Information processing method and apparatus, automotive information system and method of controlling the same, and storage medium on which an information processing program is stored

• US 6,516,359 B1
• Filed: 04/28/1999
• Issued: 02/04/2003
• Est. Priority Date: 04/28/1998
• Status: Active Grant

• Current Assignee: Clarion Co., Ltd. (Faurecia SA)
• Original Assignee: Clarion Co., Ltd. (Faurecia SA)
• Inventors: Kurihara, Takao, Uehara, Nagatoshi, Kurihara, Nobuhiro
• Primary Examiner(s): Gaffin, Jeffrey
• Assistant Examiner(s): ELAMIN, ABDELMONIEM I
• Application Number:
  US09/301,283
• Time in Patent Office: 1,378 Days
• Field of Search: 710/52, 710/63, 710/72, 710/101, 710/129, 709/219
• US Class Current: 710/52
• CPC Class Codes: G06F 2205/061 Adapt frequency, i.e. clock frequency at one side is adapted to clock frequency, or average clock frequency, at the other side; Not pulse stuffing only
• CPC Class Codes: G06F 5/06 for changing the speed of data flow, i.e. speed regularising or timing, e.g. delay lines, FIFO buffers; over- or underrun control therefor G06F7/78 takes precedence
• CPC Class Codes: G11B 20/10 Digital recording or reproducing
• CPC Class Codes: G11B 20/10527 Audio or video recording; Data buffering arrangements G11B20/12 - G11B20/18 take precedence
• CPC Class Codes: G11B 2020/10694 output interface, i.e. the way data leave the buffer, e.g. by adjusting the clock rate
• CPC Class Codes: G11B 2020/10703 processing rate of the buffer, e.g. by accelerating the data output
• CPC Class Codes: G11B 2020/10805 involving specific measures to prevent a buffer overflow
• CPC Class Codes: G11B 27/002 Programmed access in sequence to a plurality of record carriers or indexed parts, e.g. tracks, thereof, e.g. for editing; transfer of record carriers from magazine G11B15/68, G11B17/10; G11B17/22

Abstract

An information processing apparatus having a device which processes data at a rate exactly adjusted relative to the rate of a data supplying device without requiring a common clock signal. A writing unit writes data into a buffer memory. When a first half of the buffer memory has become filled with data, a starter makes a reading unit start reading data from the buffer memory. A writing time measurement unit and a reading time measurement unit respectively measure the writing time required to write data in the buffer memory and the reading time required to read data from the buffer memory starting from the first storage location to the exact middle storage location of the buffer memory. A controller controls the rate at which data is read from the buffer memory based on the relationship between the writing time and the reading time.

Claims

1. An information processing apparatus comprising:

a buffer for storing given data;

writing means for writing data into a buffer;

reading means for reading data from the buffer;

starting means for making said reading means start reading data when data has been written into the buffer such that the first half storage area of the buffer has become filled with the data;

writing time measuring means for measuring the writing time required to write data into the buffer starting from the first storage location to the exact middle storage location of the buffer;

reading time measuring means for measuring the reading time required to read the data starting from the buffer from the first storage location to the exact middle storage location of the buffer; and

control means for controlling the rate at which data is read from the buffer, in accordance with the relationship between said writing time and said reading time.

7. An information processing apparatus according to claim 1, wherein said control means controls said rate by dividing a given clock by a divisor such that when the rate at which data is written into the buffer is lower than the rate at which data is read from the buffer, the clock is divided by a reduced divisor and the clock is divided by an increased divisor when the rate at which data is written into the buffer is higher than the rate at which data is read from the buffer.

8. An information processing apparatus according to claim 1, wherein at least one of the operation of writing data and the operation of reading data is performed by a direct memory access.

2. A method of processing information, comprising the steps of:

writing given data into a buffer;

reading data from the buffer;

starting said reading step when data has been written into the buffer until a half of the buffer has become filled with the data;

measuring the writing time required to write data into the buffer starting from the first storage location to the exact middle storage location of the buffer;

measuring the reading time required to read the data from the buffer starting from the first storage location to the exact middle storage location of the buffer; and

controlling the rate at which data is read from the buffer, in accordance with the relationship between said writing time and said reading time.

3. A method of processing information according to claim 2, wherein said control step controls said rate by dividing a given clock by a divisor such that when the rate at which data is written into the buffer is lower than the rate at which data is read from the buffer, the clock is divided by a reduced divisor but the clock is divided by an increased divisor when the rate at which data is written into the buffer is higher than the rate at which data is read from the buffer.

4. An automotive information system comprising a disk playback device for supplying audio data and a main unit for processing the audio data supplied, wherein said main unit comprises:

a buffer for storing given data;

writing means for writing audio data received from said disk playback device into the buffer;

reading means for reading audio data from the buffer;

starting means for making said reading means start reading data when audio data has been written into the buffer such that the first half storage area of the buffer has become filled with the audio data;

writing time measuring means for measuring the writing time required to write audio data into the buffer starting from the first storage location to the exact middle storage location of the buffer;

reading time measuring means for measuring the time required to read the audio data from the buffer starting from the first storage location to the exact middle storage location of the buffer; and

control means for controlling the rate at which audio data is read from the buffer, in accordance with the relationship between the said writing time and said reading time.

5. A method of controlling an automotive information system using a disk playback device for supplying audio data and a main unit for processing the audio data supplied, wherein said method performs, in said main unit, a process comprising the steps of:

writing audio data received from said disk playback device into a buffer;

reading audio data from the buffer;

starting said reading step when audio data has been written into the buffer such that the first half storage area of the buffer has become filled with the audio data;

measuring the writing time required to write audio data into the buffer starting from the first storage location to the exact middle storage location of the buffer;

measuring the reading time required to read the audio data from the buffer starting from the first storage location to the exact middle storage location of the buffer; and

controlling the rate at which audio data is read from the buffer, in accordance with the relationship between said writing time and said reading time.

6. A storage medium on which an information processing program used by a computer to perform an information process is stored, said information process comprising the steps of:

writing given data into a buffer;

starting reading data from the buffer when data has been written into the buffer such that the first half storage area of the buffer has become filled with the data;

measuring the writing time required to write data into the buffer starting from the first storage location to the exact middle storage location of the buffer;

measuring the reading time required to read the data from the buffer starting from the first storage location to the exact middle storage location of the buffer; and

controlling the rate at which data is read from the buffer, in accordance with the relationship between said writing time and said reading time.