Avago Technologies LSI21040 - Manual (Page 18)

3.75 pc 10.25 pc 11.25 pc 38.25 pc
4.333 pc
48.583 pc
52.5 pc
34.5 pc
44.25 pc
1-8 Using the LSI21040
enhanced check sends a known data pattern using the Read and Write
Buffer commands to detect additional problems. The margined check
verifies that the physical parameters have some degree of margin.
By varying LVD drive strength and REQ/ACK timing characteristics,
level 3 verifies that no errors occur on the transfers. These altered
signals are only used during the diagnostic check and not during normal
system operation. Should errors occur with any of these checks, the
system can drop back to a lower transmission speed, on a per-target
basis, to ensure robust system operation.