Slew-rate control device, storage device, and slew-rate control method
View Patent ↗A slew-rate control device controls a slew rate of a control signal based on which data reading or data writing is performed with respect to a storage medium. A retry executing unit changes, when an error occurs during the data reading or the data writing, the slew rate of the control signal, and executes a retry of the data reading or the data writing. A slew-rate setting unit sets, as the slew rate of the control signal, a slew rate with which the retry is successfully executed.
1. A slew-rate control device that controls a slew rate of a control signal based on which data reading or data writing is performed with respect to a storage medium, the slew-rate control device comprising:
a memory unit that preliminarily retains a plurality of slew-rate setting values;
a processing unit that changes, when an error occurs during the data reading or the data writing, the slew rate of the control signal to one of the plurality of slew-rate setting values retained in the memory unit;
a retry executing unit that executes a retry of the data reading or the data writing with the one of the plurality of slew-rate setting values changed by the processing unit; and
a slew-rate setting unit that sets, as the slew rate of the control signal, a slew rate with which the retry is successfully executed.
2. The slew-rate control device according to claim 1 , wherein:
the processing unit counts a number of retries, and changes the slew-rate to one of the plurality of slew-rate setting values retained in the memory unit based on the counted number of retries.
3. The slew-rate control device according to claim 2 , wherein:
the processing unit changes the slew-rate sequentially to one of the plurality of slew-rate setting values retained in the memory unit when the counted number of retries exceeds a predetermined threshold, and
the slew-rate setting unit sets, as the slew rate of the control signal, a slew rate with which the number of retries is minimized.
4. The slew-rate control device according to claim 2 , wherein:
the processing unit changes the slew-rate sequentially to one of the plurality of slew-rate setting values retained in the memory unit when the counted number of retries exceeds a predetermined threshold, and
the slew-rate setting unit sets, as the slew rate of the control signal, a slew rate with which an error rate is minimized in the retry.
5. The slew-rate control device according to claim 3 , wherein:
the retry executing unit executes the retry when the control signal is not exchanged for a predetermined time.
6. The slew-rate control device according to claim 4 , wherein:
the retry executing unit executes the retry when the control signal is not exchanged for a predetermined time.
7. The slew-rate control device according to claim 3 , wherein:
the storage unit includes a dummy area in which predetermined data is written, and
the retry executing unit executes the retry by using the predetermined data.
8. The slew-rate control device according to claim 4 , wherein:
the storage unit includes a dummy area in which predetermined data is written, and
the retry executing unit executes the retry by using the predetermined data.
9. The slew-rate control device according to claim 7 , wherein:
the predetermined data is a data formed by combining a bit string of successive bits of “0” and a bit string of successive bits of “1”.
10. The slew-rate control device according to claim 8 , wherein:
the predetermined data is a data formed by combining a bit string of successive bits of “0” and a bit string of successive bits of “1”.
11. A storage device that controls a slew rate of a control signal based on which data reading or data writing is performed with respect to a storage medium, the storage device comprising:
a memory unit that preliminarily retains a plurality of slew-rate setting values;
a processing unit that changes, when an error occurs during the data reading or the data writing, the slew rate of the control signal to one of the plurality of slew-rate setting values retained in the memory unit;
a retry executing unit that executes a retry of the data reading or the data writing with the one of the plurality of slew-rate setting values changed by the processing unit; and
a slew-rate setting unit that sets, as the slew rate of the control signal, a slew rate with which the retry is successfully executed.
12. The storage device according to claim 11 , wherein:
the processing unit counts a number of retries, and changes the slew-rate to one of the plurality of slew-rate setting values retained in the memory unit based on the counted number of retries.
13. The storage device according to claim 12 , wherein:
the processing unit changes the slew-rate sequentially to one of the plurality of slew-rate setting values retained in the memory unit when the counted number of retries exceeds a predetermined threshold, and
the slew-rate setting unit sets, as the slew rate of the control signal, a slew rate with which the number of retries is minimized.
14. The storage device according to claim 12 , wherein:
the processing unit changes the slew-rate sequentially to one of the plurality of slew-rate setting values retained in the memory unit when the counted number of retries exceeds a predetermined threshold, and
the slew-rate setting unit sets, as the slew rate of the control signal, a slew rate with which an error rate is minimized in the retry.
15. A method of controlling a slew rate of a control signal based on which data reading or data writing is performed with respect to a storage medium, the method comprising:
preliminarily retaining a plurality of slew-rate setting values;
changing, when an error occurs during the data reading or the data writing, the slew rate of the control signal to one of the plurality of slew-rate setting values retained by the retaining step;
executing a retry of the data reading or the data writing with the one of the plurality of slew-rate setting values changed by the changing step; and
setting, as the slew rate of the control signal, a slew rate with which the retry is successfully executed.
16. The method according to claim 15 , wherein
the changing step further includes:
counting number of retries; and
changing the slew-rate to one of the plurality of slew-rate setting values based on the counted number of retries.
17. The method according to claim 16 , wherein:
the changing step includes changing the slew-rate sequentially to one of the plurality of slew-rate setting values when the counted number of retries exceeds a predetermined threshold, and
the setting step includes setting, as the slew rate of the control signal, a slew rate with which the number of retries is minimized.
18. The method according to claim 16 , wherein:
the changing step includes changing the slew-rate sequentially to one of the plurality of slew-rate setting values when the counted number of retries exceeds a predetermined threshold, and
the setting step includes setting, as the slew rate of the control signal, a slew rate with which an error rate is minimized in the retry.