Data processing system

Abstract

The present invention easily realizes synchronization between processor cores in a multicore system. A data processing system receiving a group of data of different kinds from the outside and performing data processes by kinds includes: a plurality of data process control units corresponding to the kinds of the data group and performing data processes on the data group of corresponding kinds; and a memory unit which can be accessed by the data process control units and has a first region storing a value indicating whether the data process by the data process control units can be executed or not. Each of the data process control units updates the value in the first region on completion of preparation for executing the data process of itself and, when the value in the first region becomes a predetermined value, synchronizes start timings of the data processes and executes the data processes.

What is claimed is: 
     
         1 . A data processing system for receiving contents including a video stream and an audio stream, processing data of contents and outputting results of data process, comprising:
 a video processing unit configured to process data of the video stream;   an audio processing unit configured to process data of the audio stream;   a memory unit configured to be accessed by the video processing unit and the audio processing unit and, having a first information storing a value controlling execution of data process;   a display unit configured to output a result of data process of the video stream; and   an audio outputting unit configured to output a result of data process of the audio data stream,   wherein each of the video processing unit and the audio processing unit updates the first information on completion of preparation for executing the data process of itself and,   wherein the video processing unit and the audio processing unit start at the same time when the first information becomes a predetermined value.   
     
     
         2 . The data processing system according to  claim 1 ,
 the video processing unit further comprising:
 a first reference clock generation unit configured to generate a first reference time expressing lapse time since start of the data process based on a first operation clock supplied to itself; and 
 a first control unit configured to update the first information and to store the first reference time in the memory unit, 
   the audio processing unit further comprising:
 a second reference clock generation unit configured to generate a second reference time expressing lapse time since start of the data process based on a second operation clock supplied to itself; and 
 a second control unit configured to update the first information and to store the second reference time in the memory unit, 
   wherein the first control unit is configured to start the first reference clock generation unit on confirmation that the first information becomes the predetermined value,   wherein the second control unit is configured to start the second reference clock generation unit on confirmation that the first information becomes the predetermined value.   
     
     
         3 . The data processing unit according to  claim 2 ,
 wherein each of the video stream and audio stream has a plurality of frames and one frame is a unit of data process,   wherein each of frames includes video data or audio data, and time information instructing a timing of outputting a result of data process,   the video processing unit further comprising:
 a first data processing unit configured to start the video data process by instructing from the first control unit, and output the result of data process of video data to the display unit, 
   the audio processing unit further comprising:
 a second data processing unit configured to start the audio data process by instructing from the second control unit, and output the result of data process of audio data to the audio outputting unit. 
   
     
     
         4 . The data processing system according to  claim 3 ,
 wherein the first control unit is configured to read the first reference time and the second reference time stored in the memory unit and calculate a first adjusting time from the first reference time and the second reference time,   wherein the first data processing unit is configured to adjust the timing of starting the data processes based on the first adjusting time.   
     
     
         5 . The data processing system according to  claim 3 ,
 wherein the first control unit is configured to read the first reference time and the second reference time stored in the memory unit and calculate a first adjusting time from the first reference time and the second reference time,   wherein the first data processing unit is configured to adjust the timing to output to the display unit based on the first adjusting time.   
     
     
         6 . The data processing system according to  claim 3 ,
 wherein the second control unit is configured to read the first reference time and the second reference time stored in the memory unit and calculate a second adjusting time from the first reference time and the second reference time,   wherein the second data processing unit is configured to adjust the timing of starting the data processes based on the second adjusting time.   
     
     
         7 . The data processing system according to  claim 3 ,
 wherein the second control unit is configured to read the first reference time and the second reference time stored in the memory unit and calculate a second adjusting time from the first reference time and the second reference time,   wherein the second data processing unit is configured to adjust the timing to output to the audio output unit based on the second adjusting time.   
     
     
         8 . The data processing system according to  claim 1 ,
 wherein an initial value of the first information is set according to the number of the video processing unit and the audio processing unit,   wherein each of the first control unit and the second processing unit controller is configured to update the first information by decrementing on completion of preparation for executing the data process of itself, and   wherein the predetermined value is a value indicative of zero.   
     
     
         9 . The data processing system according to  claim 1 ,
 wherein each of the first control unit and the second control unit is configured to update the count value by incrementing from the predetermined value in the case of stopping execution of its data processing.   
     
     
         10 . The data processing system according to  claim 2 ,
 wherein the first reference time and the second reference time are values counted every time which is based on a least common multiple of time of one cycle of the first operation clock and time of one cycle of the second operation reference clock.