Table 4.4 Signal delay times definition (3/3)
No. | Item | Time | Definition |
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|
|
|
14 | Reset to | 250 ms | The recommended maximum time after a hard RESET |
| selection | (recom- | condition until an SCSI target is able to respond with |
| time | mended) | appropriate status and sense data to the TEST UNIT |
|
|
| READY, INQUIRY, and REQUEST SENSE commands |
|
|
|
|
15 | Reset hold | 25 ∝s | The minimum time over which RST must be kept asserted |
| time |
|
|
|
|
|
|
16 | Selection | 200 ∝s | The maximum time required from the moment when |
| abort time |
| selection or deselection of an initiator or target is detected |
|
|
| until BSY is asserted |
|
|
|
|
17 | Selection | 250 ms | The minimum time required for an initiator or target in |
| timeout | (recom- | the selection or deselection phase to wait for a BSY |
| delay | mended) | response before it starts the timeout procedure |
|
|
|
|
18 | Transfer |
| The minimum allowable period, during sync data |
| period |
| transfer, between the start of consecutive REQ pulses and |
|
|
| the start of consecutive ACK pulses |
|
|
|
|
4.3.1BUS FREE phase
The BUS FREE phase is used to indicate that no SCSI device is actively using the SCSI bus, and that it is available.
SCSI devices shall detect the BUS FREE phase after the SEL and BSY signals are both false for at least a bus settle delay.
SCSI devices shall release all SCSI bus signals within a bus clear delay after the BSY and SEL signals become continuously false for a bus settle delay.
bus settle delay |
| bus clear delay |
|
|
|
BSY
SEL
others
BUS FREE phase
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