
Chapter 4 Command Operation
Page 4 - 6 |
| The Base Status Block |
The Base Status Block
Status Block
Format
The Status Block is another of the building blocks of the command structures you will be using when issuing commands. Used in conjunction with the Parameter Block, its purpose is to report the outcome of a command you issued.
The Status Block format is the same whether you have issued a
Single Command structures return only one Status Block. The Single Command structure will contain only the last Status
When you are using a Command List structure, multiple Status Blocks for any one command are possible depending on the retry and Sense Byte selections you have made (with the Unit Options or Extended Unit Options
The Status Block Format you will see used for all returned status information is illustrated in the following figure:
Address |
| Byte Memory Offset |
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Offset | Offset + 0 | Offset + 1 | Offset + 2 | Offset +3 |
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00H |
| Command Identifier |
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04H |
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| Error | Flags |
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08H |
| Status Information |
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0CH |
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Table 18: Base Status Block
Following is a brief description of each of the fields:
Command Identifier - This value will identify which Parameter Block has completed.
Flags
This byte can be polled to determine whether, and in what condition, a command completed. It has this format:
BITS
7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
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CC | ERR | RTY | DTT | DTG | CSB | 0 | TMS |
Table 19:
TMS Target Mode Status - This bit indicates that Status is being returned from the Target Mode Response command.
0 ⇒ The status was not a result of a Target Mode Response command.
1 ⇒ The status is the result of a Target Mode Response command.
21020285 D | User’s Guide |