Filter
Top Products
DISK DRIVE OPERATION
SpinPoint V40 Product Manual
67
6.4.19 Set Features (EFh)
This command is used by the host to establish the following parameters, which affect the execution of certain
drive features as shown in Table 6-8.
Table 6-8 Set Feature Register Definitions
Code Description
02h Enable Write Cache
03h Set transfer mode based on value in Sector Count register
33h Disable Retry
42h Enable Automatic Acoustic management feature set.
44h Entire bytes of ECC apply on Read Long/Write Long commands
55h Disable read look-ahead feature
66h Disable reverting to power on defaults
77h Disable ECC
82h Disable Write Cache
88h Enable ECC
99h Enable Retries
AAh Enable read look-ahead feature
BBh 4 bytes of ECC apply on Read Long/Write Long commands
C2h Disable Automatic Acoustic management feature set.
CCh Enable reverting to power on defaults
When the drive receives this command, it sets BSY, checks the contents of the Feature register, clears BSY,
and generates an interrupt. If the value in the Feature register is not supported or is invalid, the drive posts an
Aborted Command error. Refer to section 6.6.3 for the protocol.
A host can choose the transfer mechanism by Set Transfer Mode and specifying a value in the Sector Count
register. The upper 5 bits define the type of transfer, and the low order 3 bits encode the mode value. Refer to
Table 6-9.
Table 6-9 Transfer mode values
MODE Bits(7:3) Bits(2:0)
PIO default mode 00000 000
PIO default mode, disable IORDY 00000 001
PIO flow control transfer mode 00001 mode
Multiword DMA mode 00100 mode
Ultra DMA mode 01000 mode
mode = transfer mode number