Teledyne LeCroy SAS_SATA InFusion - Users Manual - Manual (Page 96)

Version 2.0 SAS InFusion User Manual
82
LeCroy Corporation
Creating Multi-Link Tests
As described, each SAS InFusion box has two BNC connectors on its rear panel that
allow it to connect to other SAS InFusion boxes in a daisy-chain. One connector is for
signal input, the other for signal output.
The BNC connectivity allows you develop wide-link test schemes. In such schemes, BNC
output on an upstream box is linked to the BNC input on its downstream neighbor.
The scenarios that runs on each box interacts with the scenarios that run on its neighbors
through trigger signals exchanged via the box BNC ports. The trigger signals are called
toggle events: BNC Input Toggle and BNC Output Toggle.
Each of the boxes in the daisy-chain monitors/modifies its own line only, but there is
synergy between the boxes by way of the BNC daisy-chain. In this fashion, you can use
a SAS InFusion daisy-chain to coordinate events and actions across multiple SAS or
SATA physical links.
In the example that follows, four boxes are connected in a daisy-chain. In this test, each
box runs the same scenario. The boxes are linked as follows:
Box 1 BNC Output connects to Box 2 BNC Input
Box 2 BNC Output connects to Box 3 BNC Input
Box 3 BNC Output connects to Box 4 BNC Input
Box 4 BNC Output connects to Box 1 BNC Input
Example 10:
Multi-Link
Test
In this example, the four separate links act as a wide link, and the same scenario runs in
each SAS InFusion box. This set-up allows detection of an Open Address Frame on any
of the four links, that is responded to on any of the other four links. The detected
OPEN_ACCEPT, regardless of which link it was detected on, is replaced with
OPEN_REJECT.
To achieve this result, the scenario has each box wating either for an Open Address
Frame or for a BNC signal from its neighboring box, meaning that it has detected an Open
Address Frame. In either case, the BNC output is toggled to signal the next box in the
BNC daisy-chain that the Open Address Frame has been detected, and that the box can
now transition to its next state (waiting for an OPEN_ACCEPT). This way, as soon as one
of the links gets an Open Address Frame, all four boxes will transition to state 1. State 1
waits for an OPEN_ACCEPT and replaces it with OPEN_REJECT, and this will happen
regardless of which link it is sent on, because ALL links are waiting for the same event.