Set Features
6. ATA Command Specification
SONY AIT-1 Turbo drive SDX-460V series Ver.1.0
6-25
Subcommand Code
Table 6-4: SET FEATURES Register Definitions
Feature Value
Set Feature Command
03h
Set transfer mode based on value in Sector Count register.
66h
Disable reverting to power on defaults
CCh
Enable reverting to power on defaults
Set transfer mode
A host selects the transfer mechanism by Set Transfer Mode, subcommand code 03h, 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. One PIO mode and one DMA mode shall be selected at all times. Therefore, if
a Multiword DMA mode is selected then no UDMA mode is selected and if a UDMA mode is selected, no
Multiword DMA mode is selected. The host may change the selected modes by the SET FEATURES
command.
Table 6-5: SET FEATURES Transfer Mode
Sector Count
Transfer Mode
Transfer Speed
00h
PIO default mode
01h
PIO default mode, disable IORDY
08h
PIO transfer mode 0
3.333 MByte/s
09h
PIO transfer mode 1
5.221 Mbyte/s
0Ah
PIO transfer mode 2
8.333 MByte/s
0Bh
PIO transfer mode 3
11.111 MByte/s
0Ch
PIO transfer mode 4
16.667 MByte/s
20h
Multiword DMA mode 0
4.167 MByte/s
21h
Multiword DMA mode 1
13.333 MByte/s
22h
Multiword DMA mode 2
16.667 MByte/s
40h
Ultra DMA mode 0
16.667 MByte/s
41h
Ultra DMA mode 1
25.000 MByte/s
42h
Ultra DMA mode 2
33.333 MByte/s
43h
Ultra DMA mode 3
44.444 MByte/s
44h
Ultra DMA mode 4
66.667 MByte/s
45h
Ultra DMA mode 5
100.000 MByte/s
Note:
Issuing the set features transfer mode command only selects the speed for the particular type of
transfer. It does not select the transfer operation. The use of DMA for packet commands is selected
with the Packet command. See Packet Command (A0h) section 6.1.
Enable/disable reverting to defaults
Subcommand codes CCh and 66h are implemented for compliance with the ATAPI-6 standard. These
commands do not affect the operation of the SDX-460V, and should never return error.
If the SDX-460V ATAPI Tape Drive receives a SET FEATURES command with a Set Transfer Mode parameter
and a Sector Count register value of “00000000b”, it sets its default PIO mode. If the value is “00000001b”, the
Sony ATAPI Drive sets its default PIO mode and disable IORDY. The SDX-460V supports all PIO modes below
the highest mode supported.