Hello all,

I have a question regarding a possible ambiguity in the SAS-2 spec at 6.7.4.2.3.

It says:

“If the phy’s receiver is trained and acquires dword synchronization before TLT, then the phy shall stop transmitting TRAIN patterns and start transmitting TRAIN_DONE patterns.”

It also says that upon transmitting 4 or more TRAIN_DONE patterns and receiving the minimum 1 TRAIN_DONE before MTT,

“then the phy shall:

a) stop transmitting TRAIN_DONE patterns;

b) start transmitting dwords from the link layer; and

c) consider the Train-SNW to be valid.”

When it says “stop transmitting” is the intention that TRAIN and TRAIN_DONE patterns always be sent in their entirety (primitive sequence followed by 58 scrambled dwords) before switching to the next item, or may the phy interrupt whatever TRAIN/TRAIN_DONE sequence it is in the middle of transmitting to switch to transmitting the next item?

Thanks,

-Geoff Hibbert

-Finisar Corporation