DAP Technology 1394, Operation Manual

Page: 139 / 458

Symbol Recorder
139 Copyright © DapTechnology B.V., 2005-2019 - All Rights Reserved., 5/20/2019
Total Overview of StartRecordingS800toS400.sym
First Part: Toning
In the IEEE1394-2008 specification this state is named the "Disconnected" State (P0). Toning and speed
negotiation takes place here.
Speed negotiation
In the picture above we see the S400 capable node sending toning on the upper part of the screenshot
and the S800 capable node on the lower part.
Toning is used for speed negotiation. For detailed workings please refer to chapter 14.8.3 Beta-mode
speed negotiation of the IEEE1394-2008 specification.
The image above shows a total of 8 speed codes, 4 for each node. If we represent the presence of a tone
as a 1 and the absence as a 0, the top speed codes can be written as:
10000 - 10110 - 10110 - 11110
The bottom stream:
10000 - 10001 - 11110 - 11110
Decoded it means:
10000 : (Only Start of Toning)
10110 : Capable of S400
10001 : Capable of S800
11110 : Acknowledge, lets do S400
Second Part: Training
In the IEEE1394-2008 specification this state is named the "Untested" State (P11).
Startup effects
In the picture above we see the first few symbols of a new connection.
The errors are expected and caused by startup effects like clock synchronization between the two nodes
making the connection. FireStealth itself also needs to synchronize to the bit stream on the bus. In most
situations FireStealth will be able to lock on to the signal before the two nodes complete their training
period. This can also be seen in the picture.
In this example the software receives correct data after approximately 30 symbols. The bottom stream
was properly received after 17 symbols (in the example).
Training to Operation to Idle