Seagate Understanding Set Features Command for Drives

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4.3.2Set Features command

This command controls the implementation of various features that the drive supports. When the drive receives this command, it sets BSY, checks the contents of the Features register, clears BSY and generates an inter- rupt. If the value in the register does not represent a feature that the drive supports, the command is aborted. Power-on default has the read look-ahead and write caching features enabled. The acceptable values for the Features register are defined as follows:

Table 9: Set Features command values

02H	Enable write cache (default).
03H	Set transfer mode (based on value in Sector Count register).
	Sector Count register values:
	00H	Set PIO mode to default (PIO mode 2).
	01H	Set PIO mode to default and disable IORDY (PIO mode 2).
	08H	PIO mode 0
	09H	PIO mode 1
	0AH	PIO mode 2
	0BH	PIO mode 3
	0CH	PIO mode 4 (default)
	20H	Multiword DMA mode 0
	21H	Multiword DMA mode 1
	22H	Multiword DMA mode 2
	40H	Ultra DMA mode 0
	41H	Ultra DMA mode 1
	42H	Ultra DMA mode 2
	43H	Ultra DMA mode 3
	44H	Ultra DMA mode 4
	45H	Ultra DMA mode 5
	46H	Ultra DMA mode 6
10H	Enable use of SATA features
55H	Disable read look-ahead (read cache) feature.
82H	Disable write cache
90H	Disable use of SATA features
AAH	Enable read look-ahead (read cache) feature (default).
F1H	Report full capacity available

Note. At power-on, or after a hardware or software reset, the default values of the features are as indi- cated above.

34	Barracuda 7200.9 Serial ATA Product Manual, Rev. C

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Contents Barracuda 7200.9 Serial ATA Page Contents Barracuda 7200.9 Serial ATA Product Manual, Rev. C List of Figures Page Introduction About the Serial ATA interface Drive specifications Specification summary tablesDrive specifications summary for 160 Gbyte models Drive specification ST3160811AS ST3160211ASBarracuda 7200.9 Serial ATA Product Manual, Rev. C Drive specifications summary for 120 Gbyte models Drive specification ST3120811AS ST3120211ASBarracuda 7200.9 Serial ATA Product Manual, Rev. C Drive specifications summary for 80 and 40 Gbyte models Drive specification ST380811AS ST380211AS ST340211ASBarracuda 7200.9 Serial ATA Product Manual, Rev. C Default logical geometry LBA modeFormatted capacity Cylinders Read/write heads Sectors per track 16,383Physical characteristics Recording and interface technologyStart/stop times Seek timeTypical seek times msec Read Write Power specifications Conducted noise Typical current profilesVoltage tolerance Power-management modes Active modeIdle mode Sleep modeEnvironmental specifications Acoustics VibrationOperating vibration Nonoperating vibrationElectromagnetic immunity ReliabilityRadio frequency environments Test Description Performance level Reference standardSafety certification Agency certificationElectromagnetic compatibility Korean RRLFCC verification Environmental protectionEuropean Union Restriction of Hazardous Substances RoHS Corrosive environment Barracuda 7200.9 Serial ATA Product Manual, Rev. C Configuring and mounting the drive Handling and static-discharge precautionsConfiguring the drive Serial ATA cables and connectorsMounting dimensions-top, side and end view Drive mountingBarracuda 7200.9 Serial ATA Product Manual, Rev. C Serial ATA Sata interface Hot-Plug compatibilitySerial ATA device plug connector pin definitions Serial ATA connector pin definitionsSignal Pin Function DefinitionSupported ATA commands Supported ATA commandsCommand name Command code in hex F4H Identify Device command Word Description ValueXx07H Description if bit is set to Bit Word Bit WordSet Features command Set Features command valuesM.A.R.T. commands 3 S.M.A.R.T. commandsCode in features register A.R.T. command Barracuda 7200.9 Serial ATA Product Manual, Rev. C Seagate Technology support services InternetPresales Support Technical SupportData Recovery Services Authorized Service Centers Warranty ServiceData Recovery Services Call Center Toll-free Direct dial Index RRL Sata Barracuda 7200.9 Serial ATA Product Manual, Rev. C Page Seagate Technology LLC