Set Features command | Seagate ST480HM001, ST120HM001, ST120HM000

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 regis ter, clears BSY and generates an interrupt. 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
	02H	DMA Setup FIS Auto-Activate optimization
	03H	Device-initiated interface power state transitions
	06H	Software Settings Preservation
55H	Disable read look-ahead (read cache) feature
66H	Disable reverting to power-on defaults
82H	Disable write cache
90H	Disable use of SATA features
	02H	DMA Setup FIS Auto-Activate optimization
	03H	Device-initiated interface power state transitions
	06H	Software Settings Preservation
AAH	Enable read look-ahead (read cache) feature (default).
CCH	Enable reverting to power-on defaults

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

SEAGATE 600 SSD PRODUCT MANUAL, REV. B