Samsung 3.5" hard disk drives User Manual

DISK DRIVE OPERATION 
 

SpinPoint V40 Product Manual 

56

 

 
This command checks the power mode. 

 

If the drive is in, going to, or recovering from the Standby Mode, the drive sets BSY, sets the Sector Count 
register to 00h, clears BSY, and generates an interrupt. 
 
If the drive is in the Idle Mode, the drive sets BSY, sets the Sector Count register to FFh, clears BSY, and 
generates an interrupt. 
 

 
This command enables the host to alter the drive’s Micro-code.  The data transferred using this command is 
vendor specific. 
 

 
This command performs the internal diagnostic tests implemented by the drive. The DRV bit is ignored. Both 
drives, if present, shall execute this command. 
 
If Drive 1 is present:  
 

•

  Drive 1 asserts PDIAG- within 5 seconds. 

•

  Drive 0 waits up to 6 seconds for Drive 1 to assert PDIAG-. 

•

  If Drive 1 has not asserted PDIAG-, indicating a failure, Drive 0 appends 80h to its own diagnostic status. 

•

  Both drives execute diagnostics.  

•

  If a Drive 1 diagnostic failure is detected when Drive 0 status is read, then Drive 1 status is obtained by 

setting the DRV bit, and reading status. 

 
If there is no Drive 1 present: 

•

  Drive 0 posts only its own diagnostic results.  

•

  Drive 0 clears BSY, and generates an interrupt.  

 
The Diagnostic Code written to the Error register is a unique 8-bit code (shown in Table 6-5), not as the 
single bit flags defined in 6.3.4.4. 
 
If Drive 1 fails diagnostics, Drive 0 "ORs" 80h with its own status and loads that code into the Error register. 
If Drive 1 passes diagnostics or there is no Drive 1 connected, Drive 0 "ORs" 00h with its own status and 
loads that code into the Error register.