Table 2.12
PARALLEL PROTOCOL REQUEST message implied agreement
Responding SCSI device PARALLEL
PROTOCOL REQUEST response
Implied agreement
Non-zero REQ/ACK offset
Synchronous transfer (i.e., Each SCSI device transmits data
with a period equal to or greater than and a REQ/ACK offset
equal to or less than the negotiated values received in the
responding SCSI device's PPR message).
REQ/ACK offset equal to zero
Asynchronous transfer
Non-zero TRANSFER WIDTH
EXPONENT
Wide transfer (i.e., the initiator and the target transmit data
with a transfer width equal to the responding device's transfer
width). If the initiating SCSI device does not support the
responding SCSI device's TRANSFER WIDTH EXPONENT
then the initiating SCSI device shall MESSAGE REJECT the
PPR message.
TRANSFER WIDTH equal to zero
Eight-bit data
Protocol options equal to 0h and
transfer period factor equal to 9h
Eight-bit/asynchronous data transfer with PROTOCOL
OPTIONS field set to 0h
IU_REQ, DT_REQ, and QAS_REQ
Equal to zero
ST DATA IN and ST DATA OUT phases to transfer data
DT_REQ equal to one
DT DATA IN and DT DATA OUT phases transfer data with
IU RC
IU_REQ, and DT_REQ equal to one
DT DATA IN and DT DATA OUT phases with information
units
MESSAGE REJECT message
Eight-bit/asynchronous data transfer with PROTOCOL
OPTIONS field set to 0h
Parity error (on responding message)
Eight-bit/asynchronous data transfer with PROTOCOL
OPTIONS field set to 0h
Unexpected bus free
(as a result of the responding message)
Eight-bit/asynchronous data transfer with PROTOCOL
OPTIONS field set to 0h
No response
Eight-bit/asynchronous data transfer with PROTOCOL
OPTIONS field set to 0h
(1)
Target initiated PARALLEL PROTOCOL REQUEST negotiation
If the TARG recognizes that PARALLEL PROTOCOL REQUEST negotiation is required, it not
sends a PARALLEL PROTOCOL REQUEST message to the INIT.
(2)
Initiator initiated PARALLEL PROTOCOL REQUEST negotiation
If the INIT recognizes that PARALLEL PROTOCOL REQUEST negotiation is required, it
creates an attention condition and sends a PARALLEL PROTOCOL REQUEST message to begin
the negotiating process. After successfully completing the MESSAGE OUT phase, the TARG
shall respond with a PARALLEL PROTOCOL REQUEST message or a MESSAGE REJECT
message.
If an abnormal condition prevents the TARG from responding with a PARALLEL PROTOCOL
REQUEST message or with a MESSGE REJECT message then both SCSI devices shall use the
eight-bit/asynchronous data transfer mode with all the protocol options bits set zero to indicate ST
DATA IN and ST DATA OUT phases between the two SCSI devices.
C141-C015
185
Summary of Contents for MBA3300 NP SERIES
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Page 69: ...C141 C015 63 Figure 1 26 ARBITRATION phase ...
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Page 117: ...1 37 C141 C007 Figure 1 43 Bus phase sequence 1 of 2 ...
Page 118: ...38 C141 C015 Figure 1 43 Bus phase sequence 2 of 2 ...
Page 128: ...48 C141 C015 Figure 1 47 SPI information unit sequence during initial connection ...
Page 129: ...1 49 C141 C007 Figure 1 48 SPI information unit sequence during data type transfers ...
Page 130: ...50 C141 C015 Figure 1 49 SPI information unit sequence during data stream type transfers ...
Page 131: ...1 51 C141 C007 Figure 1 50 SPI information unit sequence during status transfers ...
Page 155: ...1 75 C141 C007 Figure 1 56 Connection to the LVD receivers ...
Page 161: ...Figure 2 1 Message format 154 C141 C015 ...
Page 166: ...Figure 2 2 SCSI pointer configuration C141 C015 159 ...
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