Samsung 3.5" hard disk drives User Manual

DISK DRIVE OPERATION 
 

SpinPoint V40 Product Manual 

52

 

This register contains the drive status. The contents of this register are updated at the completion of each 
command.  When BSY is cleared, the other bits in this register are valid within 400 nsec. If BSY=1, no other 
bits in this register are valid. If the host reads this register when an interrupt is pending, it is considered to be 
the interrupt acknowledge. Any pending interrupt is cleared whenever this register is read. 
 
NOTE: If Drive 1 is not detected as present, Drive 0 clears the Drive 1 Status register to 00h (indicating that 
the drive is Not Ready). 

7  6 5 4 3 2 1  0 

BSY DRDY 

DWF 

DSC DRQ 

CORR 

IDX  ERR 

 

•

  BSY (Busy) is set whenever the drive has access to the Command Block registers. The host should not 

access the Command Block registers when BSY=1. When BSY=1, a read of any Command Block 

register returns the contents of the Status register. This bit is set by the drive under the following 

circumstances: 

 

a)  Within 400 nsec after the negation of RESET- or after SRST has been set in the Device Control 

register. 

 
b)  Within 400 nsec of a host write of the Command register with a Read, Read Long, Read Buffer, 

Seek, Recalibrate, Initialize Drive Parameters, Read Verify, Identify Drive, or Execute Drive 
Diagnostic command. 

 
c) Within 

5 

µ

sec following transfer of 512 bytes of data during execution of a Write, Format Track, or 

Write Buffer command, or 512 bytes of data and the appropriate number of ECC bytes during the 
execution of a Write Long command. 

 

•

  DRDY (Drive Ready) indicates that the drive is capable of responding to a command. When there is an 

error, this bit does not change until the host reads the Status register. Then the bit again indicates the 

current readiness of the drive. This bit clears at power-on and remains clear until the drive is ready to 

accept a command. 

•

  DWF (Drive Write Fault) indicates the current write fault status. When an error occurs, this bit is not 

changed until the Status register is read by the host, at which time the bit again indicates the current write 

fault status. 

•

  DSC (Drive Seek Complete) indicates that the drive heads have settled over a track. When an error 

occurs, this bit is not changed until the Status register is read by the host, at which time the bit again 

indicates the current Seek Complete status. 

•

  DRQ (Data Request) indicates that the drive is ready to transfer a word or byte of data between the host 

and the drive. 

•

  CORR (Corrected Data) indicates that a correctable data error was encountered and the data has been 

corrected.  This condition does not terminate a data transfer. 

•

  IDX (Index) is set once per disk revolution. 

•

  ERR (Error) indicates that an error occurred during execution of the previous command. The bits in the 

Error register have additional information regarding the cause of the error.