Command

Parameter write

 

~

b c

 

a

 

BSY

 

 

 

DRDY

 

 

 

 

 

DRQ

 

INTRQ

Data transfer

Expanded

Command

Min. 30 ∝ s (*1)

DRQ

INTRQ

Data Reg.

Selection

Data

IOR-

Word 0

IOCS16-

Status read

 

 

 

Status read

 

 

 

 

 

e

 

 

• • • •

e

 

 

 

d

f

 

d

• • • •

• • •

• • • •

• • • •

• • • •

1

2

255

*1 When the IDD receives a command that hits the cache data during read-ahead, and transfers data from the buffer without reading from the disk medium.

Figure 5.2 Read Sector(s) command protocol

Even if the error status exists, the drive makes a preparation (setting the DRQ bit) of data transfer. It is up to the host whether data is transferred. In other words, the host should receive the data of the sector (512 bytes of uninsured dummy data) or release the DRQ by resetting.

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Fujitsu MPG3XXXAH-E manual BSY Drdy DRQ Intrq, Ior, IOCS16