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Browse Prior Art Database

Auto Analog to Digital Conversion in HDD system

IP.com Disclosure Number: IPCOM000013327D
Original Publication Date: 2001-May-30
Included in the Prior Art Database: 2003-Jun-18
Document File: 2 page(s) / 79K

Publishing Venue

IBM

Abstract

Disclosed is a system which enable quicker servo control of HDD without firmware transactions. By this system, HDC (Hard Disk Controller) can ADC (Analog Digital Convert) analog data related to servo control at each servo interrupt when servo information is read from disks and feed back or forward the digital data to servo

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Auto Analog to Digital Conversion in HDD system

Disclosed is a system which enable quicker servo control of HDD without firmware

transactions. By this system, HDC (Hard Disk Controller) can ADC (Analog Digital

Convert) analog data related to servo control at each servo interrupt when servo

information is read from disks and feed back or forward the digital data to servo

control algorithm.

In current design, ADC function is included in Spindle/VCM (Voce Coil Motor) driver and the converted digital data is transferred from the driver to HDC via serial interface. Not only both ADC and serial data transfer are controlled by firmware, but also the acquired data are handled by firmware. Future HDD has so many servo interrupts that firmware is occupied by the servo control and that other firmware transactions are delayed. This causes worse performance of the HDD. In the system disclosed here, ADC, serial data transfer and the data feed back/forward are synchronized with each servo interrupt as shown in Figure. When HDC recognizes servo interrupts, it generates the signal for driver to start ADC. Three of analog data are ADCed consecutively at each servo interrupt. At the same time, HDC acquires the three of the digital data via serial interface which were converted at the previous servo interrupt. The first data is VCM coil current and that is fed back to servo estimating function of HDC. This helps more precise estimation and realizes better recovery in case of misread...