Table 4.4 Signal delay times definition (2/3)
No. | Item | Time | Definition |
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4 | Bus free delay | 800 ns | The minimum time that an SCSI device shall wait from |
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| its detection of the BUS FREE phase (BSY and SEL both |
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| false for a bus settle delay) until its assertion of BSY |
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| when going to the ARBITRATION phase |
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5 | Bus set delay | 1.8 os | The maximum time for an SCSI device to assert BSY and |
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| its SCSI ID bit on the DATA BUS after it detects BUS |
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| FREE phase (BSY and SEL both false for a bus settle |
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| delay) for the purpose of entering the ARBITRATION |
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| phase |
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6 | Bus settle | 400 ns | The minimum time to wait for the bus to settle after |
| delay |
| changing certain control signals as called out in the |
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| protocol definitions |
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7 | Cable skew | 10 ns | The maximum difference in propagation time allowed |
| delay |
| between any two SCSI bus signals measured between |
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| any two SCSI devices |
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8 | Data release | 400 ns | The maximum time for an initiator to release the DATA |
| delay |
| BUS signals following the transition of the I/O signal |
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| from false to true |
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9 | Deskew delay | 45 ns | The minimum time required for deskew of certain |
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| signals |
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10 | Disconnection | 200 os | The minimum time that a target shall wait after |
| delay |
| releasing BSY before participating in an ARBITRATION |
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| phase when honoring a DISCONNECT message from the |
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| initiator |
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11 | Hold time | 45 ns | The minimum time added between the assertion of REQ |
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| (or REQB) or ACK (or ACKB) and the changing of the |
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| data lines to provide hold time in the initiator or target |
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| while using synchronous data transfers. REQB and |
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| ACKB timings only apply to optional wide data |
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| transfers. |
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12 | Negation | 90 ns | The minimum time that a target shall negate REQ (or |
| period |
| REQB) while using synchronous data transfers. Also, |
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| the minimum time that an initiator shall negate ACK (or |
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| ACKB) while using synchronous data transfers. REQB |
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| and ACKB timings only apply to optional wide data |
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| transfers. |
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13 | Power>on to | 10 sec | The recommended maximum time from power |
| selection time | (recom> | application until an SCSI target is able to respond with |
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| mended) | appropriate status and sense data to the TEST UNIT |
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| READY, INQUIRY, and REQUEST SENSE commands |
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