HOST SOFTWARE INTERFACE
6 – 3
Command Register
Command Register
Command Register
Command Register
Command Register
Contains code for the command to be performed. Additional command information should be written to the
task file before the Command register is loaded. When this register is written, the BUSY bit in the Status
register sets, and interrupt request to the host clears; invalid commands abort. (Detailed information on interface
commands is given in Section 7.) Hex values for valid command formats follow:
Read Commands
Read Commands
Read Commands
Read Commands
Read Commands
Read Sector(s)
20h
Normal reads; retries enabled
21h
Normal reads; retries disabled
22h
Read Long; retries enabled
23h
Read Long; retries disabled
Read Verify Sector(s)
40h
Retries enabled
41h
Retries disabled
Read Sector Buffer
E4h
Read Multiple
C4h
Read DMA
C8h
C9h
No retries
Write Commands
Write Commands
Write Commands
Write Commands
Write Commands
Write Sector(s)
30h
Normal writes; retries enabled
31h
Normal writes; retries disabled
32h
Write Long; retries enabled
33h
Write Long; retries disabled
Write Verify Sector(s)
3Ch
Write Sector Buffer
E8h
Write Multiple
C5h
Write DMA
CAh
CBh
No retries
Mode Set/Check Commands
Mode Set/Check Commands
Mode Set/Check Commands
Mode Set/Check Commands
Mode Set/Check Commands
Set Features
EFh
Set Multiple Mode
C6h
Read Native Max Address
F8h
Set Max Mode
F9h
Power Mode Commands
Power Mode Commands
Power Mode Commands
Power Mode Commands
Power Mode Commands
Standby Immediate
94/E0h Stops drive spindle; do not change time-out value
Idle Immediate
95/E1h Starts spindle; do not change time-out value
Standby
96/E2h Stops spindle; change time-out value
Idle
97/E3h Starts spindle; change time-out value
Check Power Mode
98/E5h
Set Sleep Mode
99/E6h
Initialization Commands
Initialization Commands
Initialization Commands
Initialization Commands
Initialization Commands
Identify Drive
ECh
Initialize Drive Parameters
91h
Re-calibrate
1xh
Seek, Format, and Diagnostic Commands
Seek, Format, and Diagnostic Commands
Seek, Format, and Diagnostic Commands
Seek, Format, and Diagnostic Commands
Seek, Format, and Diagnostic Commands
Seek
7xh
Format Track
50h
Execute Drive Diagnostic
90h
S.M.A.R.T. Commands
S.M.A.R.T. Commands
S.M.A.R.T. Commands
S.M.A.R.T. Commands
S.M.A.R.T. Commands
Execute S.M.A.R.T.
B0h