Fast-20 Timing Definition

Gene at Gene at
Fri Jan 6 06:52:30 PST 1995

I am not sure that Tak Asami's conclusions are correct that the examples he 
showed are allowed by any implementations of SCSI. But his conclusion is 
correct with layered standards if Fast 20 were combined with some non SCSI-3 
layered standards. (Mix and Match.) In any case I have no objection to his 
intent. But,

Tak Asami wrote: 
Table 1: SCSI bus timing values
| Timing description                       | fast-20  fast  slow  asynch   |
| Transfer Period during                   |                               |
| Synchronous Data Transfer Phases (note 5)| 50nsec  100nsec  200nsec  n/a |
Notes - 

5) The transfer period is measured from an assertion edge of REQ (ACK) 
   signal to the next assertion edge of the signal."

 The proposal needs to be changed to indicate that these are minimum values and 
larger values are allowed.


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