JP3740692B2 - Disc player - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a disc playback apparatus on which a microcomputer and a digital signal processor (DSP) for servo control having a program code area of a RAM version or a ROM version are mounted, and in particular, a recent DVD (digital video). It is used for digital video reproduction equipment represented by disc) and digital sound reproduction equipment represented by CD (compact disc).
[0002]
[Prior art]
Recently, a disk playback device such as a DVD on which a microcomputer and a servo-controlled digital signal processor having a RAM or ROM program code area are mounted is becoming widespread.
[0003]
Such a disk playback device is basically equipped with a ROM version of a digital signal processor in which a servo control program is written in advance. However, in consideration of the production plan of the disk playback device, the ROM version of the digital signal processor is used. The production of the processor may not be in time for the production of the disk playback device. In that case, until the production of the ROM version of the digital signal processor catches up, the disk playback device is equipped with the RAM version of the digital signal processor. A program code for servo control is transferred to the signal processor (see, for example, JP-A-5-81219). In the ROM version, since the servo control program code is written from the beginning, such a transfer is unnecessary.
[0004]
As described above, when the conventional disk reproducing apparatus is equipped with the microcomputer and the digital signal processor, the digital signal processor is a RAM version digital signal processor or a ROM version digital signal processor. There is. For this reason, when using the disk reproducing apparatus, it is necessary to determine whether the digital signal processor installed is the ROM version or the RAM version on the microcomputer side.
[0005]
Therefore, conventionally, in order to eliminate the need for such determination, a microcomputer corresponding to the ROM version of the digital signal processor and a microcomputer corresponding to the RAM version of the digital signal processor are separately prepared in advance. Depending on the type of digital signal processor to be mounted (ROM version or RAM version), a method has been adopted in which the mounted microcomputer is properly used (this is called prior art 1).
[0006]
Further, as a method for sharing the microcomputer without using such a proper use, the microcomputer is provided with a switch circuit indicating whether the mounted digital signal processor is the RAM version or the ROM version. That is, the switching (setting) of the switch circuit allows the microcomputer to determine whether the installed digital signal processor is the RAM version or the ROM version. Then, when the disk playback device is used, that is, when the power is turned on, the microcomputer determines whether the mounted digital signal processor is the RAM version or the ROM version based on the state of the switch circuit. In the case of the version, the servo control program code is transferred to the RAM version of the digital signal processor (this is called prior art 2).
[0007]
[Problems to be solved by the invention]
However, the method of the prior art 1 described above has a problem in that the cost is high because the RAM version microcomputer and the ROM version microcomputer need to be created separately.
[0008]
Further, although the method of the above-described prior art 2 reduces the cost as much as the microcomputer can be used in common, there is a problem in that this causes a high cost because it is necessary to newly provide a switch circuit. In addition, since this switch circuit needs to be manually set by an operator, there is a problem that a setting error may occur.
[0009]
The present invention was devised to solve such problems, and its purpose is to determine whether the installed digital signal processor is a RAM version by software processing such as checking the presence or absence of a response to a response command. It is an object of the present invention to provide a disk reproducing apparatus capable of reducing costs by determining whether a version is a version or not, and reliably determining whether a version is a RAM version or a ROM version.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a disk reproducing apparatus according to the present invention is a disk reproducing apparatus in which a microcomputer and a digital signal processor for servo control having a RAM or ROM program code area are mounted. In the program code area of the digital signal processor, a program that responds to a response command from the microcomputer is stored in advance, and when the power is turned on, the microcomputer resets the digital signal processor and outputs the response command. After issuing, it is determined whether or not a certain time has elapsed, and if there is a response from the digital signal processor before the certain time has elapsed, it is determined that the digital signal processor is a ROM version digital signal processor. Shi If no response is received from the digital signal processor after the predetermined time has elapsed, it is determined that the digital signal processor is a RAM version of the digital signal processor, and a program code is transmitted to the RAM version of the digital signal processor. It is characterized by transferring.
[0011]
According to the present invention having such characteristics, a program that responds to a response command from a microcomputer is stored in advance in the program code area of the ROM version of the digital signal processor. When the power is turned on, the microcomputer resets the digital signal processor, issues a response command to the digital signal processor, and then determines whether or not a certain time has elapsed.
[0012]
If there is a response from the digital signal processor before the predetermined time has elapsed, it is determined that the digital signal processor is a ROM version digital signal processor.
[0013]
On the other hand, if there is no response from the digital signal processor even after a predetermined time has elapsed, the digital signal processor determines that the digital signal processor is a RAM version in which nothing is written in the program code area. In this case, the servo control program code is transferred to the RAM version of the digital signal processor.
[0014]
As described above, according to the present invention, the program code area of the ROM version of the digital signal processor is mounted with only a very simple process of storing a program responding to a response command from the microcomputer in advance. It is possible to reliably determine whether the digital signal processor is the RAM version or the ROM version. In addition, since the microcomputer can be made common regardless of whether the digital signal processor is the RAM version or the ROM version, it is possible to reduce the effort for creating a mask for the microcomputer. Further, since it is not necessary to provide a switch circuit as in the above-described prior art 2, a substrate can be formed in the same process regardless of the RAM version and the ROM version.
[0015]
The disk reproducing apparatus of the present invention is a disk reproducing apparatus in which a microcomputer and a servo control digital signal processor having a RAM or ROM version program code area are mounted. In the program code area, a program that responds to a response command from the microcomputer is stored in advance. When the power is turned on, the microcomputer issues a response command to the digital signal processor. If there is a response from the digital signal processor, it is determined that the digital signal processor is a ROM version of the digital signal processor. If there is no response, the digital signal processor And judging that the AM version of digital signal processors.
[0016]
According to the present invention having such characteristics, a program that responds to a response command from a microcomputer is stored in advance in the program code area of the ROM version of the digital signal processor. When the power is turned on, the microcomputer issues a response command to the digital signal processor. If there is a response from the digital signal processor, it is determined that the digital signal processor is a ROM version digital signal processor. If there is no response from the digital signal processor, the digital signal processor It is determined that the digital signal processor is a RAM version to which nothing is written.
[0017]
As described above, according to the present invention, the program code area of the ROM version of the digital signal processor is mounted with only a very simple process of storing a program responding to a response command from the microcomputer in advance. It is possible to reliably determine whether the digital signal processor is the RAM version or the ROM version. In addition, since the microcomputer can be made common regardless of whether the digital signal processor is the RAM version or the ROM version, it is possible to reduce the effort for creating a mask for the microcomputer. Further, since it is not necessary to provide a switch circuit as in the above-described prior art 2, a substrate can be formed in the same process regardless of the RAM version and the ROM version.
[0018]
According to the disk reproducing apparatus of the present invention, in the disk reproducing apparatus equipped with a microcomputer and a digital signal processor for servo control having a program code area of RAM version or ROM version, the ROM version digital signal is provided. In the program code area of the processor, a program that responds to a response command from the microcomputer is stored in advance, and when the power is turned on, the microcomputer checks whether or not a certain time has elapsed after issuing the response command. If a response is received from the digital signal processor before a predetermined time elapses, it is determined that the digital signal processor is a ROM version digital signal processor, and the digital signal processor From signal processor If the answer was not, characterized in that the digital signal processor is determined to be a digital signal processor RAM version.
[0019]
According to the present invention having such characteristics, a program that responds to a response command from a microcomputer is stored in advance in the program code area of the ROM version of the digital signal processor. When the power is turned on, the microcomputer resets the digital signal processor, issues a response command to the digital signal processor, and then determines whether or not a certain time has elapsed.
[0020]
If there is a response from the digital signal processor before the predetermined time has elapsed, it is determined that the digital signal processor is a ROM version digital signal processor.
[0021]
On the other hand, if there is no response from the digital signal processor even after a predetermined time has elapsed, the digital signal processor determines that the digital signal processor is a RAM version in which nothing is written in the program code area.
[0022]
As described above, according to the present invention, the program code area of the ROM version of the digital signal processor is mounted with only a very simple process of storing a program responding to a response command from the microcomputer in advance. It is possible to reliably determine whether the digital signal processor is the RAM version or the ROM version. In addition, since the microcomputer can be made common regardless of whether the digital signal processor is the RAM version or the ROM version, it is possible to reduce the effort for creating a mask for the microcomputer. Further, since it is not necessary to provide a switch circuit as in the above-described prior art 2, a substrate can be formed in the same process regardless of the RAM version and the ROM version.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a circuit block diagram showing an embodiment in which a disc playback apparatus of the present invention is applied to a DVD digital video playback apparatus.
[0024]
The output of the pickup 3 that detects information from the disk 1 that is rotationally driven by the disk motor 2 is guided to the signal processing circuit 5 and the servo processing circuit 6 via the RF amplifier 4, and the output of the servo processing circuit 6 is It is led to a digital signal processor (hereinafter abbreviated as DSP) 5. The DSP 5 is connected to a track buffer RAM 7 for temporarily storing data (here, compressed by MPEG (Motion Picture Expert Group)) amplified by the RF amplifier 4 and decoded according to the DVD standard. . These RF amplifier 4, DSP 5 and servo processing circuit 6 are controlled by a microcomputer 8 which is a front end CPU.
[0025]
The servo processing circuit 6 performs focusing servo and tracking servo control for the pickup 3 in accordance with commands and control data transmitted / received from the microcomputer 8 via the DSP 5 and moves the entire pickup 3 in the radial direction of the disk 1. The sled motor 9 is controlled to control the tray motor 10 that drives a tray (not shown) on which the disk 1 is loaded. The reproduction signal when the disc 1 loaded in the tray is a DVD is input to the DSP 5 via the RF amplifier 4, and the reproduction signal when the disc 1 loaded in the tray is a CD-ROM is The signal is input from the RF amplifier 4 to the DSP 5 via the servo processing circuit 6. The DSP 5 also performs such DVD data decoding processing, CD-ROM data decoding processing, and the like.
[0026]
The DSP 5 is connected to an A / V (Audio / Video) decoder 11, and the output of the A / V decoder 11 is a video encoder 13 having video output terminals 13a and 13b and a D having an audio output terminal 14a. / A converter 14 is connected. The A / V decoder 11 expands the data compressed by MPEG read from the track buffer RAM 7. The A / V decoder 11 is connected to an A / V decoding RAM 15 for storing decompressed digital data for several screens.
[0027]
The A / V decoder 11 is connected to a back-end CPU 16, and a work RAM 17 is connected to the back-end CPU 16.
Further, a front panel controller 19 that performs display control of the front panel 20 such as an LCD is connected to the back-end CPU 16, and the output of the key input unit 21 is guided to the front panel controller 19. The front panel controller 19 is provided with a receiving unit (not shown) that receives a transmission signal from the remote controller 22.
[0028]
Here, the operation at the time of reproduction in the digital video reproduction apparatus having the above configuration will be briefly described.
Data recorded on the disk 1 is detected by the pickup 3, waveform shaping and amplification are performed by the RF amplifier 4, and then decoded by the DSP 5 in accordance with the DVD standard. The decoded data is sequentially stored in the track buffer RAM 7 while being compressed by MPEG, and waits for a read request from the back-end CPU 16.
[0029]
The data stored in the track buffer RAM 7 is sequentially read in accordance with a read request from the back-end CPU 16 and transferred to the A / V decoder 11 where the compressed data is expanded by MPEG and converted into video data. Decoded. The decoded video data is temporarily stored in the A / V decoding RAM 15, then read out again and sequentially transferred to the video encoder 13, where it is converted into an analog video signal and output from the video output terminals 13a and 13b. Is done.
[0030]
On the other hand, audio data compressed by MPEG is sequentially stored in the track buffer RAM 7 in the same manner as video data, sequentially read in accordance with a read request from the back-end CPU 16 and transferred to the D / A converter 14. Then, the compressed data is decompressed by MPEG and decoded into audio data. The decoded audio data is temporarily stored in the A / V decoding RAM 15, then read out again and sequentially transferred to the D / A converter 14, where it is converted into an analog audio signal and output from the audio output terminal 14a. Is done.
[0031]
In such a reproduction operation process, the data stored in the track buffer RAM 7 is sequentially overwritten by the next data when sequentially read in accordance with the read request from the back-end CPU 16, and the image data is sequentially converted to the subsequent data by repeating this. It is output to the signal reproduction system. The same applies to the A / V decode RAM 15. When the data stored in the A / V decode RAM 15 is sequentially read in accordance with a read request from the back-end CPU 16, the next read and transferred from the track buffer RAM 7 is performed. The image data is sequentially overwritten by the data, and the image data is sequentially output to the subsequent signal reproduction system by repeating this.
[0032]
In a digital video reproduction apparatus that performs such a reproduction operation, the DSP 5 installed in principle is equipped with a ROM version DSP 5 in which a servo control program has been written in advance. The RAM version DSP 5 is installed at the time of production of the playback device, and when the power is turned on, the servo control program code is transferred from the microcomputer 8 to the RAM version DSP 5 and the servo control program is transferred to the RAM version DSP 5. May be stored. The subsequent exchange of commands and control data between the microcomputer 8 and the DSP 5 is the same for both the ROM version DSP 5 and the RAM version DSP 5.
Therefore, in the digital video reproduction apparatus, it is necessary to determine whether the DSP 5 installed is the RAM version or the ROM version when the power is turned on.
[0033]
Therefore, in the digital video reproduction apparatus of the present embodiment, a program that responds to a response command from the microcomputer 8 is stored in advance in the program code area of the ROM version DSP 5. When the power is turned on, the microcomputer 8 resets the DSP 5 and issues a response command. If the DSP 5 responds to the response command, the installed DSP 5 is a ROM version DSP. If there is no response, it is determined that the installed DSP 5 is a RAM version DSP.
[0034]
FIG. 2 is an explanatory diagram showing in detail the connection between the microcomputer 8 and the DSP 5.
The microcomputer 8 and the DSP 5 are connected to each other by a data bus 31 that transmits / receives 8-bit parallel data, an address bus 32, and a signal line 33 that transmits a HINT signal. The DSP 5 is provided with four registers (write registers) 51 for writing and four registers (status registers) 52 for reading. The DSP 5 stores a program for responding to a response command from the microcomputer 8.
[0035]
That is, when the microcomputer 8 writes a code of “5Dh” (hexadecimal), for example, which is a response command through the data bus 31, to the write register 51 of the DSP 5, the DSP 5 detects this and sends a response command to the status register 52. The same “5Dh” is written as response data, and then the HINT signal is set to the “L” level. The microcomputer 8 detects that the HINT signal has become “L” level, and reads the response data “5Dh” written in the status register 52 of the DSP 5. When the same response data as the response command is returned, it is determined that the DSP 5 is a ROM version DSP.
[0036]
On the other hand, in the case of the RAM version DSP5, even if a response command is written to the write register 51 through the data bus 31, the DSP5 does not write response data to the status register 52 (there is no such processing program). Therefore, response data is not returned to the microcomputer 8. Therefore, the microcomputer 8 can determine that the DSP 5 is a RAM version DSP because no response data is returned even if a response command is transmitted.
[0037]
Next, the determination process of the DSP 5 by the microcomputer 8 will be described in more detail with reference to the flowcharts shown in FIGS. 3 shows processing on the microcomputer 8 side, and FIG. 4 shows processing on the DSP 5 side which is a ROM version.
[0038]
When the power is turned on, the microcomputer 8 resets the DSP 5 (step S1) and issues a response command “5Dh” to the DSP 5 (step S2). Then, it is determined whether the DSP 5 has set response data (step S3). At this time, the microcomputer 8 starts a timer circuit (not shown) and starts measurement for a predetermined time (step S4). That is, after issuing the response command, it is determined whether or not the DSP 5 has set response data for a certain period of time.
[0039]
On the other hand, the ROM version DSP 5 is in a waiting state for receiving various commands from the microcomputer 8 (step S11), and when a command is received (when it is determined Yes in step S11), the received command is received. It is determined whether or not the command (that is, the command written in the write register 51) is a response command (step S12). As a result, if it is a response command (when it is determined YES in step S12), the same “5Dh” as the response command is written in the status register 52 as response data (step S13), and then the HINT signal is “ L ”level (step S14). On the other hand, when the received command is not a response command (when it is determined No in step S12), processing corresponding to the command is executed (step S15).
[0040]
On the other hand, after issuing the response command, the microcomputer 8 determines whether or not a certain time has elapsed (repetition of steps S3 and S4), and if there is a response from the DSP 5 before the certain time has elapsed (HINT When it is detected that the signal has become “L” level (when it is determined Yes in step S3), the response data “5Dh” written in the status register 52 of the DSP 5 is read (step S5). ). Then, it is determined whether or not the acquired response data is response data corresponding to the issued response command (step S6). If the response data is response data corresponding to the response command (Yes in step S6) ) Determines that the installed DSP 5 is a ROM version DSP (step S7). That is, since the servo control program has already been written in the DSP 5, the microcomputer 8 continues the disk reproduction process as usual.
[0041]
On the other hand, in step S3 and step S4, if there is no response from the DSP 5 even if a predetermined time has passed (if the HINT signal has not become "L" level) (No in step S3, Yes in step S4). If it is determined, it is determined that the installed DSP 5 is a RAM DSP (step S8), and a servo control program code is transferred to the RAM DSP 5 (step S9). As a result, the servo control program code is written in the DSP 5 in the same manner as in the ROM version of the DSP 5, so that the microcomputer 8 subsequently executes the disk reproduction process as usual.
[0042]
【The invention's effect】
According to the disk reproducing apparatus of the present invention, it is mounted by a very simple process such as storing a program responding to a response command from a microcomputer in advance in a program code area of a ROM version of a digital signal processor. It is possible to reliably determine whether the digital signal processor is the RAM version or the ROM version. In addition, since the microcomputer can be made common regardless of whether the digital signal processor is the RAM version or the ROM version, it is possible to reduce the effort for creating a mask for the microcomputer. Further, since there is no need to provide a switch circuit as in the prior art, a substrate on which a microcomputer and a digital signal processor are mounted can be produced in the same process regardless of the RAM version and the ROM version.
[Brief description of the drawings]
FIG. 1 is a circuit block diagram showing an embodiment in which a disc playback apparatus of the present invention is applied to a digital video playback apparatus for DVD.
FIG. 2 is an explanatory diagram showing in detail the connection between a microcomputer and a DSP.
FIG. 3 is a flowchart showing processing on the microcomputer side for explaining DSP determination processing by the microcomputer;
FIG. 4 is a flowchart showing processing on the DSP side for explaining DSP determination processing by the microcomputer;
[Explanation of symbols]
1 disc
5 DSP (Digital Signal Processor)
6 Servo processing circuit
8 Microcomputer (front-end CPU)
16 Backend CPU
19 Front panel controller
20 Front panel
21 Key input section
22 Remote control

Claims (3)

In a disk reproducing apparatus equipped with a microcomputer and a digital signal processor for servo control having a program code area of RAM version or ROM version,
In the program code area of the ROM version of the digital signal processor, a program that responds to a response command from the microcomputer is stored in advance.
When the power is turned on, the microcomputer resets the digital signal processor, issues a response command, determines whether a certain time has elapsed, and receives a response from the digital signal processor before the certain time elapses. If there is a response, the digital signal processor is determined to be a ROM version of the digital signal processor. A disc reproducing apparatus characterized by determining that the digital signal processor is a version and transferring a program code to the digital signal processor of a RAM version. In a disk reproducing apparatus equipped with a microcomputer and a digital signal processor for servo control having a program code area of RAM version or ROM version,
In the program code area of the ROM version of the digital signal processor, a program that responds to a response command from the microcomputer is stored in advance.
When the power is turned on, the microcomputer issues a response command to the digital signal processor. If there is a response from the digital signal processor to the response command, the digital signal processor A disc reproducing apparatus, characterized in that it is determined that the signal processor is a signal processor, and if the response is not received, the digital signal processor is determined to be a RAM version digital signal processor. In a disk reproducing apparatus equipped with a microcomputer and a digital signal processor for servo control having a program code area of RAM version or ROM version,
In the program code area of the ROM version of the digital signal processor, a program that responds to a response command from the microcomputer is stored in advance.
When the power is turned on, the microcomputer determines whether or not a certain time has elapsed after issuing the response command, and if there is a response from the digital signal processor before the certain time has elapsed, the digital signal If it is determined that the processor is a ROM version digital signal processor and no response is received from the digital signal processor even after the predetermined time has elapsed, it is determined that the digital signal processor is a RAM version digital signal processor. And a disc reproducing apparatus.

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