U.S. patent application number 09/072276 was filed with the patent office on 2001-08-09 for high-speed unified data interface for a read channel in a disk drive system.
Invention is credited to HILL, JOHN P..
Application Number | 20010012166 09/072276 |
Document ID | / |
Family ID | 26747061 |
Filed Date | 2001-08-09 |
United States Patent
Application |
20010012166 |
Kind Code |
A1 |
HILL, JOHN P. |
August 9, 2001 |
HIGH-SPEED UNIFIED DATA INTERFACE FOR A READ CHANNEL IN A DISK
DRIVE SYSTEM
Abstract
The invention provides a high-speed interface that transfers
user data and other data over a single unified interface between a
read channel integrated circuit and another integrated circuit,
such as the drive control integrated circuit. The high-speed
interface eliminates the need for analog pins on the integrated
circuits to lower the cost of the system. The high-speed interface
also eliminates the use of the serial interface to transfer the
servo position data and other data which speeds up the data
transfer. Examples of the other data include read channel settings,
read channel performance data, and servo data. A read channel
integrated circuit exchanges the user data with a data bus when the
disk drive system is reading or writing the user data. The read
channel integrated circuit exchanges the other data with the data
bus when the disk drive system is reading servo data. The other
integrated circuit exchanges the user data with the data bus when
the disk drive system is reading or writing the user data. The
other integrated circuit exchanges the other data with the data bus
when the disk drive system is reading the servo data. The data bus
transfers the user data and the other data between the integrated
circuits.
Inventors: |
HILL, JOHN P.; (NEDERLAND,
CO) |
Correspondence
Address: |
LISA JORGENSON, ESQ.
ST MICROELECTRONICS, INC.
1310 ELECTRONICS DRIVE
CARROLLTON
TX
75006-5039
US
|
Family ID: |
26747061 |
Appl. No.: |
09/072276 |
Filed: |
May 4, 1998 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60066701 |
Nov 25, 1997 |
|
|
|
Current U.S.
Class: |
360/46 ;
360/75 |
Current CPC
Class: |
G06F 3/0676 20130101;
G06F 3/061 20130101; G06F 3/0655 20130101 |
Class at
Publication: |
360/46 ;
360/75 |
International
Class: |
G11B 005/09; G11B
021/02 |
Claims
What is claimed is:
1. A system for transferring user data and other data in a disk
drive system, the system comprising: a data bus operational to
transfer the user data and the other data; a read channel
integrated circuit operationally coupled to the data bus and
operational to exchange the user data with a data bus when the disk
drive system is reading or writing the user data and to exchange
the other data with the data bus when the disk drive system is
reading servo data; and another integrated circuit operationally
coupled to the data bus and operational to exchange the user data
with the data bus when the disk drive system is reading or writing
the user data and operational to exchange the other data with the
data bus when the disk drive system is reading the servo data.
2. The system of claim 1 wherein the other integrated circuit is a
drive manager integrated circuit.
3. The system of claim 1 wherein the data bus is a Non-Return to
Zero bus.
4. The system of claim 1 wherein the other data includes read
channel integrated circuit settings.
5. The system of claim 1 wherein the other data includes read
channel integrated circuit performance data.
6. The system of claim 1 wherein the other data includes servo
data.
7. The system of claim 1 that further comprises: a disk operational
to store the user data and the servo data; a head operational to
read the user data and the servo data from the disk and transfer
the user data and the servo data to a pre-amp; and a pre-amp
operationally coupled to the head and operational to transfer the
user data and the servo data to the read channel integrated
circuit.
8. The system of claim 1 wherein the read channel integrated
circuit further comprises a multiplexer operational to multiplex
the user data and the other data.
9. The system of claim 1 wherein the other integrated circuit
further comprises a multiplexer operational to de-multiplex the
user data and the other data.
10. The system of claim 1 wherein the other integrated circuit
further comprises a processor operational to use the other data to
control positioning of a head relative to a disk device.
11. The system of claim 1 wherein the other integrated circuit
further comprises a disk controller operational to transfer the
user data to a user.
12. A read channel integrated circuit that comprises: an
encoder/decoder operational to receive and process user data; a
memory operational to store other data; and a multiplexer
operationally coupled to the memory and to the encoder/decoder, and
wherein the multiplexer is operational to multiplex the user data
and the other data and transfer the multiplexed data to a data
bus.
13. A drive control integrated circuit that comprises: a
multiplexer operational to receive multiplexed data from a data bus
and de-multiplex the multiplexed data into user data and other
data; a processor operationally coupled to the multiplexer and
operational to use the other data; and a disk controller
operationally coupled to the multiplexer and operational to
transfer the user data to a user.
14. A method for transferring user data and other data in a disk
drive system, the system comprising: exchanging the user data over
a data bus between a read channel integrated circuit and another
integrated circuit when the disk drive system is reading or writing
the user data; and exchanging the other data over the data bus
between the read channel integrated circuit and the other
integrated circuit when the disk drive system is reading servo
data.
15. The method of claim 14 wherein the other integrated circuit is
a drive manager integrated circuit.
16. The method of claim 14 wherein the data bus is a Non-Return to
Zero bus.
17. The method of claim 14 wherein the other data includes read
channel integrated circuit settings.
18. The method of claim 14 wherein the other data includes read
channel integrated circuit performance data.
19. The method of claim 14 wherein the other data includes servo
data.
20. The method of claim 14 further comprising reading the user data
and servo position data from a disk device and transferring the
user data and the servo position data to the read channel
integrated circuit.
21. The method of claim 14 further comprising multiplexing the user
data and the other data in the read channel integrated circuit.
22. The method of claim 14 further comprising de-multiplexing the
user data and the other data in the other integrated circuit.
23. The method of claim 14 further comprising using the other data
in the other integrated circuit to control positioning of a head
relative to a disk device.
24. The method of claim 14 further comprising transferring the user
data from the other integrated circuit to a user.
Description
RELATED APPLICATION
[0001] This patent application references U.S. provisional patent
application No. 60/066701 filed on Nov. 25, 1997.
FIELD OF THE INVENTION
[0002] The invention is related to the field of disk drive systems,
and in particular, to a high-speed interface that transfers user
data and other data between a read channel integrated circuit and
another integrated circuit.
PROBLEM
[0003] A magnetic disk system stores user data in data tracks on
the surface of a disk device. The user data is transferred between
the disk and the user as follows. A head is positioned over a
circular data track and reads the user data as the disk spins. The
head transfers the user data to a pre-amp, and the pre-amp
transfers the user data to a read channel integrated circuit. The
read channel integrated circuit processes and transfers the user
data to a drive manager integrated circuit over a high-speed bus,
such as a Non-Return to Zero (NRZ) bus. The drive manager
integrated circuit transfers the user data to the user.
[0004] The magnetic disk system also stores servo position data in
servo sectors on the surface of the disk device. The servo sectors
are interspersed along the circular data tracks so that the head
periodically encounters the servo sectors as the disk spins. When
the heads are positioned over a servo sector, they transfer servo
data and not user data. When the heads are positioned over a data
sector with user data, they transfer user data and not servo
data.
[0005] A servo system uses the servo position data to position a
read/write head over a data track that contains the desired user
data. One form of servo position data is coarse-resolution data
that identifies the data track that is under the head.
Coarse-resolution data has a resolution of plus or minus one track
and does not have the resolution to center the head over the data
track. The other form of servo position data is high-resolution
data that indicates how far off-center a head is relative to the
data track. The servo system uses the coarse-resolution data to
position a head near the proper data track and uses the
high-resolution data to center the head over the center of that
track. The servo system must have the servo position data to
effectively store or retrieve user data.
[0006] Servo position data is transferred from the disk to the
servo system as follows. A read/write head reads the servo position
data from the disk device. The read/write head transfers the servo
position data through a pre-amp to a read channel integrated
circuit. The read channel integrated circuit processes the servo
position data and transfers the processed data to a drive manager
integrated circuit. A processor in the drive manager integrated
circuit uses the servo position data to direct the servo system to
position the head.
[0007] One prior system for transferring servo position data from
the disk to the processor uses dedicated analog connections to
transfer the high-resolution data from the read channel integrated
circuit to the drive control integrated circuit. The analog lines
require dedicated pins on each integrated circuit that increase the
cost of the integrated circuits, and the corresponding cost of the
disk drive systems that incorporate the integrated circuits. The
course-resolution data is transferred from the read channel
integrated circuit to the drive control integrated circuit by lines
that transmit a representation of the data pulses in the
coarse-resolution servo data field. These lines are sometimes
referred to as pulse/polarity lines.
[0008] Another prior system for transferring servo position data
from the disk to the processor uses the read channel integrated
circuit to convert the high-resolution data from analog to digital.
This prior system then transfers the high-resolution data over a
serial interface between the read channel integrated circuit and
the drive control integrated circuit. Although, the
course-resolution data is still transferred by the pulse/polarity
lines, it could be decoded in the read channel integrated circuit
and transferred to the drive control integrated circuit over the
serial interface. The serial interface can be slow given the
typical baud rate and the increase in the amount of servo position
data. Unfortunately, the slow speed of the serial interface may
limit the accurate positioning of the head to read or write data.
The slow speed of the serial interface also limits the ability of
the servo system to follow high-density data tracks that increase
drive capacity. In addition, it is undesirable to transfer data
over the serial interface while data is being read due to signal to
noise issues.
[0009] Prior systems also use the serial interface to transfer
control information between the drive manager integrated circuit
and the read channel integrated circuit. The processor in the drive
manager integrated circuit transfers control information to
configuration registers in the read channel integrated circuit. The
control information contains settings that control the operation of
the read channel integrated circuit. The control information can
also request information such as the course-resolution data,
high-resolution data, performance information, status and mode
information. If the control information could be transferred
through another means, the serial bus could be eliminated to
eliminate pins and save cost.
[0010] At present, there is a need for a more efficient system to
transfer servo position data from the read channel integrated
circuit to the drive manager integrated circuit. Such a system
should transfer the servo position data at high speeds and should
eliminate the analog pins on the integrated circuits. There is also
a need for an alternative means to transfer control information
from the drive manager integrated circuit to the read channel
integrated circuit.
SOLUTION
[0011] The invention overcomes the above problems by providing a
high-speed interface that exchanges user data and other data
between the read channel integrated circuit and another integrated
circuit, such as the drive manager integrated circuit. The
high-speed interface eliminates the need for analog pins on the
integrated circuits to transfer high-resolution servo position
data, and thus lowers the cost of the system. The high-speed
interface eliminates the need to use the serial interface to
transfer servo position data, and thus speeds up the data transfer.
The high-speed interface eliminates the need to use the serial
interface to transfer read channel control information, and thus
the serial interface could be eliminated to save cost.
[0012] The invention includes methods, systems, and integrated
circuits for transferring user data and other data in a disk drive
system. A read channel integrated circuit exchanges the user data
with a data bus when the disk drive system is reading or writing
the user data. The read channel integrated circuit exchanges the
other data with the data bus when the disk drive system is reading
servo data. The other integrated circuit exchanges the user data
with the data bus when the disk drive system is reading or writing
the user data. The other integrated circuit exchanges the other
data with the data bus when the disk drive system is reading the
servo data. The data bus transfers the user data and the other data
between the integrated circuits. One example of the other
integrated circuit is a drive manager integrated circuit. One
example of the data bus is a Non-Return to Zero (NRZ) bus. Examples
of the other data include read channel integrated circuit settings,
read channel integrated circuit performance data, servo data,
high-resolution servo data, and coarse-resolution servo data.
[0013] The read channel integrated circuit is able to exchange the
other data with the data bus when the head is positioned over a
servo sector because no user data is being transferred over the
data bus during this period. Using the same high-speed data bus
that transfers user data to also transfer other data represents a
distinct advance in the art. Use of the high-speed bus to transfer
the other data at high speed increases system performance and data
transfer capacity while minimizing pin count.
DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a block diagram of a version of the invention and
depicts a disk drive system.
[0015] FIG. 2 is a block diagram of a servo sector.
[0016] FIG. 3 is a block diagram of a known read channel integrated
circuit and drive control integrated circuit.
[0017] FIG. 4 is a block diagram of a known read channel integrated
circuit and drive control integrated circuit.
[0018] FIG. 5 is a block diagram of a version of the invention and
depicts a read channel integrated circuit and a drive control
integrated circuit.
DETAILED DESCRIPTION
[0019] System Configuration and Operation--FIG. 1
[0020] FIG. 1 depicts a user 100 that is coupled to a disk drive
system 101. The user 100 stores and retrieves user data from the
disk drive system 101. One example of the user 100 is a personal
computer. The disk drive system 101 includes a disk device 102 that
is coupled to a read channel integrated circuit 103. The read
channel integrated circuit 103 is coupled to a drive control
integrated circuit 104, and the drive control integrated circuit
104 is coupled to the user 100. Those skilled in the art appreciate
that some conventional elements of the disk drive system 101 have
been omitted for reasons of clarity.
[0021] The disk device 102 is comprised of disks 105, heads 106,
and a pre-amp 107. The heads 106 read and write data to the disks
105. The pre-amp 107 connects one of the heads to the read channel
integrated circuit 103. The disk device 102 is conventional and can
be the VOYAGER 3 supplied by Samsung.
[0022] The read channel integrated circuit 103 provides the system
interface to the heads 106 of the disk device 102. When data is
written, the read channel integrated circuit 103 encodes the data
and transfers the data to one of the heads 106 through the pre-amp
107. When data is read, the read channel integrated circuit 103
receives a read signal from one of the heads 106 through the
pre-amp 107. The read channel integrated circuit 103 separates the
user data and the servo position data in the read signal for
individual processing.
[0023] The read channel integrated circuit 103 uses a multiplexer
to exchange user data and other data with the disk control
integrated circuit 104 over a data bus, such as a high-speed
Non-Return to Zero (NRZ) bus. The read channel integrated circuit
103 exchanges the user data with the data bus when the disk device
102 is reading the user data and is not reading the servo data. The
read channel integrated circuit 103 exchanges the other data with
the data bus when the disk device 102 is reading the servo data and
is not reading the user data. Some examples of the other data
include servo data, read channel settings, and read channel
performance data. The read channel integrated circuit 103 could be
adapted from the model # ADRT 1000 supplied by Analog Devices.
[0024] The drive control integrated circuit 104 controls the
operation of the disk drive system 101. The drive control
integrated circuit 104 controls the position of the heads 106
relative to the disks 105. The drive control integrated circuit 104
controls the data transfer between the user 100 and the disk drive
system 101. The drive control integrated circuit 104 is used in
some embodiments of the invention, but those skilled in the art are
aware that the functionality of the drive control integrated
circuit 104 can be distributed among multiple inter-connected
integrated circuits. The invention is not restricted to the use of
a single drive control integrated circuit 104, but also encompasses
the use of a configuration of integrated circuits that interface
with the read channel integrated circuit to 103 to transfer user
data and other data over a data bus.
[0025] The drive control integrated circuit 104 exchanges the user
data with the data bus when the disk device 102 is reading the user
data and is not reading the servo data. The drive control
integrated circuit 104 exchanges the other data with the data bus
when the disk device 102 is reading the servo data and is not
reading the user data. The drive control integrated circuit 104
exchanges the user data with the user 100 and the other data with
the appropriate processing functions in the drive control
integrated circuit 104. The drive control integrated circuit 104
can be adapted from the AIC-5460 supplied by Adaptec of Milipitas,
Calif.
[0026] In operation, the user 100 stores and retrieves user data as
follows. The user 100 transfers the user data to the drive control
integrated circuit 104. The drive control integrated circuit 104
multiplexes the user data and the other data onto a data bus for
transfer to the read channel integrated circuit 103. The drive
control integrated circuit 104 uses servo position data to direct
the positioning of the heads 106 to the proper location on the
disks 105 for user data storage. The read channel integrated
circuit 103 de-multiplexes the user data and the other data from
the data bus. The read channel integrated circuit 103 encodes the
user data and transfers the user data to the pre-amp 107. The
pre-amp 107 transfers the user data to one of the heads 106 that is
selected by the drive control integrated circuit 104. The selected
head writes the user data to the data track on the disks 105 that
is positioned under the head.
[0027] To retrieve the user data, the selected head 106 is
re-positioned over the data track on the disks 105 under the
control of the drive control integrated circuit 104. The head reads
the user data and the servo data that is under the head and
transfers the data to the pre-amp 107. The pre-amp 107 transfers
the data from the selected head to the read channel integrated
circuit 103. The read channel integrated circuit 103 separates the
user data and the servo position data. The read channel integrated
circuit 103 multiplexes the user data and the other data onto the
data bus for transfer to the drive control integrated circuit 104.
The drive control integrated circuit 104 de-multiplexes the user
data and the other data from the data bus. The drive control
integrated circuit 104 exchanges the user data with the user 100
and the other position data with the appropriate processing
functions in the drive control integrated circuit 104.
[0028] Underlying Technology--FIGS. 2-4
[0029] FIG. 2 depicts servo data 212 that is interspersed in a data
track 210 that contains user data 211. The user data 211 is the
information that a user of a disk drive system typically stores on
the disk drive system. Examples of the user data 211 include
application software, document files, and records. A number of
servo sectors that contain such servo data are periodically
interspersed along the data tracks of a disk drive system. The
servo data 212 contains automatic gain control information,
phase-locked loop timing information, and a servo timing mark. The
servo data 212 also contains servo position data 213 that is
comprised of coarse-resolution data 214 and high-resolution data
215. The coarse-resolution data 214 are pulses that are typically
encoded using the Grey Code and identify the data track 210. The
coarse-resolution data 214 has a resolution of one track and does
not have the resolution to center the head over the data track 210.
The high-resolution data 215 is comprised of servo bursts that
indicate how far off-center a head is relative to the data track
210. The servo system uses the coarse-resolution data 214 to
position a head near the data track 210 and uses the
high-resolution data 215 to center the head over the center of the
data track 210.
[0030] FIG. 3 depicts a disk drive system 301 that is known in the
art. The disk device 102 contains the user data 211 and the servo
data 212. The read channel integrated circuit 303 comprises signal
processor 320, configuration registers 321, servo pulse detector
322, servo burst detector 323, and encoder/decoder (endec) 324. The
drive control integrated circuit 304 comprises serial port 325,
servo decoder and memory 326, analog-to-digital (A/D) converter and
memory 327, disk controller 328, sequencer 329, processor 330, and
user interface 331. The read channel integrated circuit 303 and the
drive control integrated circuit 304 are connected by a serial
interface 332, analog lines 333, clock signal 334, NRZ bus 335, and
pulse/polarity lines 336.
[0031] In operation, the signal processor 320 receives a read
signal that contains the user data 211 and the servo data 212 from
the disk device 102. The signal processor 320 transfers the user
data 211 to the endec 324. The endec 324 transfers the user data
211 to the disk controller 328 over the NRZ bus 335. The disk
controller 328 forwards the user data 211 to the user 100 though
the user interface 331. The user data 211 is transferred from the
user 100 to the disk device 102 in a reciprocal manner.
[0032] The signal processor 320 transfers the servo data 212 to the
servo pulse detector 322, and the servo pulse detector 322 detects
the pulses comprising the coarse-resolution servo position data in
the servo data 212. The servo pulse detector 322 transfers the
coarse-resolution servo position data over the pulse/polarity lines
336 to the servo decoder and memory 326. The servo decoder and
memory 326 decodes the coarse-resolution servo position data and
stores it in memory. The processor 330 obtains the decoded
coarse-resolution servo position data from the servo decoder and
memory 326 and uses the coarse-resolution servo position data to
position the heads near the desired data tracks.
[0033] The signal processor 320 transfers the high-resolution servo
position data to the servo burst detector 323. The servo burst
detector 323 detects the amplitudes of the servo bursts in the
high-resolution servo position data using analog peak detection,
analog area detection, or variations of these well-known methods.
The servo burst detector 323 transfers the amplitude information
over the analog lines 333 to the A/D converter and memory 327. The
A/D converter and memory 327 converts the high-resolution servo
position data from analog-to-digital and stores the digital data in
memory. The processor 330 obtains the high-resolution servo
position data from the A/D converter and memory 327 and uses the
high-resolution servo position data to center the heads over the
desired data tracks.
[0034] The processor 330 provides configuration information to the
read channel integrated circuit 303. The configuration information
contains settings and variables that control the operation of read
channel integrated circuit 303. The processor 330 transfers the
configuration information to the serial port 325 for transfer over
the serial interface 332 to the configuration registers 321. The
signal processor 320 reads the configuration information from the
configuration registers 321 and operates accordingly.
[0035] The sequencer 329 receives timing information from the servo
decoder and memory 326 over the line 337. The timing information is
derived from the phase-locked-loop field and servo timing mark in
the servo data. The sequencer 329 uses the timing information to
provide a signal to the signal processor 320. The signal indicates
when the disk device 102 is reading or writing the user data 211
and when the disk device 102 is reading the servo data 212. The
heads do not transfer the user data 211 when they are positioned
over the servo data 212. Likewise, the heads do not transfer the
servo data 212 when they are positioned over the user data 211. As
a result, the NRZ bus 335 does not transfer the user data 211 when
the disk device 102 is reading the servo data 212.
[0036] FIG. 4 depicts another disk drive system 401 that is known
in the art. The disk drive system 401 is a modified version of the
disk drive system 301 of FIG. 3. The analog lines 333 and the A/D
converter and memory 327 of FIG. 3 have been removed. The servo
burst detector 323 and the A/D converter and memory 327 from FIG. 3
are combined into a servo burst detector and A/D converter element
440. The read channel integrated circuit 403 now converts the
high-resolution servo position data from analog-to-digital in the
element 440 and transfers the digital high-resolution servo
position data to the configuration registers 321. The processor 330
obtains the high-resolution servo position data over the serial
interface 332 and through the serial port 325. The configuration
registers 321 can also be read by the serial port 325. This allows
the processor 330 to obtain performance information or status from
the signal processor 320. The element 440 either detects analog
servo bursts and converts the results to digital information, or
the element 440 over-samples the servo bursts with an A/D converter
and uses a digital signal processor to detect the servo bursts from
the digital signal produced by the over-sampling.
[0037] Although not depicted on FIG. 4, the disk drive system 401
could be further modified by removing the servo decoder and memory
326 and integrating its functionality into the servo pulse detector
322. The servo pulse detector 322 would then transfer the
coarse-resolution data to the configuration registers 321. The
processor 330 would obtain both the coarse-resolution and
high-resolution servo position data over the serial interface 332
and through the serial port 325.
[0038] High-Speed Transfer of User Data and Other Data--FIG. 5
[0039] FIG. 5 depicts the user 500 coupled to a disk drive system
501 that is configured in accord with the present invention.
Components that are similar to those described above retain the
same last two digits of the reference number. The disk drive system
501 transfers the user data and other data over the high-speed NRZ
bus 535. Some examples of the other data include high-resolution
servo position data, coarse-resolution servo position data, read
channel performance information, read channel settings, timing
information, and other read channel information. The use of the
high-speed NRZ bus 535 eliminates the need for additional
interfaces and pins to transfer this other data and reduces cost.
The high-speed NRZ bus 535 transfers the servo position data and
read channel information faster than a serial interface to improve
system performance.
[0040] The disk device 502 stores user data 511 and servo data 512.
The read channel integrated circuit 503 comprises signal processor
520, configuration registers 521, servo pulse detector, decoder,
burst detector, and A/D converter element 545, separator and memory
550, mux/sequencer 551, and endec 524. The drive control integrated
circuit 504 comprises command port 525, combiner and memory 555,
mux/sequencer 553, disk controller 528, processor 530, and user
interface 531. The read channel integrated circuit 503 and the
drive control integrated circuit 504 are connected by a clock
signal 534, an NRZ bus 535, and timing information line 537.
[0041] In operation, the signal processor 520 receives a read
signal that contains the user data 511 and the servo data 512 from
the disk device 502. The signal processor 520 transfers the user
data 511 to the endec 524. The endec 524 transfers the user data
511 to the mux/sequencer 551. When the disk device 502 is reading
the user data 511, the mux/sequencer 551 transfers the user data
511 to the mux/sequencer 553 over the NRZ bus 535. The
mux/sequencer 553 transfers the user data 511 to the disk
controller 528. The disk controller 528 forwards the user data 511
to the user 500 though the user interface 531. The user data 511 is
transferred from the user 500 to the disk device 502 in a
reciprocal manner 511 where the mux/sequencer 553 transfers the
user data 511 to the mux/sequencer 551 over the NRZ bus 535 when
the disk device 502 is writing the user data 511.
[0042] The signal processor 520 transfers the servo data 512 in the
read signal to the servo pulse detector, decoder, burst detector,
and A/D converter element 545. The element 545 detects the pulses
in the coarse-resolution servo position data. The element 545 also
provides digital high-resolution servo position data. The element
545 either detects analog servo bursts and converts the results to
digital information, or the element 545 over-samples the servo
bursts with an A/D converter and uses a digital signal processor to
detect the servo bursts from the digital signal produced by the
over-sampling. The element transfers the coarse-resolution and
high-resolution servo position data to the separator and memory
550. The separator and memory 550 separates the servo position data
into data words that are the width of the NRZ bus and stores the
data words in a memory. The mux/sequencer 551 obtains the data
words containing the servo position data from the separator and
memory 550. This data will be sent when available in the separator
and memory 550 after being enabled by a command from command port
525 through mux/sequencer 553.
[0043] The signal processor 520 transfers read channel performance
data to the configuration registers 521. The mux/sequencer 551
obtains read channel performance data from the configuration
registers 521 after being enabled by a command from command port
525 through mux/sequencer 553. The mux/sequencer 551 transfers the
servo position data words and the read channel performance data to
the mux/sequencer 553 over the NRZ bus 535 when the disk device 502
is reading the servo data 512.
[0044] The mux/sequencer 553 transfers the read channel performance
data to the command port 525. The mux/sequencer 553 transfers the
servo position data words to the combiner and memory 555. The
combiner and memory 555 concatenates servo position data words that
are the width of the NRZ bus 535 into the coarse-resolution and
high-resolution servo position data and stores the data in a
memory. The memory could be a register array or a first-in
first-out memory. Those skilled in the art recognize that
separator/combiner elements may be required if the data sent
between the command port 525 and the configuration registers 521 is
a different width than the NRZ bus 535. This data includes
commands, status, and read channel performance data.
[0045] The processor 530 obtains the coarse-resolution and
high-resolution servo position data from the combiner and memory
555. The processor 530 uses the coarse-resolution servo position
data to position the heads near the desired data tracks, and uses
the high-resolution servo position data to center the heads over
the data tracks. The processor 530 obtains the read channel
performance data from the command port 525.
[0046] The processor 530 transfers read channel settings to the
command port 525, and the command port 525 transfers the read
channel settings to the mux/sequencer 553. The mux/sequencer 553
transfers the read channel settings to the mux/sequencer 551 over
the NRZ bus 535 when the disk device 502 is reading the servo data
512. The mux/sequencer 551 transfers the read channel settings to
the configuration registers 521. The signal processor 520 obtains
the read channel settings and operates accordingly.
[0047] The mux/sequencers 551 and 553 receive timing information
from the element 545 over the lines 537. Alternatively, the timing
information could be transferred over the NRZ bus 535. The timing
information is derived from the phase-locked-loop field and servo
timing mark in the servo data. The mux/sequencer 551 uses the
timing information to provide a sequence signal to the signal
processor 520, endec 524, separator and memory 550, and
configuration registers 521. The mux/sequencer 553 uses the timing
information to provide a sequence signal to the combiner and memory
555, the disk controller 528, and the command port 525. The
sequence signals indicate when the disk device 502 is reading or
writing the user data 511 and when the disk device 502 is reading
the servo data 512. The heads do not transfer the user data 511
when they are positioned over the servo data 512. Likewise, the
heads do not transfer the servo data 512 when they are positioned
over the user data 511. As a result, the NRZ bus 535 does not
transfer the user data 511 when the disk device 502 is reading the
servo data 512.
[0048] The transfer of commands, status, and performance data over
the NRZ bus 535 could occur during the first part of the servo data
data 512 and could consist of different data types during each
respective servo data field. The first part of the field typically
has the automatic gain control, phase-locked loop, and the timing
mark fields. The transfer of read channel settings, performance
data, and commands could occur during the first part of the field
when NRZ bus 535 is available. When that data has been transferred,
the command port 525 would send a command to the mux/sequencer 551
and the configuration registers 521 to enable the transfer of servo
position data from separator and memory 550 to the combiner and
memory 555 during the second part of the servo data 512. The
course-resolution data and the high-resolution data would then be
transferred and the current values would be updated for every servo
field in the same manner.
[0049] The mux/sequencer 551 selects the clock signal 534. When the
user data 511 is transferred over the NRZ data bus 535, the clock
signal 534 is synchronized to the NRZ data bus 535. When the other
data is transferred over the NRZ data bus 535, the clock signal 534
originates in the separator and memory 550. The clock signal is
synchronized to the servo data 512 on the NRZ bus 535 or is
synchronized to the data between the command port 525 and the
configuration registers 521 during the data transfer for the first
part of the servo data 512. The clock signal 534 is used to gate
the servo data 512 into the combiner and memory 555 or between the
command port 525 and configuration registers 521.
[0050] Those skilled in the art appreciate that some conventional
elements of the disk drive system 501 have been omitted for reasons
of clarity. Those skilled in the art can appreciate variations of
the above-described embodiments that fall within the scope of the
invention. For example various types of other data could be
transferred with the user data over the data bus instead of the
specific set of other data listed for FIG. 5. As a result, the
invention is not limited to the specific embodiments discussed
above, but only by the following claims and their equivalents.
* * * * *