Specifications

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_REQDT_REQQAS_REQHOLD_MCSWR_FLOWRD_STRMRTI
PCOMP_EN
RTI
7
Transfer Width Exponent
6
REQ/ACK Offset5
Reserved = 00h4
Transfer period factor3
Parallel Protocol Request = 04h2
Extended message length = 06h1
Extended message = 01h0
01234567
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-8012.5Mt = 09h9<=Mi<= 9
Fast-1606.25Mt = 08h0<=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