Topic |
| Information |
SCSI Bus |
| The ANSI specification dictates the following: |
Requirements |
|
|
|
| The maximum signal path length between terminators is 3 |
|
| meters when using up to 4 maximum capacitance (25 pF) |
|
| devices and 1.5 meters when using more than 4 devices. |
|
| SCSI devices should be uniformly spaced between |
|
| terminators, with the end devices located as close as |
|
| possible to the terminators. |
|
| The characteristic impedance of the cable should be 90 +/- |
|
| 6 ohms for the /REQ and /ACK signals and 90 +/- 10 ohms |
|
| for all other signals. |
|
| The stub length(the distance from the controller’s external |
|
| connector to the mainline SCSI bus) shall not exceed.1m |
|
| (approximately 4 inches). |
|
| The spacing of devices on the mainline SCSI bus should be |
|
| at least three times the stub length. |
|
| All signal lines shall be terminated once at both ends of the |
|
| bus powered by the TERMPWR line. |
80ADAC Ultra2 S466 Hardware Guide