JP2004334578A - Optical disk device and optical disk interface system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance reliability by controlling strobe signals coming from an optical disk device when data are transferred from the optical disk device to a host computer. <P>SOLUTION: An optical disk interface system includes an optical disk device and a host computer connected to the optical disk device. The host computer has a CRC code generating means. The optical disk device has a means for transferring test data to the host computer; a means for generating strobe signals in such a way that the signals rise or fall at different minute time intervals with respect to the test data; a means for comparing a CRC code coming from the CRC code generating means of the host computer to a CRC code generated within the optical disk device to detect whether the transfer of the data to the host computer is normal or not; and a strobe signal control means which selects the appropriate strobe signal based on a plurality of signals generated by the detection means. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００１８】
以下では、光ディスク装置２から出力されるデータに対して、ストローブの位置を変更して、それらに対応したＣＲＣコードをホストコンピュータで生成し、それを基にストローブ信号を制御する実施の形態を示す。
【００１９】
≪第１の実施の形態≫
図３に示される第１の実施の形態では、光ディスク装置２から出力されるデータに対して、ストローブの位置を光ディスク装置２側で変更する。
【００２０】
第１の実施の形態では、通常のデータを転送する前に、図４のようなデータ転送が試験的に行なわれる。ＤＤ［１５：０］は内部クロック（ｃｌｋ）に同期化している。従って、図４の（１）の区間に何クロック分含まれるかが決まる。この図４の場合では、５クロック分である。よって、内部クロックに同期化するストローブ信号を（１）の区間で生成できる数がストローブカウンタ３０で決定できる。図４の場合には、Ａ〜Ｊの１０種ということになる。
【００２１】
まず、ストローブを図４の「Ａ」の早いタイミングとして、ホストコンピュータ２０に転送する。そして、ホストコンピュータ２０のＣＲＣ生成回路３８でＣＲＣコードを生成し、そのＣＲＣコードを光ディスク装置２に返す。ホストコンピュータ２０から送られてきたＣＲＣコードと、予め光ディスク装置２側で生成されているＣＲＣコードとをＣＲＣ比較回路３２にて比較し、一致していればＣＲＣＯＫ［０］のビットを“１”にし、不一致であればＣＲＣＮＧ［０］のビットを“１”にする。図４の場合ストローブが１０種あるので、ＣＲＣＯＫ、ＣＲＣＮＧは１０ビットのバス幅となる。
【００２２】
次に、ストローブカウンタ３０が１カウントし、ストローブを図４の「Ｂ」のタイミングでホストコンピュータ２０に転送する。そして、上記と同様に、光ディスク装置２のＣＲＣ比較回路３２でＯＫ／ＮＧの判断をし、その結果をＣＲＣＯＫ［１］／ＣＲＣＮＧ［１］ビットで表す。
【００２３】
その後同様に、図４の「Ｃ」、「Ｄ」、「Ｅ」、「Ｆ」、「Ｇ」、「Ｈ」、「Ｉ」及び「Ｊ」のタイミングまでストローブをホストコンピュータ２０に転送し、生成されるＣＲＣコードの比較をする。その結果をＣＲＣＯＫ［２］〜［９］／ＣＲＣＮＧ［２］〜［９］で表す。
【００２４】
例えば、ＣＲＣＯＫ［９：０］が、
０ ０ ０ ０ １ １ １ １ １ ０
となっていたなら、ストローブ制御回路２８により、連続して“１”となっている点の中間点である「Ｇ」のストローブ信号が最適であるという判断がなされる。そして、「Ｇ」のストローブを選択するというストローブの制御が行なわれる。
【００２５】
以上のように、ＣＲＣＯＫ［９：０］の１０ビットの中で、連続して”１”となっている点の中間点をデバイス側のストローブ制御回路２８で検出することにより、最適なストローブを見つけることができる。
【００２６】
ところで、図３の第１の実施形態では、通常のデータ転送と試験的なデータ転送とを区別するために、ＣＲＣ比較回路３２から出力するＮＧビットが設けられている。このＮＧビットは、通常のデータ転送でＣＲＣエラーのときに“１”となるもので、その先にあるセレクタ３４、３６を制御する。通常のデータ転送のときは、これらのセレクタ３４、３６は“０”が選択される。よって、このとき、ＤＲＡＭ１６からのデータに対して、光ディスク装置２側とホストコンピュータ側２０との夫々にてＣＲＣを生成して、ＣＲＣ比較回路３２で比較することになる。
【００２７】
通常のデータ転送でＣＲＣエラー（即ち、ＮＧビットが“１”）であるときは図５に示すフローチャートの流れのようになる。データ転送（ステップＳ０２）にてＮＧビットが“１”になると（ステップＳ０４）、図３のセレクタ３４、３６は“１”が選択される。このとき、データ生成回路２２から試験的なデータがＤＤ［１５：０］としてホストコンピュータ２０に出力される（ステップＳ０６）。
【００２８】
その試験的データの開始により、ストローブカウンタ３０がストローブの位置を図４のようにカウントする。そのカウントに応じてストローブ制御回路２８から図４の「Ａ」のタイミングにてストローブをホストコンピュータ２０に出力する（ステップＳ０６）。そして、図４の「Ａ」のタイミングのストローブでのＣＲＣを、光ディスク装置２側とホストコンピュータ２０側とで生成し（ステップＳ１０）、ＣＲＣ比較回路３２にてＣＲＣ比較を行なう（ステップＳ１２）。その後、ＣＲＣＯＫ／ＣＲＣＮＧをストローブ制御回路２８に出力する。
【００２９】
以降、図４のＢ〜Ｊに係るストローブについても（ステップＳ０８）、同様な動作でＣＲＣが比較される。それらの比較結果を受けて、ストローブ制御回路２８が最適なストローブの位置を判断してストローブ生成回路２６に伝える。ストローブカウンタ３０からＣＲＣ比較器３２に出力されている信号は、図４のＪまでカウントし終わったら、ＮＧビットをクリア（“０”と）する（ステップＳ１６）。以上のことにより、ストローブ生成回路２６は最適なストローブを発信し、よって、最適な状態でデータ転送が行なわれる。
【００３０】
図４で示した例では、ストローブ信号を内部クロックに同期化させたが、更に細かくストローブを割り当てることもあり得る。このときは、内部クロックに非同期で（１）の区間に種々の間隔でストローブが立てられることになる。この場合も、ＣＲＣＯＫ／ＣＲＣＮＧとして、ストローブを立てる数（ＣＲＣコードを生成する回数）だけのレジスタが確保されねばならない。
【００３１】
≪第２の実施の形態≫
図６に示される第２の実施の形態では、光ディスク装置２から出力されるデータに対して、ストローブの位置をホストコンピュータ２０側で変更する。
【００３２】
第２の実施の形態に係る機構では、第１の実施の形態のようなデータ転送が試験的に行なわれる、ということはなく、該機構は通常のデータの転送において稼動する。まず、ＤＤ［１５：０］は内部クロック（ｃｌｋ）に同期化している。従って、図４の（１）の区間に何クロック分含まれるかが決まる。図４の場合では、５クロック分である。
【００３３】
ホストコンピュータ２０側では、光ディスク装置２の内部クロックと同様のクロックを生成させる。そのホストコンピュータ２０側のクロックに同期化するストローブ信号を図４（１）の区間で生成できる数がストローブカウンタ４０で決定できる。Ａ〜Ｊの１０種となる。
【００３４】
第２の実施の形態では、ホストコンピュータ２０のストローブカウンタ４０によってストローブを生成する。このストローブ生成は通常のデータ転送に対して行われるため、光ディスク装置２からは第１の実施の形態のように、何度も試験的にデータ転送をする必要がない。
【００３５】
最初に、ストローブがＡの点にあるときにＣＲＣコードを生成し、それを光ディスク装置２に返す。光ディスク装置２では、ホストコンピュータ２０から返されてきたＣＲＣコードと、予め光ディスク装置２側で生成されているＣＲＣコードとをＣＲＣ比較回路３２にて比較し、一致していればＣＲＣＯＫ［０］のビットを“１”にし、不一致であればＣＲＣＮＧ［０］のビットを“１”にする。ストローブが１０種あるので、ＣＲＣＯＫ、ＣＲＣＮＧは１０ビットのバス幅となる。
【００３６】
ストローブがＡの点にあるときにＣＲＣコードを生成してから、その後連続してＢ〜Ｊ点までのストローブについてホストコンピュータ２のＣＲＣ生成回路３８でＣＲＣを生成し、連続して光ディスク装置２に返す。そして、上記と同様に、光ディスク装置２のＣＲＣ比較回路３２で、連続してＯＫ／ＮＧの判断をし、その結果をＣＲＣＯＫ［１］〜［９］／ＣＲＣＮＧ［１］〜［９］で表す。
【００３７】
例えば、ＣＲＣＯＫ［９：０］が、
０ ０ ０ ０ １ １ １ １ １ ０
となっていたなら、ストローブ制御回路２８により、連続して“１”となっている点の中間点である「Ｇ」のストローブ信号が最適であるという判断がなされる。そして、「Ｇ」のストローブを選択するというストローブの制御が行なわれる。
【００３８】
この場合、Ｇ点はＡ点の３クロック後であるので、光ディスク装置２側から出力したストローブ信号の３クロック後の点が最適なストローブの位置となる。
【００３９】
ところで、図６の第２の実施形態においても、ＣＲＣ比較回路３２はＮＧビットを出力する。図７は、データ転送からＮＧビット確認・利用までのフローチャートである。ＤＲＡＭ１６からのデータをリードする（読み取る）とき、光ディスク装置２側とホストコンピュータ２０側とでそれぞれＣＲＣが生成され、ＣＲＣ比較回路３２で比較される。データ転送がうまくいっているとき（即ち、ＣＲＣ比較回路３２で差異が無いとき）は、ＮＧビットは“０”のままである。ＮＧビットが“０”のときは、光ディスク装置２のストローブ生成回路２６は、ストローブ制御回路２８からのストローブ位置を参照しない。よって、ホストコンピュータ２０は、そのままリード（読み取り）を継続する。
【００４０】
データ転送でエラーが生じたとき（即ち、ＣＲＣ比較回路３２で差異が生じたとき）は、ＮＧビットが“１”となり、データ転送中に予め決定しているストローブの位置がストローブ制御回路２８からストローブ生成回路２６に伝えられ、ストローブを制御する（図７・ステップＳ６２）。
【００４１】
最適なストローブ位置を予め決めておくために、転送するデータ（ステップ５２）に関して、ストローブカウンタ４０で連続するストローブ位置を決め（例えば、図４のＡ〜Ｊ）、ホストコンピュータ２０側のストローブ生成回路４２でそれぞれのストローブ位置に対してストローブ生成し（ステップＳ５４）、それぞれに付きＣＲＣを発行して光ディスク装置２側で比較しておき（ステップＳ５６）、最適なストローブ位置を決めておく（ステップＳ５８）。
【００４２】
ＮＧビットが“１”になるとストローブ制御回路２８から最適なストローブがストローブ生成回路２６に伝えられ、その後ＮＧビットはクリアされる（ステップＳ６２）。
【００４３】
第２の実施の形態の説明においても、ストローブ信号を内部クロックに同期化させたが、更に細かくストローブを割り当てることもあり得る。このときは、ホストコンピュータ２０のクロックに非同期で（１）の区間に種々の間隔でストローブが立てられることになる。この場合も、ＣＲＣＯＫ／ＣＲＣＮＧとして、ストローブを立てる数（ＣＲＣコードを生成する回数）だけのレジスタが確保されねばならない。
【００４４】
第１の実施の形態では、光ディスク装置２側がストローブを変化させるため、その都度ホストコンピュータ２０にストローブを転送しなければならないのに対して、第２の実施の形態では、ホストコンピュータ２０側がストローブを変化させるため、第１の実施の形態に比べると制御時間が短くて済み、更にデータ転送中でもストローブの制御を行なうことができる。
【００４５】
【発明の効果】
本発明を利用することにより、以下のような効果を得ることができる。
【００４６】
光ディスク装置からホストコンピュータにデータを転送する際に、ストローブの位置を最適化することで、転送の信頼性が向上する。
【００４７】
更に、光ディスク装置からホストコンピュータにデータを転送する際に、ホストコンピュータ側でストローブタイミングを変化させることも可能であるため、試験的なデータ転送をすることなく、本来のデータ転送中にホストコンピュータ側でストローブの位置を最適化することができ、よって、短時間で最適なストローブ制御をすることができる。
【図面の簡単な説明】
【図１】光ディスク装置からホストコンピュータに送られるデータとストローブ信号を示す模式図である。
【図２】光ディスク装置から出力されるデータとストローブ信号とのタイミングチャートの例である。
【図３】本発明の第１の実施の形態に係る光ディスク装置及びホストコンピュータにおける回路のブロック図である。
【図４】本発明に係るストローブ信号の発生のパターンである。
【図５】本発明の第１の実施の形態に係る動作のフローチャートの例である。
【図６】本発明の第２の実施の形態に係る光ディスク装置及びホストコンピュータにおける回路のブロック図である。
【図７】本発明の第２の実施の形態に係る動作のフローチャートの例である。
【図８】一般的な光ディスク装置のブロック図である。
【符号の説明】
２・・・光ディスク装置、１０・・・ＣＰＵ、１６・・・ＤＲＡＭ、１８・・・ＡＴＡＰＩインターフェース部、２０・・・ホストコンピュータ。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical disk device having a CRC check function.
[0002]
[Prior art]
FIG. 8 is a block diagram of a general optical disk device 2. The optical disk device 2 includes a spindle motor 4 for rotating an optical disk, a laser pickup 6, and a signal processing system. Further, the signal processing system includes an RF system for converting a detected signal into digital data, a servo system for controlling the rotation of the motor and the position of the pickup, and a digital data processing system (specifically, the DSP 8 and the CPU 10). including. Since the RF system unit and the servo system unit process analog signals, these units are generally called an analog front end (AFE) 12. The AFE 12 includes a preamplifier for amplifying a small signal detected by the pickup, a gain control, a laser output control circuit, and a servo system error detection circuit.
[0003]
When reading (reading) a medium such as a CD (compact disk), the data read by the laser pickup 6 is subjected to analog signal processing by the AFE 12, and the RF signal from the AFE 12 is processed by the DSP 8 to digital data. Thereafter, the data is subjected to signal processing (for example, error correction / detection, etc.) by various main processing circuits while being buffered with the DRAM 16 by the ENDEC 14. Further, the data is read (read) by a host computer (for example, a personal computer) via an ATAPI interface unit 18 which is an interface unit with the host computer. The CPU 10 in FIG. 8 controls the ENDEC 14.
[0004]
When transferring data from the ATAPI interface unit 18 to the host computer 20, the ATAPI transfer method includes PIO, single word DMA, multi-word DMA, Ultra DMA transfer, and the like. Among these, Ultra DMA transfer is a transfer method having a high transfer rate.
[0005]
Five modes from MODE0 to MODE4 are defined for the Ultra DMA transfer. The maximum transfer rate in each mode is as follows.
・ MODE0: 16.6 Mbyte / sec
・ MODE1: 22Mbyte / sec
・ MODE2: 33Mbyte / sec
・ MODE3: 44Mbyte / sec
・ MODE4: 66Mbyte / sec
[0006]
The optical disk device 2 and the host computer 20 that use Ultra DMA transfer generate (calculate) a CRC (Cyclic Redundancy check) code of the transferred data in both the host computer 20 and the optical disk device 2. , A CRC check function of comparing the results is usually provided. This CRC check function is for improving the reliability of data transfer.
[0007]
In the related art, when a CRC error is detected during data transfer from the optical disk device to the host computer, the transfer speed is reduced and the transfer is performed again. Although this technique increases reliability, it does not perform as well because it reduces transfer speed.
[0008]
For example, in the invention according to Patent Document 1 described below, in the case of retrying a command that has resulted in a CRC error, the current control circuit in the disk controller is controlled to reduce the value of the current for driving the interface signal line of the host interface, and The transfer rate control circuit in the disk controller is controlled to lower the data transfer rate and start data transfer with the host computer.
[0009]
[Patent Document 1]
JP-A-11-249821
[Problems to be solved by the invention]
According to the present invention, when data is transferred from the optical disk device to the host computer, the reliability of the data transfer is not increased only by the CRC check function, but the reliability is further improved by controlling the strobe signal from the optical disk device. The purpose is to measure. It is another object of the present invention that the transfer can be performed without lowering the transfer speed.
[0011]
[Means for Solving the Problems]
The present invention has been made to achieve the above object. An optical disc device according to claim 1 of the present invention is a
This is an optical disk device connected to a host computer having a CRC code generation unit. The optical disk device is
Means for transferring experimental data to a host computer;
Means for generating a strobe signal with a staggered rise or fall at minute intervals with respect to the experimental data,
Means for detecting whether the data transfer to the host computer is normal or abnormal by comparing the CRC code from the CRC code generation means of the host computer with the CRC code generated in the optical disk device;
A strobe signal control means for selecting an appropriate strobe signal based on a plurality of signals generated by the means for detecting whether data transfer to the host computer is normal or abnormal.
[0012]
An optical disk interface system according to claim 2 according to the present invention,
Including an optical disk device and a host computer connected to the optical disk device,
The host computer has a CRC code generating means,
The above optical disk device,
Means for transferring experimental data to a host computer;
Means for generating a strobe signal with a staggered rise or fall at minute intervals with respect to the experimental data,
Means for detecting whether the data transfer to the host computer is normal or abnormal by comparing the CRC code from the CRC code generation means of the host computer with the CRC code generated in the optical disk device;
A strobe signal control means for selecting an appropriate strobe signal based on the plurality of signals generated by the means for detecting whether the data transfer to the host computer is normal or abnormal.
[0013]
The optical disk device according to claim 3 according to the present invention,
An optical disk device connected to a host computer having means for continuously generating a strobe signal at a small interval with a rising or falling edge shifted for transferred data and a CRC code generating means. The optical disk device is
Means for detecting whether the data transfer to the host computer is normal or abnormal by comparing the CRC code from the CRC code generation means of the host computer with the CRC code generated in the optical disk device;
A strobe signal control means for selecting an appropriate strobe signal based on a plurality of signals generated by the means for detecting whether data transfer to the host computer is normal or abnormal.
[0014]
An optical disk interface system according to claim 4 according to the present invention,
Including an optical disk device and a host computer connected to the optical disk device,
The host computer has means for continuously generating a strobe signal at a small interval with a rising or falling edge shifted for transferred data, and a CRC code generating means,
The above optical disk device,
Means for detecting whether the data transfer to the host computer is normal or abnormal by comparing the CRC code from the CRC code generation means of the host computer with the CRC code generated in the optical disk device;
A strobe signal control means for selecting an appropriate strobe signal based on the plurality of signals generated by the means for detecting whether the data transfer to the host computer is normal or abnormal.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments according to the present invention will be described with reference to the drawings.
[0016]
As shown in FIG. 1, when the host computer 20 and the optical disk device 2 are connected via the ATAPI interface unit 18 and are transferred by Ultra DMA transfer, the data (DD [16: 0]) and the strobe signal (DTROBE) are Output from the optical disk device 2 to the host computer 20.
[0017]
FIG. 2 shows an example of a timing chart of data output from the optical disk device 2 and a strobe signal. In the Ultra DMA transfer, the strobe signal takes data at both rising and falling. Incidentally, the setup time (“tDVS” in FIG. 2) and the hold time (“tDVH” in FIG. 2) with respect to the rising (or falling) of the strobe signal are restricted by the ATA / ATAPI standard (see Table 1 below). Table 1 conforms to ATA / ATAPI5.) If the standard is not satisfied, there is a possibility that desired data transfer cannot be performed.
[Table 1]

[0018]
Hereinafter, an embodiment will be described in which the position of the strobe is changed for the data output from the optical disk device 2, the corresponding CRC code is generated by the host computer, and the strobe signal is controlled based on the generated code. .
[0019]
<< 1st Embodiment >>
In the first embodiment shown in FIG. 3, the position of the strobe is changed on the optical disk device 2 side with respect to the data output from the optical disk device 2.
[0020]
In the first embodiment, data transfer as shown in FIG. 4 is performed on a trial basis before normal data is transferred. DD [15: 0] is synchronized with the internal clock (clk). Therefore, how many clocks are included in the section (1) in FIG. 4 is determined. In the case of FIG. 4, it is for five clocks. Therefore, the number of strobe signals that can be synchronized with the internal clock in the section (1) can be determined by the strobe counter 30. In the case of FIG. 4, there are 10 types of A to J.
[0021]
First, the strobe is transferred to the host computer 20 as an earlier timing of "A" in FIG. Then, a CRC code is generated by the CRC generation circuit 38 of the host computer 20, and the CRC code is returned to the optical disk device 2. The CRC code sent from the host computer 20 is compared with a CRC code generated in advance in the optical disk device 2 by the CRC comparison circuit 32. If they match, the bit of CRCOK [0] is set to "1". If they do not match, the bit of CRCNG [0] is set to “1”. In the case of FIG. 4, since there are ten types of strobes, CRCOK and CRCNG have a bus width of 10 bits.
[0022]
Next, the strobe counter 30 counts 1 and transfers the strobe to the host computer 20 at the timing "B" in FIG. Then, in the same manner as described above, the CRC comparison circuit 32 of the optical disk device 2 determines OK / NG, and the result is represented by CRCOK [1] / CRCNG [1] bits.
[0023]
Thereafter, similarly, the strobe is transferred to the host computer 20 until the timings "C", "D", "E", "F", "G", "H", "I" and "J" in FIG. The generated CRC code is compared. The results are represented by CRCOK [2] to [9] / CRCNG [2] to [9].
[0024]
For example, CRCOK [9: 0]
0 0 0 0 1 1 1 1 1 1 0
If so, the strobe control circuit 28 determines that the strobe signal of “G”, which is the intermediate point between the points that are continuously “1”, is optimal. Then, the strobe control of selecting the “G” strobe is performed.
[0025]
As described above, the strobe control circuit 28 on the device side detects the intermediate point of the points that are continuously “1” in the 10 bits of CRCOK [9: 0], so that the optimum strobe is determined. Can be found.
[0026]
Incidentally, in the first embodiment shown in FIG. 3, an NG bit output from the CRC comparison circuit 32 is provided to distinguish between normal data transfer and test data transfer. This NG bit is set to “1” when a CRC error occurs in normal data transfer, and controls the selectors 34 and 36 at the end. During normal data transfer, "0" is selected for these selectors 34 and 36. Therefore, at this time, the CRC from the data from the DRAM 16 is generated by the optical disk device 2 and the host computer 20, respectively, and is compared by the CRC comparison circuit 32.
[0027]
When a CRC error (that is, the NG bit is “1”) occurs in normal data transfer, the flow is as shown in the flowchart of FIG. When the NG bit becomes "1" in the data transfer (step S02) (step S04), "1" is selected for the selectors 34 and 36 in FIG. At this time, test data is output from the data generation circuit 22 to the host computer 20 as DD [15: 0] (step S06).
[0028]
At the start of the test data, the strobe counter 30 counts the position of the strobe as shown in FIG. In response to the count, the strobe control circuit 28 outputs a strobe to the host computer 20 at the timing "A" in FIG. 4 (step S06). Then, the CRC at the strobe at the timing "A" in FIG. 4 is generated between the optical disk device 2 and the host computer 20 (step S10), and the CRC comparison circuit 32 performs a CRC comparison (step S12). After that, CRCOK / CRCNG is output to the strobe control circuit 28.
[0029]
Thereafter, the CRC is also compared by the same operation for the strobes related to B to J in FIG. 4 (step S08). In response to these comparison results, the strobe control circuit 28 determines the optimum strobe position and transmits it to the strobe generation circuit 26. When the signal output from the strobe counter 30 to the CRC comparator 32 has counted up to J in FIG. 4, the NG bit is cleared (to "0") (step S16). As described above, the strobe generating circuit 26 transmits an optimum strobe, and thus data transfer is performed in an optimum state.
[0030]
In the example shown in FIG. 4, the strobe signal is synchronized with the internal clock. However, the strobe signal may be assigned more finely. In this case, strobes are established at various intervals in the section (1) asynchronously with the internal clock. Also in this case, as many registers as CRCOK / CRCNG must be secured as many as the number of strobes (the number of times a CRC code is generated).
[0031]
<< 2nd Embodiment >>
In the second embodiment shown in FIG. 6, the position of the strobe is changed on the host computer 20 side with respect to the data output from the optical disk device 2.
[0032]
In the mechanism according to the second embodiment, the data transfer as in the first embodiment is not performed on a trial basis, and the mechanism operates in normal data transfer. First, DD [15: 0] is synchronized with the internal clock (clk). Therefore, how many clocks are included in the section (1) in FIG. 4 is determined. In the case of FIG. 4, it is for 5 clocks.
[0033]
The host computer 20 generates a clock similar to the internal clock of the optical disk device 2. The number of strobe signals that can be generated in the section shown in FIG. 4A can be determined by the strobe counter 40. There are 10 types of A to J.
[0034]
In the second embodiment, a strobe is generated by the strobe counter 40 of the host computer 20. Since this strobe generation is performed for normal data transfer, it is not necessary to repeatedly perform data transfer from the optical disk device 2 as in the first embodiment.
[0035]
First, when the strobe is at the point A, a CRC code is generated and returned to the optical disk device 2. In the optical disc device 2, the CRC code returned from the host computer 20 is compared with a CRC code generated in the optical disc device 2 in advance by the CRC comparison circuit 32. The bit is set to “1”, and if they do not match, the bit of CRCNG [0] is set to “1”. Since there are ten types of strobes, CRCOK and CRCNG have a bus width of 10 bits.
[0036]
After generating a CRC code when the strobe is at point A, the CRC generation circuit 38 of the host computer 2 continuously generates a CRC for the strobes from point B to point J, and continuously generates the CRC to the optical disk device 2. return. Then, in the same manner as described above, the CRC comparison circuit 32 of the optical disk device 2 continuously determines OK / NG, and the result is represented by CRCOK [1] to [9] / CRCNG [1] to [9]. .
[0037]
For example, CRCOK [9: 0]
0 0 0 0 1 1 1 1 1 1 0
If so, the strobe control circuit 28 determines that the strobe signal of “G”, which is the intermediate point between the points that are continuously “1”, is optimal. Then, the strobe control of selecting the “G” strobe is performed.
[0038]
In this case, since the point G is three clocks after the point A, the point three clocks after the strobe signal output from the optical disk device 2 is the optimum strobe position.
[0039]
Incidentally, also in the second embodiment of FIG. 6, the CRC comparison circuit 32 outputs NG bits. FIG. 7 is a flowchart from data transfer to NG bit confirmation / use. When reading (reading) data from the DRAM 16, CRCs are generated on the optical disk device 2 side and the host computer 20 side, respectively, and are compared by the CRC comparison circuit 32. When data transfer is successful (that is, when there is no difference in the CRC comparison circuit 32), the NG bit remains “0”. When the NG bit is “0”, the strobe generation circuit 26 of the optical disk device 2 does not refer to the strobe position from the strobe control circuit 28. Therefore, the host computer 20 continues reading (reading) as it is.
[0040]
When an error occurs in the data transfer (that is, when a difference occurs in the CRC comparison circuit 32), the NG bit becomes “1”, and the position of the strobe determined in advance during the data transfer is determined by the strobe control circuit 28. The signal is transmitted to the strobe generation circuit 26 and controls the strobe (FIG. 7, step S62).
[0041]
In order to determine the optimum strobe position in advance, the strobe counter 40 determines continuous strobe positions for the data to be transferred (step 52) (for example, A to J in FIG. 4), and a strobe generation circuit on the host computer 20 side. At 42, a strobe is generated for each strobe position (step S54), a CRC is issued for each strobe, and the optical disk device 2 compares them (step S56) to determine an optimal strobe position (step S58). ).
[0042]
When the NG bit becomes "1", the optimum strobe is transmitted from the strobe control circuit 28 to the strobe generation circuit 26, and then the NG bit is cleared (step S62).
[0043]
Also in the description of the second embodiment, the strobe signal is synchronized with the internal clock, but the strobe may be assigned more finely. In this case, strobes are established at various intervals in the section (1) asynchronously with the clock of the host computer 20. Also in this case, as many registers as CRCOK / CRCNG must be secured as many as the number of strobes (the number of times a CRC code is generated).
[0044]
In the first embodiment, since the optical disk device 2 changes the strobe, the strobe must be transferred to the host computer 20 each time. On the other hand, in the second embodiment, the strobe is changed by the host computer 20. Because of the change, the control time is shorter than in the first embodiment, and strobe control can be performed even during data transfer.
[0045]
【The invention's effect】
By utilizing the present invention, the following effects can be obtained.
[0046]
By optimizing the position of the strobe when data is transferred from the optical disk device to the host computer, transfer reliability is improved.
[0047]
Further, when data is transferred from the optical disk device to the host computer, the strobe timing can be changed on the host computer side. To optimize the position of the strobe, and therefore, it is possible to perform optimal strobe control in a short time.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing data and a strobe signal sent from an optical disk device to a host computer.
FIG. 2 is an example of a timing chart of data output from an optical disk device and a strobe signal.
FIG. 3 is a block diagram of a circuit in the optical disk device and a host computer according to the first embodiment of the present invention.
FIG. 4 is a pattern of generation of a strobe signal according to the present invention.
FIG. 5 is an example of a flowchart of an operation according to the first embodiment of the present invention.
FIG. 6 is a block diagram of a circuit in an optical disk device and a host computer according to a second embodiment of the present invention.
FIG. 7 is an example of a flowchart of an operation according to the second embodiment of the present invention.
FIG. 8 is a block diagram of a general optical disk device.
[Explanation of symbols]
2 ... optical disk device, 10 ... CPU, 16 ... DRAM, 18 ... ATAPI interface unit, 20 ... host computer.

Claims (4)

In an optical disk device connected to a host computer having a CRC code generating means,
Means for transferring experimental data to a host computer;
Means for generating a strobe signal with a staggered rise or fall at minute intervals with respect to the experimental data,
Means for detecting whether the data transfer to the host computer is normal or abnormal by comparing the CRC code from the CRC code generation means of the host computer with the CRC code generated in the optical disk device;
A strobe signal control unit for selecting an appropriate strobe signal based on a plurality of signals generated by the unit for detecting whether the data transfer to the host computer is normal or abnormal,
Optical disk device. Including an optical disk device and a host computer connected to the optical disk device,
The host computer has a CRC code generating means,
The above optical disk device,
Means for transferring experimental data to a host computer;
Means for generating a strobe signal with a staggered rise or fall at minute intervals with respect to the experimental data,
Means for detecting whether the data transfer to the host computer is normal or abnormal by comparing the CRC code from the CRC code generation means of the host computer with the CRC code generated in the optical disk device;
Strobe signal control means for selecting an appropriate strobe signal based on a plurality of signals generated by the means for detecting whether the data transfer to the host computer is normal or abnormal,
Optical disk interface system. In an optical disc device connected to a host computer having means for continuously generating strobe signals with shifted rising or falling at minute intervals with respect to transferred data and CRC code generating means,
Means for detecting whether the data transfer to the host computer is normal or abnormal by comparing the CRC code from the CRC code generation means of the host computer with the CRC code generated in the optical disk device;
A strobe signal control unit for selecting an appropriate strobe signal based on a plurality of signals generated by the unit for detecting whether the data transfer to the host computer is normal or abnormal,
Optical disk device. Including an optical disk device and a host computer connected to the optical disk device,
The host computer has means for continuously generating a strobe signal at a small interval with a rising or falling edge shifted for transferred data, and a CRC code generating means,
The above optical disk device,
Means for detecting whether the data transfer to the host computer is normal or abnormal by comparing the CRC code from the CRC code generation means of the host computer with the CRC code generated in the optical disk device;
Strobe signal control means for selecting an appropriate strobe signal based on a plurality of signals generated by the means for detecting whether the data transfer to the host computer is normal or abnormal,
Optical disk interface system.

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