Set Features (Efh); Table 6-8 Set Feature Register Definitions; Table 6-9 Transfer Mode Values - Samsung SPINPOINT V40 Series Product Manual

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.
Code
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.
PIO default mode
PIO default mode, disable IORDY
PIO flow control transfer mode
Multiword DMA mode
Ultra DMA mode
mode = transfer mode number
SpinPoint V40 Product Manual

Table 6-8 Set Feature Register Definitions

Table 6-9 Transfer mode values

MODE
DISK DRIVE OPERATION
Description
Bits(7:3)
00000
00000
00001
00100
01000
Bits(2:0)
000
001
mode
mode
mode
67