed is a kind of effective method for designing, not only satisfies the requirement of T1, but also helps the realization of low power dissipation design.

1, in this method for designing, confirm whether the order of the current reception of label is correct, whether need return response.

2, in the process of label reception order, turn off the backscattering clock.

If the order that 3 labels receive is correct and need response, just when receiving end, begins that system clock is done frequency division and handle, to obtain the backscattering clock.

If 4 labels have begun to produce the backscattering clock, read the order of sending but in the process of calculating T1, receive again, this explains that this order length surpasses the length of correct order, cuts off the backscattering clock immediately.

If the order that 5 labels receive does not need response, label does not produce the backscattering clock.

If the order that 6 labels receive is too short, or before receiving end, take place unusually, label does not produce the backscattering clock.

Through this method, the error control on end point and first effective edge of label backscattering clock that can reader be sent data is in two system clock cycles, and this can satisfy the error range of T1 fully.This method can be controlled label and get into low-power consumption mode simultaneously.Under this pattern, the value of the register relevant with the backscattering clock remains unchanged, thereby has reduced power consumption effectively.

Description of drawings

All example among the figure with N=10

Before accompanying drawing 1 had been described and do not used this method, first effectively differed situation far away in the edge ED point that reader sends and backscattering clock.

1.t1 be the ED point of reader transmission and the error on first effective edge of backscattering clock.

2. first the effective edge from Tpri begins to count 10 Tpri.

3. the T1 of actual computation equals 10*Tpri+t1 in fact, and this value has surpassed the scope that T1 allows.

Accompanying drawing 2 has been described and has been used the T1 that produces after this method.

1. before reader sent ED, Tpri was 0 always.

2. reader sends and finishes back generation Tpri, and error t1 is in two system clocks.

3. the T1 of actual computation equals 10*Tpri+t1, in the scope of T1 permission.

Embodiment

The key that the present invention implements is when label produces the backscattering clock, thereby confirms T1.

1. label receives in the process of order, and which bar order receives what can confirm current reception after the command header is, and can confirm the correct length that this order should receive;

2. whether needs return response to label according to current command determination;

3. return response if desired, receive the data of designated length when label after, system clock is carried out frequency division by the divide ratio of being confirmed by Query order, produce the backscattering clock;

4. with the backscattering clock count that generates;

5. counter is from 0 to N the time, and label can return response.

Claims

1. one kind is calculated the method that ultrahigh frequency electronic tag responds reader time interval T1, it is characterized in that step is following:

Which kind of order what (1) label was judged current reception according to the several leading bit data that receives is, and then judges the data length that this order should receive;

(2) after label is received the order of designated length, judge whether to return response; If response is returned in labeling requirement, receive the data of designated length when label after, system clock is carried out frequency division by divide ratio, produce the backscattering clock, otherwise the backscattering clock is 0;

(3) use the backscattering clock count, when count value reaches T1 during the time, the backscattering clock becomes 0 again, and label begins return data simultaneously;

2. a kind of method of calculating ultrahigh frequency electronic tag response reader time interval T1 as claimed in claim 1 is characterized in that in the process that receives order, the backscattering clock of label is 0.

3. a kind of method of calculating ultrahigh frequency electronic tag response reader time interval T1 as claimed in claim 1 is characterized in that, if find that order is unusual, turns off the backscattering clock immediately, and then stops to calculate T1.