Transmitter/receiver for a vehicle and transmission/reception method of the transmitter/receiver for vehicles

• US 6,263,197 B1
• Filed: 10/24/1997
• Issued: 07/17/2001
• Est. Priority Date: 04/27/1995
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Tokai RIKA Denki Seisakusho
• Original Assignee: Kabushiki Kaisha Tokai RIKA Denki Seisakusho
• Inventors: Noda, Takahisa, Umeda, Fumio, Shibagaki, Yuuzi
• Primary Examiner(s): Maung, Nay
• Assistant Examiner(s): Trinh, Sonny
• Application Number:
  US08/945,174
• Time in Patent Office: 1,362 Days
• Field of Search: 455/186.1, 455/352, 455/343, 455/420, 455/40, 455/419, 380/23, 380/49, 380/21, 380/42, 380/262, 380/247, 380/248, 380/271, 340/825.72, 340/825.31, 340/825.34, 714/18, 714/48, 714/52, 375/358-359
• US Class Current: 455/186.1
• CPC Class Codes: G07C 2009/00253 dynamically, e.g. variable code - rolling code
• CPC Class Codes: G07C 2009/00793 by Hertzian waves
• CPC Class Codes: G07C 9/00182 operated with unidirectional data transmission between data carrier and locks

Abstract

A memory (30) of a transmitter (12) of a transceiver (10) for a vehicle has four writing error check areas in which “Low” is written at the beginning of a writing process and “Hi” is written at the end of the writing process. As a result, when the writing error check area is read in a data reading process, it is possible to confirm whether writing has been finished correctly. Further, there are provided four rolling code data storing areas in the memory (30). The area which is written into is changed each time a rolling code is incremented. When transmission data is read, if data within a writing error check area is “Low”, data is read from the previous rolling code area, and on the basis of the read data, transmission data is generated.

Claims

1. A transceiver for a vehicle, comprising:

a transmitter including;

an operation section;

a data generating section for generating transmission data formed of a fixed code, a rolling code corresponding to a number of times of operation of the operation section, and transmission information;

a modulation section for modulating the transmission data; and

a transmission section for transmitting the modulated transmission data, and

a receiver including;

a receiving section for receiving the transmission data transmitted from said transmitter;

a demodulation section for demodulating the received data; and

a data decoding section for judging, on the basis of the fixed code and the rolling code, whether data may be received,

wherein said transmitter has transmission data record means for recording transmitted transmission data,

a plurality of rolling code data storing areas for storing current rolling code data and past rolling code data being provided within said transmission data record means, and on the basis thereof, said transmitter generates transmission data, and

wherein said transmission data record means has a writing error check area for storing writing error check data which expresses whether a transmitted rolling code has been written correctly, and at said data generating section, it is judged whether rolling code data is correct on the basis of the writing error check data within said writing error check area, and on the basis of said judgment, one of current rolling code data and past rolling code data is read.

2. A transceiver for a vehicle according to claim 1, wherein, when it is judged by said judgment that the rolling code data is correct, current rolling code data is read from the rolling code data storing area, and when it is judged by said judgment that the rolling code data is incorrect, past rolling code data is read from the rolling code data storing area.

3. A transceiver for a vehicle according to claim 1, wherein said transmission data record means is an E²PROM.

4. A transmitting-receiving method of a transceiver for a vehicle comprising the steps of:

preparing a transceiver for a vehicle comprising;

a transmitter including;

an operation section;

a data generating section for generating transmission data formed of a fixed code, a rolling code corresponding to the number of times of operation of said operation section, and transmission information;

a modulation section for modulating the transmission data;

a transmission section for transmitting the modulated transmission data; and

transmission data record means having a writing error check area, for storing writing error check data expressing whether a rolling code has been written correctly, and a plurality of rolling code data storing areas, for storing current rolling code data and past rolling code data, the transmitted transmission data being written into said transmission data record means, and

a receiver including;

a receiving section for receiving the transmission data transmitted from said transmitter;

a demodulation section for demodulating the received data; and

a data decoding section for judging, on the basis of the fixed code, the rolling code, whether data may be received;

wherein the method includes the steps of;

recording transmitted transmission data into said transmission data record means;

reading the data recorded in said transmission data record means;

determining at said data generating section whether data in the writing error check area representative of a transmission rolling code was written correctly;

reading one of current rolling code data and past rolling code data on the basis of said determination;

transmitting the read data via said modulation section and said transmission section; and

receiving by said receiver, the transmitted data.

5. A transmitting-receiving method of a transceiver for a vehicle according to claim 4, wherein, when it is judged by said judgment that the data in the writing error check area has been read correctly, current rolling code data is read from the rolling code data storing data, and when it is judged by said judgment that the data in the writing error check area has been read incorrectly, past rolling code data is read from the rolling code data storing area.

6. A transmitting-receiving method of a transceiver for a vehicle according to claim 4, further comprising the steps of:

prior to said judgment, judging whether a number storing area for storing the number of a rolling code area provided at said transmission data record means is read correctly; and

on the basis of said judgment, reading one of current rolling code data and past rolling code data.

7. A transmitting-receiving method of a transceiver for a vehicle according to claim 6, wherein when it is judged the number storing area is read incorrectly, past rolling code data is read.

8. A transmitting-receiving method of a transceiver for a vehicle according to claim 4, further comprising the step of:

writing the transmitted data into said transmission data record means.