Momentus 5400.6 SATA Product Manual, Rev. A
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4.3.2 Set Features commandThis command controls the implementation of var ious features that the drive supports. When the drive receives this command, it sets BSY, checks the contents of the Features register, clears BSY and generates an inter-rupt. 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:
3Ultra DMA mode 3 is supported.
4Ultra DMA mode 4 is supported.
5Ultra DMA mode 5 is supported
6Ultra DMA mode 6 is supported
8Ultra DMA mode 0 is currently active.
9Ultra DMA mode 1 is currently active.
10 Ultra DMA mode 2 is currently active.
11 Ultra DMA mode 3 is currently active.
12 Ultra DMA mode 4 is currently active.
13 Ultra DMA mode 5 is currently active.
14 Ultra DMA mode 6 is currently active.
Bit Word 93
13 1 = 80-conductor cable detected, CBLID above VIH
0 = 40-conductor cable detected, CBLID below VIL
Table 8: Set Features command values
02HEnable write cache (default).
03HSet transfer mode (based on value in Sector Count register).
Sector Count register values:
00HSet PIO mode to default (PIO mode 2).
01HSet PIO mode to default and disable IORDY (PIO mode 2).
08HPIO mode 0
09HPIO mode 1
0AHPIO mode 2
0BHPIO mode 3
0CHPIO mode 4 (default)
20HMultiword DMA mode 0
21HMultiword DMA mode 1
22HMultiword DMA mode 2
40HUltra DMA mode 0
41HUltra DMA mode 1
42HUltra DMA mode 2
43HUltra DMA mode 3
44HUltra DMA mode 4