C141-E123-01EN1-281.5 Timing Rule1.5.1 Timing valueTable 1.15, 16, 17 give the timing required for operations on the SCSI bus.Table 1.15 SCSI bus control timing valuesTiming description Type Timing values1 Arbitration Delay min. 2.4μs2 Bus Clear Delay max. 800 ns3 Bus Free Delay min. 800 ns4 Bus Set Delay max. 1.6μs5 Bus Settle Delay min. 400 ns6 Cable Skew (1) max. 4 ns7 Data Release Delay max. 400 ns8 DIFFSENS voltage filter time min. 100 ms9 Physical Disconnection Delay min. 200μs10 Power on to Selection (2) max. 10 s11 Reset Delay min. 200 ns12 Reset Hold Time min. 25μs13 Reset to Selection (2) max. 250 ms14 Selection Abort Time max. 200μs15 Selection Time-Out Delay min. 250 ms16 System Deslew Delay min. 45 nsNote: (1) Cable Skew is measured at each device connection with the transmitted skew subtracted from thereceived skew. (2) This is a recommended time. It is not mandatory.Table 1.16 SCSI bus data & information phase ST timing valuesTiming values [ns] (5)Timing description Type Async Fast-5 Fast-10 Fast-20 Fast-401 ATN Transmit Setup Time min. 90 33 33 21.5 19.252 ATN Receive Setup Time min. 45 17 17 8.5 6.753 Cable Skew (3) max. 4 4 4 3 2.54 Receive Assertion Period (4) min. N/A 70 22 11 6.55 Receive Hold Time (4) min. N/A 25 25 11.5 4.756 Receive Negation Period (4) min. N/A 70 22 11 6.57 Receive Setup Time (4) min. N/A 15 15 6.5 4.758 Receive REQ (ACK) Period Tolerance min. N/A 1.1 1.1 1.1 1.19 Signal Timing Skew max. 8 8 8 5 4.510 REQ (ACK) Period min. N/A 200 100 50 2511 Transmit Assertion Period (4) min. N/A 80 30 15 812 Transmit Hold Time (4) min. N/A 53 33 16.5 9.2513 Transmit Negation Period (4) min. N/A 80 30 15 814 Transmit Setup Time (4) min. N/A 23 23 11.5 9.2515 Transmit REQ (ACK) Period Tolerance max. N/A 1 1 1 1Note: (3) Cable Skew is measured at each device connection with the transmitted skew subtracted from thereceived skew. (4) See Fig.1-17,18,19 for measurement points for the timing specifications. (5)SCSI bus timing values specified by the maximum transfer rate for the given range shall applyeven if a slower transfer rate within the given range is negotiated.
