10.1.4 PARALLEL PROTOCOL REQUEST (01,06,04H)
Parallel Protocol Request messages are used to negotiate a synchronous data transfer agreement and a
wide data transfer agreement and to set the protocol options between two SCSI devices.
IU_REQ
DT_REQ
QAS_REQ
HOLD_MCS
WR_FLOW
RD_STRM
RTI
PCOMP_EN
RTI
7
Transfer Width Exponent
6
REQ/ACK Offset
5
Reserved = 00h
4
Transfer period factor
3
Parallel Protocol Request = 04h
2
Extended message length = 06h
1
Extended message = 01h
0
0
1
2
3
4
5
6
7
Bit
Byte
Figure 186. Parallel Protocol Request.
PARALLEL PROTOCOL REQUEST messages are used to negotiate a synchronous data transfer
agreement and a wide data transfer agreement and to set the protocol options between the initiator
and the drive.
Transfer Period Factor selects the transfer period and determines the timing values for the transfer rate.
When both DT_REQ and IU_REQ are set to one, the following values are used. For the values larger than
9 is received from the initiator when both DT_REQ and IU_REQ are set to one, the drive responds with
these bits set to zero
.
Fast-80
12.5
Mt = 09h
9 <= Mi <=
9
Fast-160
6.25
Mt = 08h
0 <= Mi <=
8
Transfer Rate
Target Transfer
Period (ns)
Target
Response
Initiator Request
Figure 187. Initiator Request/Target Response (DT_REQ = 1, IU_REQ = 1)
Ultrastar 146Z10 hard disk drive specifications
183
Summary of Contents for IC35L018UCDY10
Page 2: ...This page intentionally left blank ...
Page 16: ...Ultrastar 146Z10 hard disk drive specifications xiv ...
Page 20: ...This page intentionally left blank ...
Page 21: ...Part 1 Functional specification Ultrastar 146Z10 hard disk drive specifications 5 ...
Page 22: ...This page intentionally left blank ...
Page 24: ...This page intentionally left blank ...
Page 34: ...This page intentionally left blank ...
Page 36: ...This page intentionally left blank ...
Page 63: ...Part 2 Interface specification Ultrastar 146Z10 hard disk drive specifications 47 ...