4.4.10SEND command
The following table shows the normal sequence of the SEND command when used with this scanner.
Step | Bus phase | Initiator operation | ¨ Æ | Target operation |
|
|
|
|
|
1 | BUS FREE | Verifies bus free |
|
|
|
|
|
|
|
2 | ARBITRATION | Obtains bus>usage |
|
|
|
| right |
|
|
|
|
|
|
|
3 | SELECTION | Selects target | Æ |
|
|
|
|
|
|
|
|
|
| Drives BSY signal |
|
|
|
|
|
4 | MESSAGE OUT | Selects logical unit | Æ |
|
|
|
|
|
|
5 | COMMAND | Specifies SEND | Æ |
|
|
| (CDB) |
|
|
|
|
|
|
|
6 | DATA OUT |
| Æ | Transfer data |
|
|
|
|
|
7 | STATUS |
| ¨ | Reports GOOD status |
|
|
|
|
|
8 | MESSAGE IN |
| ¨ | Reports Command Complete |
|
|
|
|
|
|
|
|
| Releases BSY signal |
|
|
|
|
|
9 | BUS FREE |
|
|
|
|
|
|
|
|
(1)SEND command: COMMAND phase (initiator Æ target)
The SEND command is used by an initiator to send data to a target. The CDB of this command is shown in the following illustration.
| 7 | 6 | 5 | 4 |
| 3 |
| 2 | 1 | 0 |
| ||
|
|
|
|
|
|
|
|
|
|
|
|
| |
Byte 0 |
|
|
|
| Operation code X©2A |
|
|
|
| ||||
1 |
|
|
|
|
|
|
|
|
|
|
|
| |
| Logical unit number |
|
|
| (Reserved) |
| RelAdr | ||||||
2 |
|
|
|
|
| Transfer data type |
|
|
|
| |||
|
|
|
|
|
|
|
|
| |||||
|
|
|
|
|
|
|
|
|
|
| |||
3 |
|
|
|
|
| (Reserved) |
|
|
|
| |||
|
|
|
|
|
|
|
|
| |||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
4 | (MSB) |
|
| Transfer identification |
|
|
|
| |||||
|
|
|
|
|
|
|
|
| |||||
5 |
|
|
|
|
|
| (LSB) | ||||||
|
|
|
|
|
|
|
|
|
|
| |||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
6 | (MSB) |
|
|
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
| |||
7 |
|
|
|
|
| Transfer length |
|
|
|
| |||
|
|
|
|
|
|
|
|
| |||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
8 |
|
|
|
|
|
|
|
|
|
|
| (LSB) | |
|
|
|
|
|
|
|
|
|
|
|
|
| |
9 |
|
|
|
|
| Control |
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
|
|
| |||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
4 $ 68