Seagate STT20000A, Product Manual

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ATAPI Interface Chapter 5
STT20000A Product Manual Page 35
Set Features (EFh)
If an unsupported feature is selected, the command is aborted. Otherwise, the
indicated parameter is set. The following list indicates the supported features:
Feature Number Set Feature Commands
03h Set Transfer Mode from Sector Count register
66h Disable reverting to power-on defaults (no-op)
CCh Enable reverting to power-on defaults (no-op)
Set Transfer Mode Feature
If the Set Transfer Mode feature (03h) is received, the Sector Count (ATAPI
Interrupt Reason) register is used to set the transfer mode based on the following
table. Any transfer modes not listed in the table cause the command to be aborted.
Sector Transfer Mode
00h PIO Transfer Mode 4 (default)
01h PIO Transfer Mode 2 (explicit IORDY disable)
08h PIO Transfer Mode 0
09h PIO Transfer Mode 1
0Ah PIO Transfer Mode 2
0Bh PIO Transfer Mode 3
0Ch PIO Transfer Mode4
10h Single Word DMA Mode 0
11h Single Word DMA Mode 1
12h Single Word DMA Mode 2
20h Multi-word DMA Mode 0
21h Multi-word DMA Mode 1
22h Multi-word DMA Mode 2