# US 5,710,675 A · Analog-to-digital converter for configuration control > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,710,675 A - Document ID: US5710675A - Status: Granted - Kind: A - Application number: 08/657,447 - Filed: 1996-05-29 - Granted: 1998-01-20 - Earliest claimed: 1996-05-29 - Assignees: Western Digital Corporation - Inventors: Marc B. Goldstone; Kenneth D. Donner; Ralph A. Proud, Jr. - Web page: https://patentgrep.com/patent/US5710675A ## CPC - G11B 19/20: Driving; Starting; Stopping; Control thereof - G11B 33/122: {Arrangements for providing electrical connections, e.g. connectors, cables, switches} - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) ## Abstract A disk drive circuit that includes a configuration resistor, a reference resistor, a capacitor and a processor. The processor is mounted on a first circuit assembly in the disk drive, such as the controller circuit board, and the configuration resistor is mounted on a second circuit assembly, such as the head-disk assembly (I-IDA). The resistance of the configuration resistor corresponds to the configuration of the second circuit assembly. The configuration may represent the number of heads or the type of preamplifier in the IDA. The processor calculates the resistance of the configuration resistor to determine the configuration of the second circuit assembly in the following manner. The processor charges the capacitor. The processor then allows the capacitor to discharge through a first circuit that includes both the configuration resistor and the reference resistor and measures the discharge time or time constant. The processor again charges the capacitor. The processor then allows the capacitor to discharge through a second circuit that includes the configuration resistor but not the reference and measures the time constant. The processor calculates the resistance of the configuration resistor in response to the ratio of the time constants of the first and second circuits. ## Claims ### Claim 1 In a disk drive having a first circuit assembly and a second circuit assembly, wherein the first circuit assembly includes a microprocessor and the second assembly has a configuration, a configuration apparatus for indicating the configuration of the second circuit assembly, comprising: a configuration resistor in the second circuit assembly having a resistance R.sub.s corresponding to one of a plurality of predetermined disk drive configurations; a connector electrically coupling said configuration resistor to the first circuit assembly; a reference resistor in the first circuit assembly having a predetermined resistance R.sub.r ; a capacitor in the first circuit assembly; microprocessor charging means for charging said capacitor; microprocessor discharging means for selectably discharging said capacitor through either a first R--C circuit coupled to the microprocessor having a resistance R.sub.t including both said configuration resistor and said reference resistor or a second R--C circuit coupled to the microprocessor having a resistance including said configuration resistor and not including said reference resistor; microprocessor measuring means for measuring a discharge time T.sub.t of said capacitor through said first R--C circuit and for measuring a discharge time T, of said capacitor through said second R--C circuit; microprocessor calculating means for calculating the resistance PR.sub.s of said configuration resistor in response to the discharge time T.sub.t and the discharge time T.sub.s ; and microprocessor configuration means for selecting the one of the plurality of predetermined disk drive configurations corresponding to the resistance R.sub.s. ### Claim 2 (depends on 1) The configuration apparatus recited in claim 1, wherein said microprocessor calculating means calculates the resistance R.sub.s in accordance with the equation T.sub.s R.sub.t =T.sub.t R.sub.s. ### Claim 3 (depends on 1) The configuration apparatus recited in claim 1, wherein said configuration resistor and said reference resistor are connected in parallel in said circuit having a resistance including both said configuration resistor and said reference resistor. ### Claim 4 (depends on 1) The configuration apparatus recited in claim 1, wherein each configuration represents a predetermined number of heads in the disk drive. ### Claim 5 (depends on 1) The configuration apparatus recited in claim 1, wherein each configuration represents one of a plurality of predetermined types of preamplifier circuits. ### Claim 6 (depends on 1) The configuration apparatus recited in claim 1, wherein: a first terminal of said reference resistor is connected to a first port of the microprocessor; a first terminal of said configuration resistor is connected to a first terminal of said capacitor, to a second terminal of said reference resistor and to a second port of the microprocessor; a second terminal of said configuration resistor is connected to electrical ground; and a second terminal of said capacitor is connected to electrical ground. ### Claim 7 (depends on 1) The configuration apparatus recited in claim 1, wherein: said microprocessor discharging means provides a signal at a first port of the microprocessor; said microprocessor charging means provides a signal at a second port of the microprocessor; and said microprocessor measuring means receives a signal at the second port of the microprocessor. ### Claim 8 A disk drive including a head-disk assembly (HDA) having at least one data storage disk and a controller assembly having a microprocessor, comprising: microprocessor read/write means in the controller assembly for controlling data transfers on the data storage disk; a configuration resistor in the HDA having a resistance R, corresponding to one of a plurality of predetermined HDA configurations; a first connector half on the controller assembly; a second connector half on the HDA connectable to said first connector half for electrically coupling said configuration resistor to the controller assembly; a reference resistor in the controller assembly having a predetermined resistance R.sub.r ; a capacitor in the controller assembly; microprocessor charging means for charging said capacitor; microprocessor discharging means for selectably discharging said capacitor through either a first R--C circuit coupled to the microprocessor having a resistance R.sub.t including both said configuration resistor and said reference resistor or a second R--C circuit coupled to the microprocessor having a resistance including said configuration resistor and not including said reference resistor; microprocessor measuring means for measuring a discharge time T.sub.t of said capacitor through said first R--C circuit and for measuring a discharge time T.sub.s of said capacitor through said second R--C circuit; microprocessor calculating means for calculating the resistance R.sub.s of said configuration resistor in response to the discharge time T.sub.t and the discharge time T.sub.s ; and microprocessor configuration means for selecting the one of the plurality of predetermined disk drive configurations corresponding to the resistance R.sub.s. ### Claim 9 (depends on 8) The disk drive recited in claim 8, wherein said microprocessor calculating means calculates the resistance R.sub.s in accordance with the equation T.sub.s R.sub.t =T.sub.t R.sub.s. ### Claim 10 (depends on 8) The disk drive recited in claim 8, wherein said configuration resistor and said reference resistor are connected in parallel in said circuit having a resistance including both said configuration resistor and said reference resistor. ### Claim 11 (depends on 8) The disk drive recited in claim 8, wherein the HDA includes a predetermined number of heads, and the configuration of the HDA represents number of heads in the HDA. ### Claim 12 (depends on 8) The disk drive recited in claim 8, wherein the HDA includes a preamplifier circuit having one a plurality of predetermined types, and the configuration of the HDA represents the type of preamplifier circuit in the HDA. ### Claim 13 (depends on 8) The disk drive recited in claim 8, wherein: a first terminal of said reference resistor is connected to a first port of the microprocessor; a first terminal of said configuration resistor is connected to a first terminal of said capacitor, to a second terminal of said reference resistor and to a second port of the microprocessor; a second terminal of said configuration resistor is connected to electrical ground; and a second terminal of said capacitor is connected to electrical ground. ### Claim 14 (depends on 8) The disk drive recited in claim 8, wherein: said microprocessor discharging means provides a signal at a first port of the microprocessor; said microprocessor charging means provides a signal at a second port of the microprocessor; and said microprocessor measuring means receives a signal at the second port of the microprocessor. ### Claim 15 A configuration apparatus in a disk drive, comprising: a first printed circuit board having a microprocessor mounted thereon; a second printed circuit board having one of a plurality of configurations; a first connector half connected to said first printed circuit board; a second connector half connected to said second printed circuit board and removably connected to said first connector half; a configuration resistor on said second printed circuit board having a resistance R.sub.s corresponding to the configuration of the second printed circuit board; a reference resistor on the first printed circuit board having a predetermined resistance R.sub.r ; a capacitor on the first printed circuit board; microprocessor charging means for charging said capacitor; microprocessor discharging means for selectably discharging said capacitor through either a first R--C circuit coupled to the microprocessor having a resistance R.sub.t including both said configuration resistor and said reference resistor or a second R--C circuit coupled to the microprocessor having a resistance including said configuration resistor and not including said reference resistor; microprocessor measuring means for measuring a discharge time T.sub.t of said capacitor through said first R--C circuit and for measuring a discharge time T.sub.s of said capacitor through said second R--C circuit; microprocessor calculating means for calculating the resistance R.sub.s of said configuration resistor in response to the discharge time T.sub.t and the discharge time T.sub.s ; and microprocessor configuration means for selecting the one of the plurality of predetermined configurations corresponding to the resistance R.sub.s. ### Claim 16 (depends on 15) The configuration apparatus recited in claim 15, wherein said microprocessor calculating means calculates the resistance R.sub.s in accordance with the equation T.sub.s R.sub.t =T.sub.t R.sub.s. ### Claim 17 (depends on 15) The configuration apparatus recited in claim 15, wherein said configuration resistor and said reference resistor are connected in parallel in said circuit having a resistance including both said configuration resistor and said reference resistor. ### Claim 18 (depends on 15) The configuration apparatus recited in claim 15, wherein: a first terminal of said reference resistor is connected to a first port of the microprocessor; a first terminal of said configuration resistor is connected to a first terminal of said capacitor, to a second terminal of said reference resistor and to a second port of the microprocessor; a second terminal of said configuration resistor is connected to electrical ground; and a second terminal of said capacitor is connected to electrical ground. ### Claim 19 (depends on 15) The configuration apparatus recited in claim 15, wherein: said microprocessor discharging means provides a signal at a first port of the microprocessor; said microprocessor charging means provides a signal at a second port of the microprocessor; and said microprocessor measuring means receives a signal at the second port of the microprocessor. ### Claim 20 In a disk drive having a first circuit assembly, a second circuit assembly and a connector for electrically coupling the first and second circuit assemblies, wherein the first circuit assembly includes a microprocessor, a reference resistor having a predetermined resistance R.sub.r, and a capacitor, and wherein the second circuit assembly has one of a plurality of predetermined disk drive configurations and includes a configuration resistor having a resistance R.sub.s corresponding to the configuration of the second circuit assembly, a method for detecting the configuration of the second circuit assembly, comprising the steps of: charging the capacitor a first time; discharging said capacitor through a circuit having a resistance R.sub.t including both the configuration resistor and the reference resistor; measuring a discharge time T.sub.t of the capacitor; charging the capacitor a second time; discharging the capacitor through a circuit having a resistance including the configuration resistor and not including the reference resistor; measuring a discharge time T.sub.s of the capacitor; calculating the resistance R.sub.s of the configuration resistor in response to the discharge time T.sub.t and the discharge time T.sub.s ; and selecting one of the plurality of predetermined disk drive configurations in response to the resistance R.sub.s. ### Claim 21 (depends on 20) The method recited in claim 20, wherein said selecting step includes a step of modifying a digital value in the first circuit assembly in response to the selected one of the plurality of predetermined disk drive configurations. ### Claim 22 (depends on 21) The method recited in claim 21, wherein the first circuit assembly modifies a signal coupled to a preamplifier in the second circuit assembly in response to the digital word. ### Claim 23 (depends on 21) The method recited in claim 21, wherein the first circuit assembly includes a controller circuit that translates a logical disk drive storage address into a physical disk drive storage address in response to the digital word.