Seagate 30 Barracuda 7200.7 Product Manual, Rev. E

30 Barracuda 7200.7 Product Manual, Rev. E
4.1.3 Set Features command
This command controls the implementation of various feature s 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 cach ing featur es enab led. The acceptable values for the
Features register are defined as follows:
Note. At power-on, or after a hardware or software reset, the default values of the features ar e as indi-
cated above.
Bit Word 93
13 1 = 80-conductor cable detected, CBLID above VIH
0 = 40-conductor cable detected, CBLID below VIL
02HEnable write cache (default).
03H Set 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
45HUltra DMA mode 5
55HDisable read look-ahead (read cach e) feature.
82HDisable write cache.
AAHEnable read look-ahead (read cache) feature (default).
F1HReport full capacity available