Host Interface
4-42
C156-E224-01EN
4.4 SCSI Messages
SCSI messages are used to control the SCSI bus operating sequence. This section
explains how SCSI messages work.
4.4.1 Message formats
There are three types of message formats. In any format, the first byte of each
message is a message code (see Table 4.73).
•
1-byte message:
Only the message code
•
2-byte message:
Message with a message code from 20h to 2Fh. Each 2-
byte message consists of a 1-byte message code and a 1-
byte parameter. (The ODD does not support this type of
messages).
•
Extended message:
Multiple-byte message with message code 01h. An
extended message code and message length are defined
in each message.
4.4.2 Message types
Table 4.73 lists the types of messages provided by the ODD.
Table 4.73 Types of messages provided by ODD
Message
code (hex)
Message
Byte
count
Transfer direction
ATN
release
00
Command Complete
1
TARG
→
INIT
01
Extended Message
(Synchronous Data Transfer
Request)
n+2
(5)
TARG
←→
INIT
INIT
02
Save Data Pointer
1
TARG
→
INIT
04
Disconnect
1
TARG
→
INIT
05
Initiator Detected Error
1
TARG
←
INIT
INIT
06
Abort
1
TARG
←
INIT
INIT
07
Message Reject
1
TARG
←
INIT
INIT
08
No Operation
1
TARG
←
INIT
INIT
09
Message Parity Error
1
TARG
←
INIT
INIT
0C
Bus Device Reset
1
TARG
←
INIT
INIT
80
↓
FF
Identify
1
TARG
←→
INIT
Summary of Contents for MCJ3230SS
Page 1: ...C156 E224 01EN MCJ3230SS OPTICAL DISK DRIVE PRODUCT MANUAL ...
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Page 19: ...C156 E224 01EN xv Figure 6 1 Revision label 6 4 Figure 6 2 Revision number indication 6 4 ...
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Page 46: ...Specifications 2 12 C156 E224 01EN Figure 2 3 Example of alternate processing ...
Page 52: ...Installation Requirements 3 6 C156 E224 01EN Unit mm Figure 3 3 Dimensions without panel ...
Page 59: ...3 4 Cable Connections C156 E224 01EN 3 13 PC board Figure 3 11 Shape of setting terminal ...
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Page 124: ...Host Interface 4 50 C156 E224 01EN Figure 4 5 ARBITRATION phase ...
Page 125: ...4 5 Timing Rule C156 E224 01EN 4 51 µ Figure 4 6 SELECTION phase Figure 4 7 RESELECTION phase ...
Page 126: ...Host Interface 4 52 C156 E224 01EN Figure 4 8 Transfer in asynchronous mode ...
Page 127: ...4 5 Timing Rule C156 E224 01EN 4 53 Figure 4 9 Transfer in FAST SCSI mode ...
Page 128: ...Host Interface 4 54 C156 E224 01EN Figure 4 10 ATTENTION condition ...
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